Multiple Myeloma

Question 1

What is the neoplastic cell in multiple myeloma?

Answer 1

Plasma cells; produce immunoglobulins

IgG (52%)

Question 2

What is the most common primary malignancy of bone?

Answer 2

Multiple myeloma; blacks twice more common; age >40yo; males twice more common

Question 3

What is the survival rate in multiple myeloma?

Answer 3

5-year of 30%; 10 year of 11%;

worse prognosis is in renal failure; best prognosis if solitary plasmacytoma

Question 4

What are the diagnostic criteria for multiple myeloma?

Answer 4

Must have 1 major and 1 minor or 3 minor
A] Major
   1) biopsy confirmation
   2) >30% plasma cells
   3) IgG >3.5g/dL, IgA >2g/dL
   4) IgA >1g/24h in urine or bence jones protein
B] Minor
   1) 10-30% plasma cells in marrow
   2) decreased serum IgG
   3) "punched out" lesions on imaging

Question 5

What causes the “punched out” lesions of multiple myeloma?

Answer 5

Osteoclastic resorption via RANKL, IL-6 and MIP-1 alpha

Question 6

What additional labs should be ordered in multiple myeloma?

Answer 6

CBC- anemia
BMP- elevated Cr, hypercalcemia
ESR- elevated
SPEP- M spike (50% IgG, 25% IgA)
UPEP- Bence Jones protein (only detects light chains)
UA- porteinuria

Question 7

Histology of eccentric, hyperchromic nucleus could indicate what malignant disease of bone?

Answer 7

multiple myeloma; will stain CD38+

Question 8

What is the treatment for multiple myeloma?

Answer 8

Multiagent chemo, steroids and bisphosphonates are mainstay
Plasmacytoma- radiation of (45-50 Gy)
Stabilization and radiation for impending or complete fx