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Where do plasma cells come from?
B cells
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What is the most common plasma cell malignancy?
Multiple myeloma
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synthesize excess L or H chains or complete homogenous immunoglobulins
Monoclonal plasma cells
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When is the peak incidence of plasma cell disorders?
7th decade
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In a plasma cell disorder, how much of bone marrow consists of neoplastic cells?
>30%
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Describe pathological features of plasma cell disorders
- Osteolytic lesions in ribs,skull, sternum, vertebrae
- Bone marrow patchy, can have fibrosis
- Morphology of plasma cells varies
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Describe malignant plasma cells
- eccentricalyl located nucleus
- chromatin is clumped like clock faced chromatin
- perinuclear huff and pail area
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In multiple myeloma, describe bone destruction
- Begins in medullary cavity and works its way outword
- Pathology fx and punched out lesions occur and occasionally produce diffuse demineralization of the bone
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soft, red, gelatinous masses
MM
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perinuclear clearing due to prominent Golgi apparatus, eccentrically placed nucleus
neoplastic plasma cell associated with MM
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Dysregulated synthesis and secretion of immunoglobulin can lead to accumulation of intact or partially degraded Ig
MM
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Fiery red cytoplasm
Flame cell associated with MM
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multiple blue grapelike cytoplasmic droplets
Mott cell associated with MM
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Russell and Dutcher bodies
- Russell: cytoplasmic inclusions
- Dutcher bodies: nuclear inclusions
- Associated with MM
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What happens as MM progresses?
Invades soft organs: kidneys, lung, lymph nodes
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Describe cells you might see in MM
- Flame cells
- Mott cells
- Russell bodies
- Dutcher bodies
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Peripheral red blood smears may cause rouleaux formation from high levels of M protein
MM
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Neoplastic plasma cells may be seen in peripheral blood (making it look a little like leukemia)
MM
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Myeloma kidney MOA
Bence Jones proteins injure the kidney as some light chains are directly toxic to epithelial cells AND/OR BJ proteins combine with a urinary protein to produce tubular casts that obstruct the tubular luminal and induce an inflammatory reaction around the casts
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Clinical features of myeloma kidney
- Hypercalcemia and hyperuricemia
- Amyloidosis
- Light chain deposition dz
- Formation of concentric laminated casts which obstruct tubular lumen (By BJ proteins)
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What infections is a MM pt prone to?
Strep pneumo, staph aureus, and e coli
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What type of anemia is associated with MM and why?
normocytic normochromic as plasma cells crowd out RBC precursors
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What is the M component and where is it found?
- Monoclonal immunoglobulin in blood
- Comes from same clone
- Have high molecular weights
- Restricted to plasma and extracellular fluid because of
- weight
- Not typically in urine if the glomerulus is uninjured
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Light chains exreted in urine due to small size
BJ proteins (will be high in blood in cases of renal failure or if kidneys can't excrete fast enough)
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Most common symptomatic monoclonal gammopathy
MM
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Multiple nodules composed of abnormal plasma cells
MM
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What is significant abuot IL-6 in MM
IL-6 leads to proliferation and increased survival of plasma cells, therefore high levels are associated with a poor prognosis
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Which factors in MM are produce by neoplastic plasma cells? What do they do?
- MIP-1 and RANKL
- They activate osteoclasts, resorb the bone and break it down, giving rise to osteolytic lesions
- They contribute to increased calcium in the blood
- Calcium is ultimately filtered in the kidney
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What are karyotopic abnormalities with MM? What do they lead to?
- Deletions of 13q
- Translocation involving heavy IgH chain locus on 14
- FGFR3
- Cyclin D1: a cell regulatory gene on chromosome 11q13
- Cyclin D3: on chromosome 6p21
- cMAF: gene for transcription factor on chromosome 16q23
- MUM1/IRF4: a gene for
- an interferon regulatory factor
- They lead to cell being transcribed more rapidly, going through the cell cycle more rapidly, and proliferating more rapidly
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Plasma cell disorder not associated with skeletal lesions but with diffuse infiltratesof neoplastic cells into various tissues
Waldenstrom's macrolobulinemia
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Plasma cell disorder not associated with lytic lesions but with diffuse infiltratesof neoplastic cells into various tissues
heavy chain dz
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What do you need with the criteria to dx MM?
1 major or 3 minor
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What are the major criteria for MM?
- Marrow plasmacytosis >30%
- Plasmacytoma on bx
- M component, serum IgG >3.5; IgA >2, Urine >1 g/24 of BJ protein
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What are the minor criteria for MM?
- Marrow plasmacytosis of 10-30%
- M component present but less than in major criteria
- Lytic bone lesions
- Reduced nl serum Igs (<50% of nl)
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What are the four features of a localize plasmacytoma?
- single lesion
- skeletal lesions (can be readily bx)
- may have masses in the upper respiratory tract
- extra osseous lesions rarely disseminate
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Plasma cell disorder involving multiple organs with progressive demyelinating polyneuropathy
POEMS (osteosclerotic myeloma)
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What are clinical features of osterosclerotic myeloma?
- Poly neuropathy
- Organomegaly
- Endocrinopathy
- Skin changes
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What are the three major differences between MM and POEMS?
- POEMs has sclerotic, not lytic lesions, and there is neurological involvement.
- Onset is much younger than MM (51 opposed to 70s)
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Megakaryocytes may be large with hyperlobulated nuclei
POEMs
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What is a plasmacytoma and how is it related to MM?
- It is a solitary myeloma (single lesion of bone or soft tissue) associated with modest increase of proteins in the blood or urine
- Can be osseous or extraosseous, but the osseous variety commonly progresses to MM (extraosseous less likely to progress)
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Sheets of abnl neoplastic plasma cells that are extremely heterogenous
Plasmacytoma
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Describe MGUS
- no evidence of plasma cell dyscraise and minimal to no Bence JOnes protein in the urine
- Monoclonal protein <3g
- NO bone lesion, renal impairment, or hypercalcemia
- Bone marrow might be nl or have a slight increase in nl plasma cells
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What do you need to be careful of MGUS?
It can smolder and lead to MM, therefore have periodic assessment of B-J proteins and serum M component spikes
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AKA Waldenstrom’s macroglobulinemia
lymphoplasmacytic lymphoma
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B cell lymphoma of primarily males 60-70 yo
Lymphoplasmacytic lymphoma
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Tumor cells undergo terminal differentiation to plasma cells
Lymphoplasmacytic lymphoma
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H-S megaly with lymphadenopathy
Lymphoplasmacytic lymphoma
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Russell and Dutcher bodies
Inclusions associated with lymphoplasmacytic lymphoma
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Visual abnormalities due to hyperviscosity of RBCs (problems perfusing eyes and brain); neurologic abnl (HA, dizziness, stupor)
Lymphoplasmacytic lymphoma
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Bleeding problems due to complexes between macroglobulins and platelets
Lymphoplasmacytic lymphoma
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Plasma cell disorder involving BM, LN, liver and spleen but WITHOUT bony erosions
Lymphoplasmic lymphoma
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Hemolysis by cold agglutinins : IgM Abs binding to RBC at temperatures below 37C
Lymphoplasmacytic lymphoma
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Raynau'd phenomenon and cold urticaria
Lymphoplasmacytic lymphoma
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BM sparse with plasma cells, lymphocytes, and plasmacytoid lymphocytes
Lymphoplasmacytic lymphoma
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Hyperplasia of mast cells
Lymphoplasmacytic lymphoma
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Prognosis of someone with Lymphoplasmacytic lymphoma
Incurable progressive, median surviva is 4 years
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What is the difference between IgG and IgA in heavy chain dz?
- IgG: diffuse, lymphadenopathy with h-s megaly
- IgA: prediliction for SI, respiratory tract
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Monoclonal group of plasma cells secrete free L chains
Immunocyte-associated amyloidosis
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L chains pressed and deposited as amyloid that can be deposited in a lot of different organs
Immunocyte-associated amyloidosis
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