Plasma Cell Myeloma and Other Plasma Cell Dyscrasias

Abstract

Overview of Plasma Cell NeoplasmsPlasma cell neoplasms encompass a group of diseases with varying clinical manifestations but with at least one common feature, the production by neoplastic plasma cells with a monoclonal immunoglobulin protein (M-protein, or paraprotein). These diseases include plasma cell myeloma (PCM) (and its clinical variants), solitary plasmacytoma of bone, extraosseous plasmacytoma, and the monoclonal immunoglobulin deposition diseases (primary amyloidosis and monoclonal light and heavy chain deposition diseases) (Fig. 19-1). The clinical variants of PCM now recognized by the World Health Organization (WHO) are symptomatic PCM, asymptomatic PCM (also known as smoldering PCM), nonsecretory myeloma, and plasma cell leukemia (PCL).PCM will be the primary focus of this chapter, but other plasma cell neoplasms enter into the differential diagnosis. Solitary plasmacytoma of bone lacks evidence of systemic dissemination or diagnostic features of PCM, but can undergo progression to myeloma. Extraosseous plasmacytoma is restricted to extramedullary tissues, most frequently the upper respiratory tract, usually only produces symptoms related to its mass effect, and rarely progresses to PCM. Primary amyloidosis is the deposition of immunoglobulin light chain aggregates that show apple-green birefringence on a Congo red stain (i.e., AL amyloid) and usually sparse clonal plasma cell proliferations. Clinical manifestations of the effects of amyloid on producing organ or tissue dysfunction include nephrotic syndrome, heart failure, malabsorption, peripheral neuropathy, and bleeding disorders. The related light and heavy chain deposition diseases are due to deposition of non-birefrigent immunoglobulin and produce a similar range of effects although their ultrastructural appearance is different than amyloid. These include the immunoglobulin "heavy chain deposition" disorders which