Pathology of multiple myeloma

Multiple myeloma (MM) and other plasma cell proliferative disorders (PCPD) are a group of systemic diseases which share as a unifying feature the presence of clonal plasma cells. As described in previous chapters, bone marrow is the most common tissue involved, but the neoplastic plasma cells may be found in virtually any tissue/organ. While serum protein electrophoresis and free light chain analysis are essential in early detection and follow-up, the pathologic diagnosis of MM and other PCPD is made on the bone marrow aspirate and biopsy specimen [1]. The goal of the pathologic examination of the bone marrow is to: (a) quantify bone marrow plasma cells (necessary WHO criteria for the diagnosis of MM); (b) establish PC clonality; (c) distinguish MM from lymphoplasmacytic lymphoma (LPL) and other B-cell lymphomas with plasmacytic differentiation; (d) analyze prognostic factors; (e) detect amyloid deposits; and (f) detect other potential pathologic processes, in lymphoid and myeloid compartments.