6.8/6.9 Plasma Cell Disorders, Langerhans Cell Histiocytosis

Question 1

What is Multiple Myeloma

Answer 1

Proliferation of plasma cells in the marrow
Most common primary malignancy of bone
High serum IL-6 stimulates plasma cell growth and immunoglobulin production

Question 2

Clinical features of Multiple Myeloma

Answer 2

Think of this as many substances that are overproduced by the plasma cells:

Osteoclast activating factor: through RANK receptor on osteoclasts leads to bone destruction, lytic “punched out” lesions in vertebrae and skull, increased risk of fracture

Antibody: Elevated serum protein from a monoclonal Ig production leading to an M spike on protein electrophoresis, generally IgG or IgA; increased risk of infection from lack of Ab diversity (infection most common cause of death); rouleaux formation of RBC’s on smear

Light chain: primary AL amyloidosis; proteinuria from light chain “Bence Jones protein;” deposition in kidney tubules risk of renal failure “myeloma kidney”

Question 3

Elderly patient is found to have an M-spike on serum protein electrophoresis. Found to have no lytic bone lesions, no hypercalcemia, no AL amyloid or Bence Jones proteins. Likely Dx?

Answer 3

MGUS (type of plasma cell dyscrasia)
Monoclonal Gammopathy of Undertermined Significance
Very few go on to develop multiple myeloma

Question 4

What is Waldenstrom Macroglobulinemia?

Answer 4

B cell lymphoma with monoclonal IgM production
Clinical: generalized LAD, lytic bone lesions absent, increased serum protein with M spike, Visual and neurologic deficits (retinal hemorrhage and stroke), IgM (being large) causes serum hyperviscosity, bleeding (hyperviscosity leads to poor platelet function)
Treat with plasmaphoresis

Question 5

What disorder is known for Birbeck granules and what do they look like?

Answer 5

Langerhans cell histiocytosis

Look like tennis rackets on electron microscopy

Question 6

What is Langerhans Cell Histocytosis

Answer 6

Proliferation of Langerhans cells–dendritic cells in the skin

Question 7

What cell markers are assoc. c langerhans cell histiocytosis?

Answer 7

CD1a+ and S100

Question 8

What are the 3 diseases under Langerhans Cell Histiocytosis?

Answer 8

Lettere-Siwe Disease: malignant, skin rash, cystic skeletal defects in infant (less than 2yo), rapidly fatal

Eosinophilic Granuloma: benign, pathologic fracture in adolescent, skin not involved, biopsy show mixed inflammatory cells including numerous eosinophils

Hand-Schuller-Christian Disease: malignant, scalp rash, lytic skull defects, diabetes insipidus, exophthalmos in a child