Myeloma with Russell bodies

Abstract

Immunoglobulins are synthesized within the ribosomes of plasma cells. They are then transported to the Golgi apparatus, where they are processed and packaged into secretory granules that then fuse with the outer cell membrane. In certain monoclonal gammopathies and in occasional instances of reactive plasma cell hyperplasia associated with intense immunoglobulin production, immunoglobulins may precipitate within the plasma cell, forming inclusion bodies. These inclusions may appear as multiple pale-blue intracytoplasmic globules, often resembling a bunch of grapes. Plasma cells containing such intracytoplasmic globules are referred to as Mott (or morula) cells. In some instances, plasma cells contain a single pale-bluish intranuclear globular inclusion that is referred to as a Dutcher body. The single dark-red hyaline intracytoplasmic (or rarely intranuclear) spherules that are found in plasma cells are called Russell bodies. Although most commonly found in patients with multiple myeloma (as in the case shown here), Russell bodies can also be found in instances of sustained immunologic stimulation and/or inflammation in association with hypergammaglobulinemia. The bone marrow in this particular instance was densely infiltrated by abnormal plasma cells, a large proportion of which contained a single large intracytoplasmic Russell body that can be seen displacing the nucleus to the periphery of the cell (see Image 1). Immunoperoxidase stains revealed the presence of a monoclonal IgG with lambda light-chain restriction. Ultrastructurally, each Russell body represented a large, electron-dense inclusion that was found within the distended endoplasmic reticulum (see Image 2). Image 1. Image 2.