L10a

Mr. Thompson is  a 75 year old African American gentleman who presents to your office with bone pain and fatigue. He has been getting sick a lot lately which he insists is quite unusual.  His lab results show that he has anemia and hypercalcemia. It is also suggestive of kidney damage (elevated BUN/Cr). 

A bone marrow biopsy/aspirate are shown below:

What is the predominant cell type seen above? What type of neoplasm is this?

• plasma cell
• multiple myeloma

Why is there hypercalcemia?

• lytic bone lesions from osteoclast activation by neoplastic cells (RANKL)

What is monoclonal gammopathy? What type would you expect to see? 

• proliferation of one type of immunoglobin - 50% IgG
• lack of variety in Ig makes patients more susceptible to illness

Do you expect to see a hyperviscosity syndrome like you do in Waldenstrom macroglobulinemia?

• only if it is an IgM monoclonal gammopathy (rare) - IgM = pentamer

How is this illness similar/different from Waldenstroms? 

• 25% BJ proteins (W); 80% MM
• no lytic lesions (W)
• lymphocytes (W), plasma cells (MM)
• IgM only (W), monoclonal gammopathy of any type - IgG most common (MM)

Why does he have kidney problems?

• light chain deposition = amyloidosis
• most common in tubules - myeloma kidney (DCT/CD)
• also seen in glomerulus
• deposition of protein ---> loss of function

Where are lytic lesions typically found?

• vertebrae