OrthoNet

Myeloma

- malignant plasma cell tumor originating from marrow that usu presents with multiple bony lesions
- males > females; presents in 6th decade with pain usu involving vertebrae, ribs or pelvis

Labs:
- anemia, elevated serum Ca, plasmocytosis in bone marrow (>30%)
- serum electrophoresis - globulin spike
- immunoelectrophoresis - high levels of monoclonal immunoglobulins (M components) in serum
- monoclonal light chains in urine (Bence Jones proteinuria)

Xrays:
- multiple or single small, well-circumscribed ‘punched-out’ lytic lesions
- little or no reaction by surrounding bone but endosteal scalloping & medullary expansion
- with long bone involvement, may be cortical destruction with soft tissue mass

Histology:
- tightly packed plasma cells with eccentrically located nucleus, abundant pink cytoplasm & pale-stained juxtanuclear halo
- nodular foci or broad areas of amyloid deposits with no background stroma
- intracytoplasmic inclusions (Russell bodies)

Treatment:
- chemotherapy & radiation (for solitary lesions)
- internal fixation for pathologic or impending pathologic #s