Introduction:
Crystal storing histiocytosis (CSH) is a rare entity characterized by the intra-lysosomal accumulation of crystals composed of immunoglobulin light and/or heavy chain fragments enriched in Ig variable regions within histiocytes [1]. In 90% of CSH, an underlying B lymphoproliferative or plasma cell disorder is present [2]. The pathophysiology of CSH seemed to be associated with the type of light chain rather than the heavy chain [3]. Some mutations in variable sequences may induce crystallization of immunoglobulins and resistance from lysosome clearance leading to the formation of crystal storing inclusions and secondary granulomatous lesions. Bing-Neel syndrome is a rare and probably underdiagnosed neurologic complication of Waldenström macroglobulinemia (WM) with infiltration of central nervous system (CNS) by malignant lymphoplasmacytic cells [4-5-6].
Herein, we report the case of a 69-year-old Caucasian male presenting atypical manifestations of a marginal zone lymphoma with plasmacytic differentiation and IgM paraprotein complicated by CSH and neurological impairment similar to BNS which is known as a complication of Waldenstöm macroglobulinemia.