Plasma cell disorders/ dyscrasias

Question 1

Plasma cells

Answer 1

terminally differentiated B cells

Function: Antibody secretion
2 heavy chains : u y a d e
2 light chains: k ^

Morphologically: have clock face chromatin, very blue cytoplasm

Question 2

Plasma cells and pathology

Answer 2

Reactive conditions: chronic infections (h pylori gastritis, osteomyelitis, endometritis, HIV)
Autoimmune processes (lupus, hepatitis)

Neoplastic conditions: 
-monoclonal gammaopathy of undetermined significance (MGUS)
- Plasmacytoma
- Lymphoplasmacytic lymphoma
Amyloidosis
- Multiple meylopa

Question 3

Reactive vs neoplastic proliferations, how to tell them apart

Answer 3

CLONALITY!
Clonality is evidence of neoplasia

Plasma cell: can look for monoclonal antibodies in the serum or urine, light chain restiction in cell cytoplasm (kappa vs lambda) by flow cytometry or immunohistochemistry, immunphenotypic aberrancy (CD56 on plasma cells)

Question 4

M proteins

Answer 4

M protein= Monoclonal antibodies
Serum: intact immunoglobulins and/or free light chains
Urine: Abs may be filtered when kidney damage, free light chains which are small can pass thru the glomerulus
Bence jones proteins= free light chains
Identification with electrophoresis and sensitive immunoassays

Monoclonal gammaopathy: presnece of an M protein, may be present in plasma cell disorders and B cell lymphomas, rarely seen in reactive states

When to order an SPEP/UPEP: Myeloma or lymphoma, neuropathy, anemia, osteolytic bone lesions/ pathologic fractures, unexxplained renal failure, hyperclacemia

Question 5

Monoclonal gammopathy of undeteremined significance

Answer 5

most common form of monoclonal gammopathy, seen in elderly
need to have an M protein (less than 3 g/dL), <10 % clonal plasma cells in the bone marrow, no myeloma-related end organ damage
no symptoms

Considered a benign plasma cell proliferation, but a precursor lesion, 25% develop malignant transformation over 10-20 years, dependent on type of M protein
IgG or IgA- 1% / year transform to myeloma
IgM: 1.5 %/year transform to lymphoplasmacytic lymphoma.waldenstroms macroglobulinemia

Indefinite follow up, monitor M protein

Question 6

Multiple myeloma

Answer 6

Most common plasma cell neoplasm, malignant, M>F, AA>W, 50-70 yo

Diagnostic criteria:
Clonal plasma cells> 10 % clonal marrow plasma cells OR biopsy proven bone or extramedullary plasmacytoma
WITH end organ damage: hyper calcemia (RANK activivation of osteoclasts), renal insufficiency (Bence jones light chain proteinuria), anemia, bone disease, amyloidosis, Anemia (marrow replacement by plasma cells)

Prognosis: incurable 8-10 years for good risk, ANti CD38

Immunosuppressed

Question 7

Plasmacytomas

Answer 7

Localized growth of monoclonal plasma cells, may be seen in multiple myeloma or as a distinct entity, need radiation

Question 8

Lymphoplasmacytic lymphoma

Answer 8

Lymphoma with plasmacytic differentiation (B cells and plasma cells are neoplastin) involving the bone marrow and the lymph nodes
IgM paraprotein

WALDENSTROMS MACROGLOBULINEMIA (visual, nueor involvment, reynaid phenomenon, bleeding

Question 9

Amyloidosis

Answer 9

Primary usually due to multiple myeloma, hereditary, localized may be associated with lymphoma
You can tell it by apple gree congo stain