Plasma Cell Dyscrasias - Harrington Flashcards

1
Q

What is the characteristic nuclear morphology seen histologically in plasma cells?

A

Clock-face chromatin

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2
Q

How do we differentiate reactive vs. neoplastic conditions with B cells?

How might this be detected?

A

Clonality -> gives evidence of neoplasia

Methods: monoclonal antibodies in the urine, light-chain identification via flow cytometry of immunohistochemistry, immunophenotypic aberrancy (example: CD56 on plasma cells)

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3
Q

Define: Bence Jones Protein

A

free light chains, may be found in the urine

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4
Q

What is the most common plasma cell neoplasm?

A

Multiple myeloma

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5
Q

Describe the epidemiology of multiple myeloma

A

15% of all heme malignancies in the US

Males > Females

AAs > Caucasians

50-70 y/o (median 68-70)

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6
Q

Name the three major diagnostic criteria for multiple myeloma

A
  1. Clonal plasma cells
  2. M protein
  3. End organ damage
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7
Q

What end-organ damage is seen with multiple myeloma? (Hint: mnemonic)

A

CRAB

hyperCalcemia

Renal insufficiency

Anemia

Bone disease

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8
Q

Why is it important to obtain electrophoresis of both the urine **and **the serum when diagnosing multiple myeloma?

A

99% of myelomas have M protein or Bence Jones protein, but they don’t always appear together nor in both locations.

60-70% have serum M protein **and **Bence Jones proteins

20% have only Bence Jones proteins

In the setting of kidney disease, the Bence Jones proteins may only appear in the urine (due to hyperfiltration of the serum)

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9
Q

What is the most common site of lytic bone lesions in multiple myeloma?

A

Vertebrae (66%)

Ribs (44%)

Skull (41%)

Pelvis (28%)

Femur (24%)

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10
Q

Name some common forms of end organ damage seen in multiple myeloma

Which is the most common cause of death in MM?

A

Lytic bone lesions (bone pain, pathologic Fx, osteopenia)

Hypercalcemia (secondary to bone resorption)

Renal insufficiency (direct nephrotox, tubular casts, amyloidosis, etc)

Anemia (rouleaux = stacks/aggregates of RBCs, renal disease, bone marrow invasion)

Immunosuppression (normal Ig suppressed by M proteins -> recurrent infections -> most common cause of death)

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11
Q

Describe the general prognosis of multiple myeloma

What is the general treatment approach?

A

Incurable

Median **treated **(!!!) survival: 4-6 years

treatment: systemic chemotherapy and two (“tandem”) autologous bone marrow transplants

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12
Q

What is a plasmacytoma?

What is its relationship to MM?

A

Localized growth of monoclonal plasma cells

It may be associated with MM, or appear as a distinct entity

By iteself: no clonal expansion in bone marrow, +/- M protein

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13
Q

What is the general treatment approach for plasmacytoma?

A

Localized: radiation

Systemic (w/ MM): chemo + BMT

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14
Q

Where do plasmacytomas usually occur?

A

Solitary plasmacytoma of bone

Extramedullary plasmacytoma (80% in URT)

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15
Q

What is Waldenstrom’s macroglobulinemia?

A

Characteristic of lymphoplasmacytic lymphoma

  • Visual/neurologic impairment
  • Cryoglobulinemia
    • Raynaud phenomenon
    • Bleeding
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16
Q

What is Lymphoplasmacytic lymphoma?

How is the paraprotein seen in this condition different than others?

A

Lymphoma with plasmacytic differentiation

IgM paraprotein (others have IgG paraprotein)

17
Q

What is the most common form of monoclonal gammopathy?

Describe it

A

Monoclonal Gammopathy of Undetermined Significance (MGUS)

MGUS is considered benign, but 25% develop malignant transformation over the next 10-20 years (most often MM), requiring frequent follow-up for life

18
Q

Describe the diagnostic criteria of MGUS

A

definitely called “undetermined significance” for a reason…

<3 g/dL serum M protein

<10% clonal plasma cells in bone marrow

No myeloma-related end-organ damage

19
Q

Apple-green birefringence on Congo Red Stain is indicative of what?

A

Amyloidosis

20
Q

What is Amyloidosis?

What is the most common form?

A

Diseases characterized by deposition of amyloid (an extracellular proteinaceous misfolded substance)

Most common form: amyloid light chain (from B cells and plasma cells)

21
Q

Name some common deposition sites of Amyloidosis and the basic consequences of each

A
  • Heart: conduction abnormalities
  • Kidney: glomerular damage, nephrotic syndrome
  • Liver: hepatomegaly
  • Nerves: polyneuropathy
  • GI tract: malabsorption, diarrhea
  • Tongue: macroglossia