Usmle review

Danil hammoudi.md

Sinoe medical association

Plasma cells are the end-effector cells of the B-lymphocyte lineage that produce and secrete antigen specific antibodies.

B-lymphocyte

Antibody

Plasma cells originate from antigen specific B cells after a number of activation, proliferation, and differentiation steps.

Malignant Plasma Cells
	However, when plasma cells become malignant due to a variety of causes multiple myeloma is the result. To the left is an immunohistochemistry stain of a bone marrow biopsy. The University of Arkansas for Medical Sciences was one of the first hospitals to use this particular method of staining for the CD-38 marker found on all plasma cells (in red).

· The normal plasma cell is a long-lived, mononuclear cell that does not divide.

· Plasma cells develop from an earlier precursor, the slowly proliferating plasmoblasts.

· These cells migrate to the bone marrow from lymph nodes after stimulation by antigen and helper T cells.

· Plasma cells produce most of the IgG and IgA in the serum, at a production rate of 1 ng per cell per day.

· After several weeks to months, apotosis (programmed cell death) of normal plasma cells occurs in the bone marrow.

· In contrast to normal plasma cells, myeloma cells have the appearance of immature plasmoblasts.

· Myeloma cells do not differentiate completely and are slow to proliferate.

· Their failure to differentiate is believed to be the result of chromosomal translocations, deregulation, or mutation of particular cancer genes.

· Although the exact etiology of MM is unknown, current evidence supports a "two-hit" hypothesis

· The two-hit hypothesis suggests that,

1. first, a cancer-stimulating event causes a subclinical monogammopathy;

2. then a second event leads to the development of MM.

· Exposure to these combined oncogenic events leads to the expression of the cancerous potential within the plasma cell.

· As a result, myeloma cells show continuous growth and prolonged survival.

· The survival of these myeloma cells is further enhanced by the presence of interleukin-6.

· Myeloma cells contain receptors for interleukin-6, and when interleukin-6 binds to this receptor, it promotes tumor growth and prolongs cellular survival.

· The combination of growth and prolonged survival lead to the clinical features of multiple myeloma

Plasma cell proliferation may occur in several anatomical sites as witnessed by the existence of multiple plasma cell-rich areas:

• lamina propria of the intestine
• medullary cords of lymph nodes
• white pulp and periarterioral sheaths of the spleen
• submucosa of the upper airways
• bone marrow

Malignant Plasma Cells

When plasma cells become malignant, the disease multiple myeloma is diagnosed, a neoplasm characterized by the accumulation of monoclonal plasma cells which show 3 features: IgG or IgA is the primary isotype of the secreted monoclonal immunoglobulins. Malignant plasma cells localize uniquely within the bone marrow. These cells are referred to as multiple myeloma cells. These cells also produce a number of cytokines, some identified as osteoclast activating factors, which in abundance cause the osteolytic lesions characteristic of multiple myeloma due to their abnormal resorption of bone, resulting in some cases in osteoporosis.

The normal cell counts are listed here demonstrating normal blood cell composition.

However, with multiple myeloma, all these blood cell counts become significantly reduced, leading to anemia, neutropenia, and thrombocytopenia.

multiple myeloma

1. Multiple myeloma is a malignant tumor of plasma cells that causes widespread osteolytic bone damage.
2. Multiple myeloma is the most common primary tumor of bone and is found in the spine, skull, ribs, sternum and pelvis but may affect any bone with hematopoietic red marrow
3. Multiple myeloma is a debilitating malignancy that is part of a spectrum of diseases ranging from monoclonal gammopathy of unknown significance (MGUS) to plasma cell leukemia
4. Multiple myeloma can cause a wide variety of problems.
5. The proliferation of plasma cells may interfere with the normal production of blood cells, resulting in leukopenia, anemia, and thrombocytopenia.
6. The cells may cause lytic lesions in the skeleton or in soft tissue masses[osteoclast activating factors] .
7. Feared complications of this malignancy are

1. bone pain,

2. hypercalcemia,

3. and spinal cord compression.

8. The aberrant antibodies that are produced lead to impaired humoral immunity, and patients have a high incidence of infection, especially with encapsulated organisms.
9. The overproduction of these antibodies may lead to

1. hyperviscosity,

2. amyloidosis,

3. and renal failure

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· most common primary malignant neoplasm of bone

· 50-70y; M:F 2:1

· symptoms: vague bone pain of progressive severity, fever, anemic sxs

· complications: pathologic fractures

· solitary plasmacytoma: solitary osseous focus of MM (uncommon)

x-ray findings:

· loss of bone density - from diffuse marrow involvement

· "punched out" lesions - esp. skull, long bones

· diffuse bone destruction - esp. pelvis, sacrum

· invasion of soft tissues - often paraspinal, extrapleural mass

· osteosclerosis - very rare

· metastatic calcifications - particularly kidneys, occ. lungs

NB: does not involve pedicles of spine

· The malignant cell of myeloma is believed to originate at a stage of B lymphocyte ontogeny in a cell more primitive than the end stage mature plasma cells which make up the bulk of the tumour.

· Unique immunoglobulin gene rearrangements can be demonstrated in the malignant plasma cells of most individuals and these rearrangements are stable throughout the course of the disease.

· Immunoglobulin gene rearrangement studies demonstrate that the process of somatic hypermutation has already occurred in the malignant clone, thus indicating that the cell of origin is at the stage of pre-plasma cell or memory B cell in lymphocyte differentiation.

· Such mutations in the immunoglobulin gene, by uniquely identifying the gene sequences of the idiotype, have allowed the development of sensitive assays for minimal residual disease based on the highly specific sequences of the complementary determining regions (CDRs) of the immunoglobulin gene as well as the development of in situ hybridisation staining of individual malignant cells to determine more accurately blood contamination and tissue distribution.

· Although previously thought to have been infrequent, recent studies have demonstrated the existence of chromosomal abnormalities in almost all patients with myeloma

· Abnormalities frequently involve the immunoglobulin heavy chain gene locus on the long arm of chromosome 14, often with translocations to a number of different non-immunoglobulin genes containing partner chromosomes.

· The site of translocation on chromosome 14 is different, however, from the sites of translocations seen in other B cell malignancies.

· In myeloma, the translocation involves the immunoglobulin switch regions which regulate heavy chain class switching to either the alpha, gamma, or epsilon chains.

· The non-immunoglobulin partners include chromosomes such as 11q, 4q, 6p and 16q, and newly identified oncogenes have been shown to be present at some of these breakpoints.

· Such genes include cyclin D, fibroblastic growth factor, and interferon regulatory factor IV.

· Interestingly, these cytogenetic changes are also present in patients with monoclonal gammopathy of uncertain significance (MGUS), suggesting that they are fundamental to the disease process but that additional events are required to develop fully the malignant phenotype.

· Another frequent and significant chromosome abnormality is the loss of chromosome 13, which has proven to be a significantly adverse prognostic indicator in patients with myeloma.

· Various other genetic abnormalities have been observed in patients with myeloma.

· These include ras mutations, retinoblastoma gene loss, p53 mutations and cyclin D inhibitor abnormalities.

· Such abnormalities are more often observed in patients with advanced disease and thus may be a reflection of increasing genetic instability as the malignancy progresses

· The Role of Human Herpes Virus 8 (HHV8) Infected Stroma in Myeloma

· Studies on the bone marrow stromal cells of myeloma patients have identified a key role for these cells which secrete cytokines crucial to the growth of the malignant clone, as well as an involvement in a variety of mechanisms which lead to the prevention of apoptosis in malignant plasma cells.

· For instance, Interleukin 6 (IL-6) produced by bone marrow stromal cells has been demonstrated both to enhance growth and prevent apoptosis of malignant plasma cells.

· HHV8 is a newly identified herpes virus which was first described in cases of HIV associated Kaposi's sarcoma.

· It has also been identified in two other B cell disorders, primary effusion lymphoma and multi-centric Castleman's disease.

· In these cases the virus is localised to the malignant cells.

· By contrast, some groups have recently documented HHV8 sequences in the genome of the stroma cells of patients with myeloma but not in the stromal cells of other lymphoid malignancies.

· HHV8 has been reported in both bone marrow biopsies and peripheral blood, and although different sequences have been determined among different patients, the same sequence has always been found in one particular patient at different sites.

· These and other workers on HHV8 have found, for instance, a viral homologue for the IL-6 gene, thus raising the possibility that virally infected stromal cells could potentiate the malignancy

· By contrast, European and other US-based studies have not always identified the virus, raising the question of whether this agent is truly aetiological or, perhaps, a reflection of HHV incidence in various population groups.

· Thus any possible role for this virus in the development of myeloma at this stage remains unclear and any potential studies to assess the possible utility of antiviral therapies have not yet been initiated.

· The presenting symptom of multiple myeloma is usually pain. The patient may have a normocytic, normochromic anemia secondary to marrow failure and an increased ESR.

· Hypercalcemia may cause confusion, weakness and lethargy. Other symptoms may include cachexia, spinal cord compression and renal insufficiency.

· Bacterial infections are common because of a lack of normal immunoglobulin production.

· Monoclonal immunoglobulin is found on serum electrophoresis. Light chain subunits of immunoglobulin are called BenceJones proteins and are present in urine.

· The radiological appearance of multiple myeloma is characterized by irregular lytic defects of different sizes. These lytic areas are often described as "punched out" and have no periosteal reaction.

· Erosion begins intramedullarly and progresses through the cortex.

· MRI is useful for delineating spinal lesions.

· Bone scan can fail to have increased uptake in 25% of patients suggesting a plain film skeletal survey should always be done.l

· On gross examination, the marrow space has been replaced by a diffuse gelatinous red brown tissue. Tumor nodules of approximately 1 cm in size may be present.

· Microscopically, multiple myeloma is composed of sheets of plasma cells. The degree of cytologic atypia of these cells has no prognostic value.

· The osteolytic lesions are caused by increased osteoclastic resorption that is stimulated by cytokines released by-the plasma cells.

· Treatment of multiple myeloma consists of palliative chemotherapy or bone marrow transplant.

· Only patients with complete remission of their disease experience any bony healing.

· Bisphosphonates are used to inhibit resorption of bone and subsequent hypercalcemia.

· Untreated, a patient with bony lesions will only survive an average of 6-12 months.

· The cause of death is usually infection or a hemorrhage.

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· A hallmark of the diagnosis of MM is the demonstration of monoclonal kappa or lambda light chain on serum or urine electrophoresis.

· An elevated IgG component is the most frequent abnormality found (53%), followed by elevated IgA (25%) and elevated IgD (1%).

· About 20% of those with MM also have an M-spike on electrophoresis due to the monoclonal light chains (Bence Jones protein).

^· Urine protein electrophoresis is the most efficient test to detect these monoclonal light chains (Bence Jones proteinuria).

· Less than 1% of MM patients present with no monoclonal proteins detected, thus resulting in what is termed the "nonsecretory" form of the disease.

· In these cases, immunofluorescent staining of plasma cells is necessary to identify the monoclonal light chains.

· Definitive diagnosis is made by bone marrow aspiration/biopsy confirming plasma cell proliferation.

· A plasma cell content of 15 to 20% is necessary for definitive diagnosis (normal is less than 5%).

· In addition to the nonsecretory form of MM, some patients have a monoclonal gammopathy of undetermined significance.

· These patients have elevated serum monoclonal IgG or IgA without evidence of MM.

· Monoclonal gammopathy is relatively common, occurring in about 0.15% of the general population.

· Long-term follow-up of these patients is critical given that overt MM can develop in 16% of these patients.

· Continued surveillance using radiography and protein electrophoresis is necessary.

Mortality/Morbidity:

• Multiple myeloma affects the kidneys in several ways. The most common means of renal injury are
1. direct tubular injury,
2. amyloidosis,
3. or involvement by plasmacytoma.
• Physicians manage the acute picture with plasmapheresis to rapidly lower circulating abnormal proteins.
• Conventional therapy may take weeks to months to show benefit.
• Renal impairment resulting from myeloma carries a very poor prognosis.

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• Spinal cord compression is one of the most severe adverse effects of myeloma.
• Reports indicate that as many as 20% of patients develop spinal cord compression at some point during the course of their disease.
• Symptoms typically are back pain, weakness in the legs or paralysis, numbness, or dysesthesias in the lower extremities.
• However, patients may present with upper extremity symptoms.
• The mechanism of these symptoms may be the development of an epidural mass with compression, a compression fracture of a vertebral body destroyed by myeloma, or, rarely, an extradural mass.
• The dysfunction may be reversible, depending on the duration of cord compression;
• however, only rarely is the dysfunction fully reversed.

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• A frequent complication of multiple myeloma is pathologic fractures.
• Bony involvement typically is lytic.
• Physicians should orthopedically stabilize (ie, typically pin) and irradiate these lesions.
• Careful attention to a patient's bony symptoms, intermittent radiographic surveys, and the use of bisphosphonates may be useful to prevent fractures.
• Patients with myeloma commonly develop hypercalcemia.
• The mechanisms include bony involvement and, possibly, humoral mechanisms.
• Treatment for myeloma-induced hypercalcemia is the same as for other malignancy-associated hypercalcemia;
• however, the dismal outcome observed with hypercalcemia in solid tumors is not observed in myeloma.

·
Risk Factors

	Age: Perhaps the most significant risk factor for multiple myeloma is age, the median age at diagnosis being 72 years.
Multiple myeloma is rare in people under 40, with a progressive increase in incidence with age. To the right is a logged graph that shows the dramatic increase in incidence from age 40 to >80.

In a study detecting MGUS with M-protein serum levels, the incidence increases 20-fold when comparing patients aged 30-49 and patients aged 70-89.

Race: Multiple myeloma is about twice as common for African Americans as white Americans in the United States. The incidence of disease is lowest in Japan, with only a 2.7% detection of monoclonal protein in the serum in persons over age 60 as compared to a 10% detection in the U.S.
	Genetics: The incidence of multiple myeloma is lowest among Japanese and Chinese people regardless of which country of residence, suggesting that the disease is determined more by genetic than environmental factors. Neither blacks nor whites showed a change in incidence when comparing different countries of residence.

A large study was done on white & black males to determine whether there was an association of human leukocyte antigens of class I and Class II with the disease:

• Black cases had higher frequencies for
1. Bw65,
2. Cw2,
3. DRw14.
• White cases had higher gene frequencies for
1. A3
2. Cw2.
• These findings suggest that the Cw2 allele confers susceptibility to the development of multiple myeloma, but doesn't explain the higher risk among blacks.

A study was done using 43 families to determine the genetic association among those with either MGUS or multiple myeloma:

• Of the 43 families, MM or MGUS was detected in 7 first-degree relatives (parent and child), 23 second-degree relatives (siblings), one third degree relative (aunt, niece), and 3 fourth degree relatives (first cousins).
• However, no clear Mendelian pattern of inheritance has been established for MM or MGUS.

Smoking: Studies have shown that the risk of developing myeloma is 3-fold greater in subjects who have ever smoked than in those who had never smoked.
	Occupation: Studies have also shown a positive association between the following specific occupations/industries and myeloma: agriculture (predominantly farming) metals rubber manufacturing occupations where workers are exposed to benzene or asbestos petroleum refining and petroleum production fuel combustion wood, leather, and textile production painting hair dye manufacturing

No Longer Considered Risk Factors:

Radiation Exposure:

Although studies done on Hiroshima/Nagasaki radiation exposure survivors between 1950 and 1976 showed a positive association with multiple myeloma, reanalysis of the data using updated methods (Dosimetry System) shows no such association with the disease nor frequency of a monoclonal gammopathy.

Socioeconomic Status:

A case-control study at Duke failed to demonstrate any association of myeloma with family income, education, occupation, dwelling size or an index of crowding in the home.

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Symptoms

The symptoms of multiple myeloma most commonly include one or more of the following:

· bone pain and skeletal fractures, including compression fractures of the spine, which can cause severe pain and neurologic symptoms

· infections, especially bacterial infections of the respiratory and urinary tracts

· generalized symptoms including fatigue, weight loss, and general malaise, which can relate to anemia

· hypercalcemia, which can cause nausea, vomiting, altered mental states, depression, headache, and in severe cases, coma

· loss of kidney function, which can cause fatigue, a buildup of fluid in the lower limbs, and excessive thirst

· hyperviscosity (a thickening of the blood caused by excessive protein) can cause bruising, rash, nosebleeds, vision loss, headache, dizziness, and peripheral neuropathy (numbness, tingling, burning pain in the extremities)

In about one third of patients, multiple myeloma is detected before symptoms appear, through routine blood tests that pick up elevated levels of immunoglobulin proteins

The symptoms of MM vary from person to person, and will depend on the extent and stage of the disease. The symptoms are caused by the malignant plasma cells and the myeloma paraproteins they produce.

Symptoms involve three major body systems; the skeletal system, the renal system and the bone marrow.

· The Skeletal System

The most common symptom associated with MM is bone pain.

Bone pain is experienced by approximately 70% of myeloma sufferers.

Pain is frequently felt in the

· lower back,

· ribs

· spine,

· and is caused by myeloma cells eroding the bones causing them to fracture easily.

On x-ray imaging, the areas of myeloma activity can be seen as "punched out" lesions on the bone surface

Bone erosion may lead to hyper-calcemia (high blood calcium levels). People suffering from hyper-calcemia may experience symptoms of confusion, nausea, tiredness, constipation, thirst, increased urine output, and dehydration.

· The Renal System

Kidney problems occur in approximately 50% of patients with MM at some stage of their illness.

Kidney function may be affected for a number of reasons.

Firstly, the myeloma proteins circulating in the blood can be deposited in the kidneys and cause obstruction and inflammation.

(Those abnormal proteins excreted in the urine is called Bence-Jones protein.)

Secondly, calcium from the eroded bones may be deposited in the kidneys causing obstruction and inflammation.

Kidney failure can result if these causes of kidney function are left untreated, especially if dehydration should develop.

Other aggravating factors may include urinary tract infection and high blood urate level that MM patients are also prone to develop.

· The Bone Marrow

Plasma cells are predominantly found within the bone marrow, which is the location of blood cell production. When the plasma cell becomes malignant it gradually takes over of the bone marrow, preventing it from producing normal blood cells. As such, myeloma sufferers may experience

· anemia,

· thrombocytopenia

· leukopenia.

Another complication of multiple myeloma is hyper-viscosity.

This condition occurs in approximately 5% of individuals with myeloma.

It refers to the presence of high concentrations of myeloma paraprotein in the blood.

These paraproteins increase the ‘viscosity’ or thickness of the blood, potentially impairing blood circulation.

The viscous blood flow may provoke a heart attack or stroke.

Similarly impeded circulation to small blood vessels in the eyes may cause visual disturbances or blindness.

Restricted blood circulation to the vessels of organs or limbs may lead to pain and tissue necrosis.

Presenting symptoms include

1. bone pain,

2. pathologic fractures,

3. weakness, anemia,

4. infection (often resulting from pneumococcal infection),

5. hypercalcemia,

6. spinal cord compression,

7. or renal failure.

Physicians increasingly are identifying asymptomatic patients through routine blood screening.

Typically, a large gap between the total protein and the albumin observed on an automated chemistry panel suggests a problem (ie, protein minus albumin equals globulin).

• Bone pain

• This is the most common presenting symptom. Most series report that 70% of patients have bone pain at presentation.

• The lumbar vertebrae are one of the most common sites of pain.

• Pathologic fractures and bone lesions

• Pathologic fractures are very common; 93% of patients have more than one site of bony involvement.

• A common presentation is a severe bony event.

• Spinal cord compression

• The symptoms that concern physicians are back pain, weakness (the most common cause of weakness in patients with myeloma is anemia, which may be quite severe), numbness, or dysesthesias in the extremities.

• Patients who are ambulatory at the start of therapy have the best neurologic outcome.

• This complication occurs in approximately 10-20% of patients at some time during the course of disease.

• Bleeding

• Occasionally, a patient may come to medical attention for bleeding resulting from thrombocytopenia.
• In some patients, monoclonal protein may absorb clotting factors and lead to bleeding, but this development is rare.

• Hypercalcemia

• Patients may have hypercalcemia if they present with confusion, somnolence, bone pain, constipation, nausea, and thirst.
• This complication may be present in as many as 30% of patients at presentation.

• Infection

• Abnormal humoral immunity and leukopenia may lead to infection.
• Pneumococcal organisms commonly are involved, but shingles (ie, herpes zoster) and Haemophilus infections also are more common among patients with myeloma.

• Hyperviscosity

• Epistaxis may be a presenting symptom of myeloma with a high tumor volume. Occasionally, patients may have such a high volume of monoclonal protein that their blood viscosity increases, resulting in complications such as stroke, myocardial ischemia, or infarction.
• Patients may report headaches and somnolence, and they may bruise easily and may have hazy vision. Patients typically experience these symptoms when their serum viscosity is greater than 4 times that of normal serum.

• Neurologic symptoms

• Carpal tunnel syndrome is a common complication of myeloma.
• Meningitis (especially resulting from pneumococcal or meningococcal infection) is more common in patients with myeloma.
• Some peripheral neuropathies have been attributed to myeloma.

Physical:

• Patients may have pallor resulting from anemia.

• Patients may have ecchymoses or purpura resulting from thrombocytopenia.

• Bony tenderness is common, resulting from focal lytic destructive bone lesions or pathologic fracture.

• Neurologic findings may include a sensory level change (ie, loss of sensation below a dermatome corresponding to a spinal cord compression), weakness, or carpal tunnel syndrome.

• Extramedullary plasmacytomas

• These plasmacytomas, which consist of soft tissue masses of plasma cells, are not uncommon.

• Plasmacytomas have been described in almost every site in the body.

• Although the aerodigestive tract is the most common location, reports also describe orbital, ear canal, cutaneous, gastric, rectal, prostatic, and retroperitoneal lesions.

• Amyloidosis

• Some patients with multiple myeloma develop amyloidosis.
• The characteristic physical examination findings that suggest amyloidosis include the following:
• The shoulder pad sign is defined by bilateral swelling of the shoulder joints secondary to amyloid deposition.
1. Physicians describe the swelling as hard and rubbery.
2. Amyloidosis may also be associated with carpal tunnel syndrome and subcutaneous nodules.
• Macroglossia is a common finding in patients with amyloidosis.
• Skin lesions described as wax-colored papules and nodules may occur in patients with amyloidosis and most commonly are observed on the face, lips, ears, and torso.
• Postprotoscopic peripalpebral purpura strongly suggests amyloidosis.
• Patients may develop raccoonlike dark circles around their eyes following any procedure that parallels a prolonged Valsalva maneuver.
• The capillary fragility associated with amyloidosis may account for this observation.

• The accepted schema for diagnosis is as follows:

• I = Plasmacytoma on tissue biopsy
• II = Bone marrow with greater than 30% plasma cells
• III = Monoclonal globulin spike on SPEP with an IgG peak of greater than 3.5 g/dL or an IgA peak of greater than 2.0 g/dL or UPEP (in the presence of amyloidosis) greater than 1 g/24 h

• a = Bone marrow with 10-30% plasma cells
• b = Monoclonal globulin spike present but less than category III
• c = Lytic bone lesions
• d = Residual normal IgM of less than 50 mg/dL, IgA of less than 100 mg/dL, or IgG of less than 600 mg/dL

• The following combinations of findings are used to make the diagnosis:

• I plus b
• I plus c
• I plus d
• II plus b
• II plus c

• II plus d

• III plus a

• III plus c

• III plus d

• a plus b plus c or a plus b plus d

Causes:

• Genetic causes

• The Mayo clinic found disease in 8 siblings out of 440 patients; these 8 siblings had different heavy chains but the same light chains.

• Ongoing research is investigating whether the human leukocyte antigen (HLA)-Cw5 or HLA-Cw2 may play a role in the genesis of myeloma. In small studies, researchers have identified both of these antigens in an increasing number of patients with myeloma.

• Environmental or occupational causes

• A British case-controlled study of 399 patients with myeloma reported a relative risk of 1.8 for patients exposed to the agriculture, food processing, and chemical industries.

• A second study (ie, 100 cases, 100 controls) in Baltimore showed an increased risk of 3.7 for patients exposed to petrochemicals, 3.5 for patients exposed to asbestos, and 3.5 for patients exposed to laxatives.

• Conflicting data exist regarding an association between hair dye and myeloma. The American Cancer Society prospective mortality study suggested that individuals who have used hair dye for a long time (ie, >20 y) have an increased risk of developing myeloma.

• MGUS: Approximately 19% of patients with MGUS develop multiple myeloma within 2-19 years.

• Radiation

• Radiation is linked to myeloma.

• In 109,000 survivors of the bombing of Nagasaki, 29 died from myeloma from 1950-1976; however, some recent studies do not confirm that these survivors have an increased risk of developing myeloma.

HOW IS MYELOMA DIAGNOSED ?

The initial approach to the patient is to establish the diagnosis by:

1. Detection of an M-protein in the serum or urine.

2. Detection of more than 10% plasma cells on a bone marrow examination.

3. Detection of lytic bone lesions or generalized osteoporosis in skeletal x-rays.

4. Presence of soft tissue plasmacytomas.

Other important tests which help to evaluate patients include:

· b2 microglobulin

· C-reactive protein

· blood count

· calcium level

· kidney function

· type of abnormal myeloma protein [bence jones protein type]

Bence Jones protein: a portion of the abnormal myeloma protein referred to as the "light chains

monoclonal (M) protein: the protein made by myeloma cells

· A critical diagnostic criteria, however, is the characteristic abnormal plasma cell pathology. It is no longer adequate to assume that the demonstration of lytic bone lesions plus a paraprotein is sufficient for the diagnosis. Morphological confirmation can usually be easily sought from bone marrow aspiration or from fine needle aspiration of a skeletal lesion or plasmacytoma. The main differential diagnoses are

· MGUS,

· smouldering myeloma,

· systemic amyloidosis,

· lymphoma

· metastatic carcinoma.

· Newer radiological investigations, such as magnetic resonance imaging (MRI) of the spine, have proven to be extremely useful, especially for the accurate demonstration of neurological complications.

· In the future, whole body MRI may become the radiological investigation of choice for all myeloma patients.

· An application of particular importance may be the accurate separation of solitary plasmacytoma from disseminated multiple myeloma.

· Several additional investigations are of importance in predicting the prognosis and guiding treatment decisions in individual patients.

· These include

1. the bone marrow plasma cell labelling index (PCLI)

2. and blood levels of beta-2-microglobulin ("ß2M),

3. C-reactive protein,

4. thymidine kinase

5. lactic acid dehydrogenase.

· Of these, the ß2M and PCLI are the most powerful predictive assays.

· The differentiation of smouldering myeloma from active (treatment-requiring) myeloma is not always easy.

· The decision to instigate specific therapy, as opposed to observation, is based on a number of criteria.

· Of the laboratory investigations, the PCLI is particularly useful.

· Using dual colour fluorescent techniques, this assay measures the percentage of plasma cells (bearing the light chain of the malignant clone) in S phase of the cell cycle (detected by propidium iodine or bromodeoxyuridine).

· Recent adaptation to the flow cytometer has dramatically reduced the labour-intensiveness of this test and thus widened its application.

· A strongly elevated labelling index suggests that the patient has active disease, while a low labelling index is a sine qua non of smouldering myeloma or MGUS.

· ß2M largely reflects renal function and is in itself an important prognostic indicator for myeloma.

· In combination with the PCLI, it provides the most accurate prognostic information, not only in patients who are treated with conventional chemotherapy, but also in patients who are submitted to high dose therapy and transplantation protocols.

· For instance, a patient under 60 years of age, who presents with a low ß2M and a low labelling index, has a median survival of over six years when treated with conventional chemotherapy alone.

· The application of information from prognostic marker studies is obviously of great relevance when considering the use of high dose therapy protocols and especially allogeneic transplantation.

Following this a number of tests will be ordered.

1. Blood tests are routinely ordered to determine blood cell counts. In approximately 80-90% of cases, the paraproteins produced by the malignant plasma cells can be detected and quantitated in the blood.
2. Many patients who have the myeloma protein in their blood also have fragments of myeloma protein in their urine.
3. To detect and measure the urinary protein fragments, patients are asked to do a 24 hour urine collection.
4. . Additional blood tests can ascertain the function of vital organs, blood calcium level, clotting factors, blood grouping, and virology screening such as hepatitis and HIV status.

5. X-rays of the bones (Skeletal survey) are frequently taken to determine the extent to which they are affected.
6. Typically, x-rays are taken of the chest, spine, pelvis, arms, legs and skull.
7. Occasionally, CT scans and/or MRI scans are also required.

Chest X-rays are likely to be taken if a chest infection is suspected.

Blood, phlegm, urine and stool cultures may also be collected to identify the site of infection, especially if fever is present. ECG (electrocardiograph) and GBPS (gated blood pool scan) may be required to assess your heart function.

The diagnosis of multiple myeloma requires examination of the bone marrow.

This procedure is called a bone marrow biopsy, and is performed under intravenous sedation and local anaesthesia. Examination of the bone marrow will show an excessive numbers of plasma cells with an associated reduction in the normal cells.

A bone marrow biopsy is an outpatient procedure performed under local anaesthesia and sedation. Using a special disposable needle and syringe, the doctor will withdraw a small amount of marrow blood from the hip bone (or uncommonly the breast bone), along with a tiny core of bone marrow tissue.

The procedure takes around twenty minutes to complete and involves minimal discomfort.

It is only after these tests are performed that an accurate diagnosis can be made.

The most appropriate therapy can then be recommended taking into account the findings of these test results, current symptoms, age and health history.

The following diseases can be associated with secretion of a monoclonal protein (M-Component) in the blood:

· monoclonal gammopathy of undetermined significance (MGUS)

· multiple myeloma

· Waldenstrom's macroglobulinemia

· malignant lymphoma or primary systemic amyloidosis

Stage Information

Isolated plasmacytoma of bone

• If a solitary lytic lesion of plasma cells is found on skeletal survey in an otherwise asymptomatic patient and a bone marrow examination from an uninvolved site contains less than 5% plasma cells, the patient has an isolated plasmacytoma of bone.
• About 25% of patients have a serum and/or urine M-protein;
• this should disappear following adequate irradiation of the lytic lesion.
• When clinically indicated, magnetic resonance imaging (MRI) may reveal unsuspected bony lesions which were undetected on standard radiographs.

Extramedullary plasmacytoma

• Patients with isolated plasma cell tumors of soft tissues, most commonly occurring in the tonsils, nasopharynx, or paranasal sinuses, should have skeletal x-rays and bone marrow biopsy.
• If these tests are negative, the patient has extramedullary plasmacytoma.
• About 25% of patients have serum and/or urine M-protein; this should disappear following adequate irradiation.

Macroglobulinemia

• Macroglobulinemia is a proliferation of plasmacytoid lymphocytes secreting an IgM M-protein.
• Patients often have lymphadenopathy and hepatosplenomegaly, but bony lesions are uncommon.
• There is no generally accepted staging system.

· The term macroglobulinemia describes an increase in the serum concentration of a monoclonal IgM.

· Most patients are asymptomatic and do not require treatment.

· The most common symptoms and signs, when they develop, are

§ fatigue,

§ manifestations of hyperviscosity (headache, epistaxis, visual disturbances),

§ and neurologic abnormalities.

§ Lymphadenopathy and splenomegaly are found in about one third of patients.

§ The increased intravascular concentration of high molecular weight IgM leads to an expansion of the plasma volume, a dilutional anemia, and in extreme cases, congestive heart failure.

§ Sludging of the blood can be seen in conjunctival and retinal veins with dilatation and segmentation of vessels ("link sausage" appearance), retinal hemorrhages, and papilledema.

§ Similar problems with the circulation of blood in the CNS can cause ataxia, nystagmus, vertigo, confusion, and disturbances of consciousness.

· The various disorders associated with the appearance of a monoclonal IgM include:

1. Monoclonal Gammopathy of Undetermined Significance (MGUS). Patients are asymptomatic, the M-protein is stable, and there is no lymphadenopathy, splenomegaly, or bony lesions.

2. Waldenstrom's Macroglobulinemia (WM). Patients are symptomatic, have lymphoplasmacytic marrow infiltration and a rising serum IgM concentration, and may have lymphadenopathy or splenomegaly. Rarely, patients with WM have lytic bone lesions. (Refer to the PDQ summary on Adult Non-Hodgkin's Lymphoma Treatment for more information.)

3. Absolute lymphocyte count exceeding 5,000 cells per cubic millimeter. The patient may be classified as having chronic lymphocytic leukemia (CLL) if the lymphocytes are of the small, well-differentiated variety. CLL must be differentiated from the lymphoplasmacytosis that may occur as a peripheral blood manifestation of WM.

4. Lymphoplasmacytic lymphoma. When a lymph node biopsy demonstrates the pathologic characteristic of a lymphoma, this becomes the diagnosis.

5. Chronic cold agglutinin disease. Patients have a high cold agglutinin titer and no morphologic evidence of neoplasia. These patients often have a hemolytic anemia that is aggravated by cold exposure. The IgM has kappa light chains in more than 90% of these patients.

Monoclonal gammopathy of undetermined significance

• Patients with MGUS have an M-protein in the serum without findings of multiple myeloma, macroglobulinemia, amyloidosis, or lymphoma and with fewer than 10% plasma cells in the bone marrow.
• These patients are asymptomatic and should not be treated.
• They must, however, be followed carefully since about 2% per year will progress to develop one of the symptomatic B-cell neoplasms and may then require therapy.

MGUS	Smoldering Multiple Myeloma	Overt Multiple Myeloma
Serum M-Protein (Usually <3 g/dl Few than 10% plasma cells, and no aggregates on biopsy No anemia, renal failure, or hypercalcemia Ancillary tests negative Bone lesions absent on radiographic bone survey Bone marrow contains <10% plasma cells without aggregates on biopsy Bone marrow plasma cell L1<1.0% Plasmablasts absent	Serum M-protein (usually >3 g/dl) 10% or more marrow plasma cells or aggregates on biopsy No anemia, renal failure, or hypercalemia attributable to myeloma Ancillary tests negative Bone lesions absent on radiographic bone survey Bone marrow contains <10% plasma cells without aggregates on biopsy Bone marrow plasma cell L1<1.0% Plasmablasts absent	M-protein present in serum or urine 10% or more marrow plasma cells or aggregates on biopsy Ancillary findings (one or more): must not be attributable to another cause Anemia Lytic lesions (osteoporosis satisfies if there are 30% or more plasma cells in marrow) Bone marrow L1 > 1% Renal insufficiency (not due to adult-acquired Fanconi syndrome or light-chain deposition disease) Hypercalcemia
Abnormalities in certain oncogenes and tumor suppresor genes develop at specific times: C-myc is an oncogene which normally promotes cell division and its expression allows for polyclonal plasma cell expansion. Its presence is required for the further development of plasma cell tumors. After this normal process of expansion, a loss of RB or p53 combined with K-ras overexpression allows for uncontrolled myeloma cell proliferation by increasing expression of autocrine IL-6. Oncogenes N-ras and K-ras are more often found in myeloma after bone marrow relapse. Changes in p53, a tumor suppressor gene which normally slows down cell division or causes cells to die at the appropriate time, are associated with spread to multiple organs.

Fibroblasts and macrophages in bone marrow stroma release interleukin-6 (IL-6) IL-6 has the following characteristics: · helps normal plasma cells grow · excess production of IL-6 by dendritic cells is an important factor in developent of plasma cell tumors · clinical studies have revealed that excess IL-6 productive may result from infection with Kaposi's sarcoma-associated herpes virus

Macrophage

Chromosomal abnormalities:

Chromosomal studies involving over 1400 patients have been done since 1959, with 1/3 of MM patients having clonal chromosomal abnormalities.

500 cases were reported including 166 with extensively presented karyotypes.

Aneuploidy is a common finding with multiple myeloma:

· hyperdiploidy mostly involves chromosomes 3,5,7,9,11,19, and 21

· hypodiploidy commonly affects chromosomes 13,8, and x

· A common specific abnormality among patients is the t(11;14)(q114;q32) translocation involving the bci-1 oncogene.

Deletion of chromosome 13 is not uncommon and carries a poor prognosis.

Lab Studies:

• Complete blood count to determine if the patient has anemia, thrombocytopenia, or leukopenia

• Comprehensive metabolic panel to assess a patient’s total protein, albumin and globulin, BUN, creatinine, and uric acid, which is high if the patient has high cell turnover or is dehydrated

• Serum protein electrophoresis, urine protein electrophoresis, and immunofixation

• Serum protein electrophoresis (SPEP) is used to determine the type of each protein present and may indicate a characteristic curve (ie, where the spike is observed).

• Urine protein electrophoresis (UPEP) is used to identify the presence of the Bence-Jones protein in urine.

• Immunofixation (IFIX) is used to identify the subtype of protein (ie, IgA lambda).

• A 24-hour urine collection for the Bence-Jones protein (ie, lambda light chains), protein, and creatinine

• Quantification of proteinuria is useful for diagnosis (>1 g of protein in 24 h is a major criterion) and for monitoring the patient’s response to therapy.

• Creatinine clearance can be useful for defining the severity of the patient’s renal impairment.

• Quantitative immunoglobulins (ie, immunoglobulin G [IgG], immunoglobulin A [IgA], immunoglobulin M [IgM])

• A minor diagnostic criterion for myeloma is the suppression of the nonmyelomatous immunoglobulin.

• Also, the level of myeloma protein (ie, M protein level), as documented by the immunoglobulin level, can be useful as a marker to assess the patient’s response to therapy.

• Beta2 microglobulin

• Beta2 microglobulin is a very strong predictor of outcome; some studies suggest it is more powerful than stage.

• Beta2 microglobulin is a surrogate marker for the overall body tumor burden.

• The level of beta2 microglobulin is increased in patients with renal insufficiency without myeloma, which is one reason that it is a useful prognosticator in myeloma. The prognosis of patients with myeloma and impaired renal function is reduced.

• C-reactive protein

• C-reactive protein (CRP) is useful for prognostication.

• The CRP is a surrogate marker of interleukin (IL)-6 activity. IL-6 often is referred to as the plasma cell growth factor.

• Check serum viscosity in patients with CNS symptoms, nosebleeds, or very high M protein levels.

Imaging Studies:

• Skeletal series

• Perform a complete skeletal series at diagnosis, including the skull (a very common site of bone lesions in multiple myeloma), the long bones (looking for impending fractures), and the spine.

• Diffuse osteopenia may suggest myelomatous involvement before discrete lytic lesions are apparent.

• The findings on this evaluation may be used to identify impending pathologic fractures, allowing physicians the opportunity to repair debilities and prevent further morbidity.

• Do not use bone scans to evaluate myeloma. Cytokines secreted by myeloma cells suppress osteoblast activity; therefore, no increased uptake is observed.

• MRI scan

• Findings on MRI scans of the vertebrae often are positive when plain radiographs are not.

• For this reason, evaluate symptomatic patients with an MRI scan to obtain a clear view of the spinal column and to assess the integrity of the spinal cord.

Procedures:

• Obtain bone marrow aspirate and biopsy samples to count the percentage of plasma cells in the aspirate (reference range <3%) and to look for sheets or clusters of plasma cells in the biopsy specimen.

• Cytogenetic analysis of the bone marrow may add significant prognostic information. Abnormalities of chromosome 13 (predominantly monosomy 13) predict a poor outcome. In addition, in MGUS, the presence of monosomy 13 may correlate with subsequent development of myeloma.

Histologic Findings: In patients with myeloma, plasma cells proliferate within the bone marrow, typically in sheets. Plasma cells are 2-3 times larger than typical lymphocytes; they have eccentric nuclei that are smooth (round or oval) in contour with clumped chromatin and have a perinuclear halo or pale zone. The cytoplasm is basophilic. Many descriptions of myeloma cells describe characteristic, but not diagnostic, cytoplasmic inclusions, which include Mott cells, Russell bodies, grape cells, and morula cells. Bone marrow examination reveals plasma cell infiltration, often in sheets or clumps. This infiltration is different from the lymphoplasmacytic infiltration observed in patients with Waldenström macroglobulinemia.

Staging: Staging is a cumulative evaluation of all of the diagnostic information garnered and is a useful tool for stratifying the severity of patients' disease. The staging system for myeloma is somewhat complex, but it is well correlated with outcome.

• Stage I involves all of the following:

• Hemoglobin greater than 10 g/dL
• Calcium less than 12 mg/dL
• Radiograph showing normal bones or solitary plasmacytoma
• Low M protein values (ie, IgG <5 g/dL, IgA <3 g/dL, urine <4 g/24 h)

• Stage II involves criteria that fit neither stage I nor stage III.
• Stage III involves any one of the following:

• Hemoglobin less than 8.5 g/dL

• Calcium greater than 12 mg/dL

• Radiograph showing advanced lytic bone disease

• High M protein value (ie, IgG >7 g/dL, IgA >5 g/dL, urine >12 g/24 h)

• Subclassification A involves creatinine of less than 2.0 g/dL.

• Subclassification B involves creatinine greater than 2.0 g/dL.

• Stage I has median survival of longer than 60 months, stage II is 41 months, and stage III is 23 months. Stage B disease has a significantly worse outcome (eg, 2-12 mo in 4 separate series).

Amyloidosis infiltrating the tongue in multiple myeloma. Reproduced with permission from the American Society of Hematology Slide Bank.

· Plasma cells are a subset of B cells, which are the producers of humoral immunity factors termed antibodies. Antibody molecules are composed of two polypeptide chains: a light chain and a heavy chain.

· Cleavage results in the production of Fab and Fc fragments; the Fab fragment is termed the Bence-Jones protein and is found in the urine of patients with myeloma.

· An individual plasma cell can produce antibody molecules of only a single immunoglobulin to combine with a single antigen.

· As such, a plasma cell is termed monoclonal.

· Most infections produce a polyclonal response, since multiple antigens are present on a single bacillus or virus and activate multiple plasma cells.

· Electrophoresis during infections demonstrates an increase in multiple types of proteins as a result of the multiple humoral and cellular products produced to combat the invading organism.

· However, if malignant transformation occurs in a single plasma cell, its clones produce only a single type of immunoglobulin, and electrophoresis demonstrates a monoclonal peak corresponding to this particular immunoglobulin.

· Infection, as well as collagen vascular disorders, rheumatoid arthritis, and ulcerative colitis, also can produce diffuse hypergammaglobulinemia.

· Waldenström macroglobulinemia, leukemia, lymphoma, and myeloma produce monoclonal peaks.

· If a monoclonal protein elevation is discovered in a patient and additional tests often do not reveal an underlying etiology, the condition is termed monoclonal gammopathy of undetermined significance.

· Most of these patients do not progress to multiple myeloma but must be followed up regularly to evaluate for an increase in monoclonal protein levels or the development of lytic bone lesions.

· The cause of multiple myeloma is unknown.

· Current theories involve chronic antigenic stimulation of a plasma cell, which results in transformation and the development of myeloma.

· However, once a plasma cell is transformed, it is known to produce innumerable clones, which spread hematogenously to other myelogenous areas.

· Once there, these neoplastic cells form sheets that replace the normal bone marrow.

· In addition, the myeloma cells produce osteoclast-stimulating factor, a cytokine that results in bone destruction.

· The plasma cell activating factor interleukin 6 is found within bone marrow, resulting in plasma cell proliferation.

· The osteoblastic response in myeloma tends to be suppressed, resulting in the severe demineralization and bone destruction characteristic of the disease.

· Secondary hypercalcemia is present

Durie and Salmon proposed the initial clinical staging system for multiple myeloma in 1975. Measured myeloma cell mass was correlated with 5 clinical features as follows:

• Hemoglobin level
• Serum calcium
• Number of bone lesions on a radiographic skeletal survey
• Immunoglobulin level
• Serum creatinine

Using these 5 features, a 3-stage system was proposed that divided patients into low, intermediate, and high myeloma cell burden.

• Stage I consists of all the following:
• Hemoglobin >10 g/dL
• Serum calcium <12 mg/dL
• Plasmacytoma to no lytic lesions on a skeletal survey
• Low immunoglobulin production (immunoglobulin G [IgG] <5 g/dL or immunoglobulin A [IgA] <3 g/dL)
• Stage II patients are defined as fitting into neither stage I nor stage III.
• Stage III patients demonstrate one or more of the following:
• Hemoglobin <8.5 g/dL
• Serum calcium >12 mg/dL
• More than one lytic bone lesion on a bone survey
• High immunoglobulin production (IgG >7 g/dL or IgA >5 g/dL)

Amyloid deposition due to the light chains is a frequent complication of multiple myeloma.
•The lytic lesion is believed to be due to activation of osteoclasts by cytokines liberated by the plasma cells. These cytokines include IL-1 and TGF-beta.
•IL6 may be produced primarily by stromal cells, activated by the plasma cells.
•IL6 levels are used to measure progress of the tumor.,

In constructing this staging system, researchers found that stage I patients had a median survival of 191 months, stage II patients survived from 11-54 months, and stage III patients survived from 5-34 months.

In the United States, approximately 10,000 persons per year die from the disease. Without treatment, most patients die in less than 1 year; with treatment, life expectancy may be extended 2-3 years.

Race: No racial predilection exists.

This is a view of the skull from above, after the scalp has been removed.
•Note the "punched out" circular, hemorrhagic lesions (some indicated by arrows).
•These are the tumor deposits in the bones of the skull.

rib

A higher power view of a deposit of malignant melanoma in bone marrow.
•Some of the typical, mature adipocytes of bone marrow are seen in this field.
•Most of the other cells in this image however, resemble each other.
•A typical cell can be seen at the tip of the black pointer.
•It is a large cell, with a nucleus that is placed at one end of the cell.
•The cytoplasm is abundant and stains blue (ie. basophilic).
•A paler relatively understained area is seen near the nucleus.
•These features typify a plasma cell.
•Careful examination of this field reveals that most of the cells in this field resemble that cell.
•Malignant myeloma is a tumor of plasma cells that arises usually in the bone marrow.

Bone marrow aspiration and biopsy reveals increased numbers of plasma cells (classically >30%, but may be only 10-30%), often forming clusters or sheets of cells replacing normal marrow elements. This results in anemia, leukopenia, and thrombocytopenia.

The growth factor IL-6 is produced in excess in MM and correlates with the proliferation of myeloma cells.

The plasma cells seen in the marrow can be mature - with classic PC features or immature - with prominent nucleoli.

Binucleate and multinucleate PCs can be seen.

Masses of immunoglobulin may form intracytoplasmic globules or Russell bodies.

Myeloma cells may also contain crystalline inclusions of immunoglobulin (below left).

Cells containing multiple immunoglobulin globules are known as Mott cells (below right).

The excessive production of an abnormal immunoglobulin is the second major characteristic of myeloma.

The abnormal Ig is most often IgG (50%) and sometimes IgA (25%), but rarely (<1%) IgM,IgD, or IgE.

Production of excess light chain is frequent and is excreted in the urine as Bence Jones proteins.

About 20-25% of cases produce only light chains which are often detectable only in the urine.

Fewer than 5% of myelomas are nonsecretory.

I mmunoglobulin filled cytoplasm may invaginate into the nucleus creating the appearance of an intranuclearinclusion (a Dutcher body).

Excess Ig in the peripheral blood may result in Rouleaux formation in which immunoglobulin coated RBCs cling together (resembling overlapping pennies).

The ESR may be increased secondary to hyperviscosity.

Hyperviscosity is most common with IgM, but can be seen with polymerization of IgA and IgG3.

M-proteins can interfere with clotting factors and fibrin polymerization, and can block aggregation by coating platelets.

roulaux formation

In approximately 75% of patients excess immunoglobulin light chain precipitates in renal tubules forming dense tubular casts and leads to tubular cell atrophy and destruction in a condition known as "myeloma kidney".

Although we think of Ig as being in plasma, remember that the majority of Ig is extravascular.

In about10% of myeloma patients a waxy substance known as amyloid is deposited in vessel walls and extravascular tissues secondary to excess light chain (usually l) production.

Amyloid stains lightly eosinophilic with H&E, red-orange with Congo Red, and is birefringent when polarized.

Amyloid stained with Congo red.

Polarized birefringent amyloid.

The EM appearance of amyloid is that of a mass of nonbranching linear fibrils of indeterminant length, 7-10 nm dia.

Accumulation of amyloid primarily in glomeruli, but also in vessels and interstium is a major cause of renal failure and death.

Heart failure is 2' to amyloid deposition in the conduction system.

GI tract infiltration can cause macroglossia, hemorrhage, malabsorption, diarrhea, and obstruction. Vascular damage results in amyloid purpura of the face (eyelids & periorbital tissue), neck and chest. Soft tissue accumulation may lead to the carpal tunnel syndrome.

The major diagnostic criteria for myeloma (any two are needed for the diagnosis) include:

- bone marrow plasmacytosis of > 30% of all marrow cells or masses of infiltrating plasma cells

- extraosseous plasmacytoma

- monoclonal gammopathy ( IgG > 35 g/L and IgA > 20 g/L )

- urinary light chain excretion of > 1g / 24 hours

Minor criteria (one or more of which together with one major criteria are needed for the diagnosis) include

- marrow plasmacytosis of < 30%

- lytic bone lesions

- evidence of a monoclonal protein but lessor amounts than above

- hypoglobulinemia of normal proteins

The prognosis for myeloma is highly variable, but left untreated, most patients survive only 6-18 months. Survival correlates with the extent of disease at diagnosis.

Myeloma Staging
Stage I	Stage II	Stage III
all criteria must be meet -Hgb >100g/L