Localized ocular crystal-storing histiocytosis and associated lymphoma - Report of two cases and review of literature

PURPOSE: To add to the existing yet limited body of knowledge around crystal-storing histiocytosis (CSH) with two case reports of localized ocular CSH and associated mucosa-associated lymphoid tissue (MALT) lymphoma involving the lacrimal and orbital soft tissues without underlying systemic lymphoproliferative disorders and to provide a literature review of all cases of CSH with associated ophthalmic findings reported to date. OBSERVATIONS: A 62-year-old male presented with a one-year history of right greater than left upper eyelid swelling and epiphora. Ophthalmic exam and computed tomography (CT) head scan revealed bilateral soft tissue masses superior to the globe encasing the supraorbital artery with poor margins from the superior rectus muscle. A biopsy of the lesion showed low grade B-cell lymphoma and associated CSH with lymphoma making up the bulk of the tumor and with CSH comprising a minor component of the overall tumor volume. Further investigations did not show any evidence of systemic lymphoproliferative disorders. He received local irradiation of orbits, which resulted in complete resolution of disease. An 85-year-old female with no significant past ocular history referred to ophthalmology services for an incidental finding of an enlarged left lacrimal gland on a CT head scan. Ophthalmic exam and subsequent magnetic resonance imaging (MRI) demonstrated an enlarged left lacrimal gland. A biopsy of the lesion showed MALT lymphoma associated with CSH. In this case, CSH comprised the bulk of the clinical mass rather than lymphoma. Following negative systemic investigations, she received a short course of localized radiotherapy with a 50% regression of disease seen on follow-up CT scan. CONCLUSION AND IMPORTANCE: These two cases demonstrate a spectrum of morphology associated with CSH. In addition, they show that although localized ocular CSH is rare, CSH should be considered in the differential of an orbital mass and should lead to consideration of further investigation for systemic lymphoproliferative disorders.