Plasma Cell/Histiocytic Disorders

Question 1

Multiple Myeloma

Answer 1

Increased plasma cells in the bone marrow.

• Increased IL-6 (growth factor for plasma cells)
• Bone lesions/hypercalcemia (plasma cells activate osteoclasts)
• Increased serum immunoglobulin (M spike: IgG or IgA).
• Primary amyloidoses: light chain deposits into tissues and forms AL amyloid
• Erythrocyte rouleaux formation (M protein increases stickiness).

Question 2

What are some common things seen in histiocytic disorders?

Answer 2

Neoplastic proliferation of Langerhans cells (dendritic cells of skin/mucosa)

Birbeck granules (tennis racket)

CD1a and S-100 proteins.