Multiple Myeloma Flashcards
what is a multiple myeloma?
neoplasm of antibody secreting B cells (plasma cells)
what are plasma cells?
terminally differentiated B cells that secrete antibodies
immunophenotype of plasma cells
CD19+, CD138+, CD56-
where do normal plasma cells reside?
lymph nodes and bone marrow
morphologic features of normal plasma cells
eccentric nuclei, clumped clockface nuclear chromatin, perinuclear clear zone for golgi, abundant gray cytoplasm
CD138
syndecan. indicative of plasma cells
CD56
NCAM. cell adhesion molecule expressed by neoplastic plasma cells. allows them to home in on bone marrow rather than accumulate in medullary zone of lymph nodes
epidemiology of multiple myeloma
common in african americans, affects age 70+,
clinical features of multiple myeloma
multifocal, osteolytic lesions and successive fractures, trabecular destruction leading to hypercalcemia, anemia via marrow destruction and renal failure (EPO)
where are the osteolytic lesions of multiple myeloma most commonly found?
axial skeleton, particularly the vertebrae/ribs/skull
soft tissue tumors of multiple myeloma
plasmacytomas. commonly found in vertebral column, which is an emergency since they cause cord compression
morphology of multiple myeloma
hyper cellular marrow: clusters or sheets of monoclonal plasma cells, replacement of marrow elements, destruction and resorption of bone. VARIABLE MORPHOLOGY
flame cell
IgA expressing plasma cells with pink border
Mott cells
look bubbly. have accumulated globules of intracytoplasmic monoclonal Ig
M protein/paraprotein
unique homogenous monoclonal Ig secreted by plasma cells
MGUS
monoclonal gammopathy of undetermined significance. low grade asymptomatic proliferation that isn’t clearly neoplastic. most likely won’t progress to multiple myeloma, but some do
what can the kidney filter in terms of Ig?
light chains can pass through the glomerulus
difference in Ig production of normal and neoplastic plasma cells
neoplastic cells: unbalanced production–> excess light or heavy chains.
Bence Jones Protein
excess light chains in urine. can be used to diagnose multiple myeloma
most common paraproteins
IgG and kappa
why are patients with multiple myeloma immunodeficient and anemic?
increase in monoclonal Ig leads to a decrease in other types. Same goes for types of cells in the bone marrow
name for immunodeficiency of multiple myeloma
humoral immune paresis
two main causes of deaths in MM patients
immunodeficiency (recurrent bacterial infections) & renal failure (myeloma kidney)
myeloma kidney
due to cast nephropathy, proximal tubulopathy, hypercalcemia, amyloidosis
cast nephropathy
excess light chains settle out in aggregates in the distal nephron, forming obstructive casts
consequences of paraprotein
serum hyper viscosity with rouleaux formation. causes vascular complications like visual impairment, neurological problems, and bleeding. Cryoglobulinemia (Raynauds phenomenon), amyloidosis.
MM prognosis
variable (1-many years) without a cure
