COMPARISON OF BONE-MARROW SECTIONS, SMEARS AND IMMUNOHISTOLOGICAL STAINING FOR IMMUNOGLOBULIN LIGHT-CHAINS IN THE DIAGNOSIS OF BENIGN AND MALIGNANT PLASMA-CELL PROLIFERATIONS

Bone marrow specimens from 118 patients with clinical suspicion of mul tiple myeloma were studied to assess the diagnostic reliability of his tological and cytological criteria. Plasma cell clonality was assessed by demonstrating light chain restriction. In most cases of multiple m yeloma, the classical cytological and histological criteria were found . In eight cases in which the marrow contained less than 10% of plasma cells. there was discordance between the light microscopic and immuno histochemical findings. In six cases without evidence of multiple myel oma and with polyclonal plasma cells in bone marrow, abnormal plasma c ells resembling a malignant proliferation were found. These findings i ndicate that comparison of histological and cytological results with i mmunohistological studies for immunoglobulin light chains in bone marr ow biopsy sections can be helpful in the evaluation of patients with a suspicion of multiple myeloma and when the marrow contains less than 10% of plasma cells.