Reticulum cell sarcoma (histiocytic lymphoma) of the orbit.

The clinical and pathologic features of 13 patients with biopsy-proven reticulum cell sarcoma of the orbit are reviewed. All of the patients were adults, in contrast to many previous reports that have emphasized how common this tumor is in children. Eight patients presented with proptosis and without prior diagnosis of lymphoma, and 5 patients developed orbital deposits in the course of a known systemic lymphoma. Of the 8 patients whose orbital biopsies established the diagnosis, 4 were found concomitantly to have other sites of disease, and 4 patients developed other evidence of lymphoma from 2 to 15 months after orbital biopsy. None of the cases in this series was interpreted as a primary orbital lymphoma. The histopathologic findings, the problem of histogenesis, and the need for systemic staging of cytologically malignant orbital lymphoma are discussed.