Azurophilic granules in myeloma cells

Abstract

The neoplastic cells of multiple myeloma (plasma cell myeloma) show a wide range of cytological abnormalities. These include cytoplasmic inclusions composed of immunoglobulin, which may be either crystalline or globular, the latter either clearly in the cytoplasm (Russell bodies) or invaginated into the nucleus (Dutcher bodies). A distinctive type of rod-shaped azurophilic inclusion does not represent immunoglobulin but rather is lysosomal in origin [1].In this patient with immunoglobulin G kappa myeloma a large proportion of the myeloma cells contained azurophilic granules, sometimes round and sometimes irregular (image). By analogy with the azurophilic Auer rod-like inclusions with similar staining characteristics that may be observed in myeloma [1,2], it is likely that these inclusions are of lysosomal origin. In one reported case, the granules were positive for acid phosphatase and weakly positive for alpha naphthyl butyrate esterase; on ultrastructural examination they were distinct from the endoplasmic reticulum and were considered likely to be vacuoles of the lysosomal system [3]. Azurophilic cytoplasmic granules have been observed in association with both kappa [4] and lambda [3] light chains.

Clinical significance of granule‐containing myeloma cells in patients with newly diagnosed multiple myeloma

“…The significance of the presence of cytoplasmic granules in myeloma cells is poorly understood. The GM cells are considered to be detectable infrequently because the study about large number of cases with the GM cells has not been demonstrated, and only several cases with cytoplasmic granules in myeloma cells were reported . In our study, 20.5% of MM patients displayed cytoplasmic granules, and hence we speculated that GM cells could be detected occasionally.…”

“…Granules are detected in the cytoplasm of myeloma cells by May‐Giemsa staining in some cases. Since the first identification of granule‐containing myeloma cells by Steinmann, several case reports about granule‐containing myeloma have been published . However, the clinical features of granule‐containing myeloma cells have not yet been elucidated.…”

Unusual Hypergranular Myelomatous Plasma Cells

“…Cytoplasmic crystalline inclusion bodies in neoplastic plasma cells are not a rare event. activity, also demonstrated in our case [1][2][3]. Its prognostic values has not been investigated because of its rarity.…”