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.