Reclassification of intraocular reticulum cell sarcoma (histiocytic lymphoma). Immunologic characterization of vitreous cells.

Systemic and orbital reticulum cell sarcomas (RCSs) have been shown to be derived from lymphocytes, not reticulum cells or histiocytes, by immunologic and cytochemical characterization. Unfortunately, until now it has not been technically possible to study intraocular RCS. We have been able to immunologically characterize a primary intraocular RCS in a patient with chronic lymphocytic leukemia (ie, Richter's syndrome), establishing its origin from B lymphocytes. A review of the clinical course of such tumors indicates that primary intraocular non-Hodgkin's lymphoma is usually a manifestation of a systemic neoplasm of the immune system.