Diffuse large B-cell lymphoma of the orbit: clinicopathologic, immunohistochemical, and prognostic features of 20 cases.

PURPOSE: To evaluate a series of orbital diffuse large B-cell lymphomas (DLBCL) for prognostic features and therapeutic outcomes. DESIGN: Retrospective multicenter case study of clinical and immunohistochemical features of 20 patients. METHODS: Clinical, histopathologic, and immunohistochemical features were correlated with outcomes. Immunohistochemistry for biomarkers including Bcl-6, CD5, CD10, CD20, FOXP1, GCET1, and MUM1 was performed to differentiate between 2 major genetic subtypes of DLBCL: activated B-cell-like (ABC) and germinal center B-cell-like (GCB). RESULTS: Sixteen patients presented with unilateral and 4 with bilateral tumors. Three had bony erosion of the orbit on imaging studies. Of 14 patients with detailed follow-ups, 3 had a prior or concurrent lymphomatous disease; 8 had stage I disease (limited to the orbit) at presentation; and 3 were newly diagnosed with systemic (stage IV) DLBCL. Localized disease was treated with combined systemic chemotherapy, including rituximab and radiation with no deaths to date; there was 1 death related to systemic DLBCL. Clinical staging was the best predictive method and no immunohistochemical feature or subcategory (ABC vs GCB) correlated with outcome. CONCLUSIONS: Primary orbital DLBCL has a more favorable prognosis than systemic DLBCL and may arise from a preexistent hematolymphomatous neoplasm (4 out of 20 cases). In our series, orbital DLBCL had a 57% likelihood of being restricted to the ocular adnexa. Clinical staging was more helpful in predicting outcome than any single immunohistopathologic feature or combination of biomarkers. Orbital radiation of 30 gray in conjunction with systemic chemotherapy with rituximab can achieve disease-specific survival approaching 100% in purely localized cases.