Crystal storing histiocytosis forming a mass lesion in temporal lobe

Crystal storing histiocytosis is a disorder characterized by local or diffuse infiltration of histiocytes containing crystalline inclusions. This entity has been reported in several organs, however the involvement of the central nervous system (CNS) is extremely rare and to date only 7 cases of crystal storing histiocytosis (CSH) of CNS have been reported in the English literature. More than 90% patients with CSH had an underlying lymphoproliferative or plasma cell disorders, especially multiple myeloma, lymphoplasmacytic lymphoma or monoclonal gammopathy. Radiologically and intraoperatively, CSH may mimic an infectious process or neoplasm, hence its histopathological confirmation is important to facilitate appropriate treatment. In this report, we describe an additional case of crystal storing histiocytosis in a 48 year old female who presented with a mass lesion in the right temporal lobe of the cerebrum.