Clinical significance of bone marrow biopsy and plasma cell morphology in MM and MGUS.

Multiple myeloma (MM) is characterized by plasma cell infiltration in the bone marrow, suppression of normal haematopoiesis, destruction of bone, renal failure and recurrent infections. The extent of organ involvement, severity of complications, drug sensitivity and therefore the clinical course differ widely among patients. Specific and reliable laboratory examinations and especially morphology including both biopsy and aspirations are required to evaluate its aggressivity and extent. In this review of MM and its variants we emphasize the impact of morphology on the diagnostic and prognostic approach to MM and MGUS, and on the planning and monitoring of appropriate therapy.