A Case of Non-secretory Myeloma with Crystal-storing Histiocytosis

Abstract

Crystal-storing histiocytosis (CSH) is a rare event observed in association with lymphoproliferative diseases, and mainly occur in plasma cell dyscrasias. It is presumed to be an intra-lysosomal accumulation of the secreted paraproteins. Crystal formation can be seen inside histiocyte-like cells with phagocytosed crystalline inclusions in the bone marrow and extramedullary sites. CSH is a rare morphological entity with poor prognostic implications and may be confused with Gaucher or pseudo-Gaucher cells. Herein we report a case of non-secretory myeloma associated with CSH showing a poor clinical course. A 79-yr-old male presenting with dizziness was evaluated in hematology department for anemia. Laboratory tests revealed Hb of 4.9 g/dL and β2-microglobulin of 21,000 ng/mL (reference range, 0-370). Presence of monoclonal protein was not detected on protein electrophoresis and immunofixation in serum and urine. However, serum free light chain assay showed an increased kappa-light chain level of 126 mg/L (reference range, 3.3-19.4) resulting in an increased kappa/lambda ratio. The bone marrow touch print showed numerous plasma cells and crystal-laden histiocytes and immunohistochemical stainings on bone marrow biopsy revealed positivity for CD38, CD56 and kappa in the plasma cells and CD68 and kappa in crystal-laden histiocytes.

Chromogenic in situ hybridization for the detection of lambda and kappa immunoglobulin light chains as a potential auxiliary diagnostic technique in canine plasmacytomas

“…Therefore, the possibility that these tumors produce little-to-no amount of light chains is a likely hypothesis that needs to be further investigated. In humans, oligosecretory and non-secretory multiple myelomas have been described, 14,20,22,29,31,35 and there are rare reports of cutaneous PCTs negative for both light chains. 3 CISH detected light chain expression in 2 of 9 (22%) DLBCLs, with a multifocal and rather less intense staining than PCTs, which may be interpreted as indicative of the relatively low levels of light chain mRNA expression in lymphoma cells compared with neoplastic plasma cells.…”