Orbital Crystal-Storing Histiocytosis: A Clinicopathologic Study of 4 Cases.

The authors report the clinicopathological features of crystal-storing histiocytosis (CSH) that involved the orbit and conjunctiva and review published cases of CSH. Cases of histologically proven CSH were identified from archives at the Institute of Ophthalmology, London, and a retrospective review of clinical details and pathology was performed for cases between 1997 and 2017. Four cases of CSH were identified: 1 might have arisen from an inflammatory reaction to a silicone retinal buckle and 3 others occurred with localized B-cell lymphomas. Two patients presented with a conjunctival mass, and 2 had an orbital mass causing proptosis and hypoglobus. One case was associated with amyloid deposition and another had an earlier diagnosis of IgG4-related disease. In the patient without underlying lymphoma, the condition settled with removal of the explant and orbital mass, and the 3 with lymphoma underwent orbital radiotherapy with cessation of disease progression. All patients retained good vision. Ocular CSH is rare, can present in several ways, and should prompt investigation for an underlying lymphoproliferative disorder.