Chromosomal imbalances in lymphoid tumors of the orbit.

PURPOSE To identify chromosomal gains and losses in lymphoid tumors of the orbit and to examine whether such abnormalities are related to orbital presentation, disease severity, or risk for recurrent disease. METHODS Biopsy specimens from 26 patients were examined by histomorphologic and immunohistochemical analysis. Lymphomas were classified according to the Revised European-American Lymphoma Classification. Chromosomal imbalances were detected by high-resolution comparative genomic hybridization (CGH). Clinical data were obtained by retrospective evaluation of medical records. RESULTS Chromosomal imbalances were detected in 0 of 6 patients with idiopathic orbital inflammation, 0 of 2 with benign reactive lymphoid hyperplasia, 3 of 3 with highly malignant diffuse large B-cell lymphoma, 4 of 10 with marginal zone B-cell lymphoma, 0 of 1 with chronic lymphatic leukemia lymphoma, and 1 of 4 with immunocytoma. Among the low-grade malignancies, chromosomal imbalances were seen in 1 of 9 at stage IAE, 2 of 3 at stage IIE, and 2 of 3 at stage IVE. Chromosomal imbalances were observed in all primary tumors from the five patients that later developed recurrent disease. In 14 of 23 imbalances with intrachromosomal breaks outside the centromere region, the breaks were present at bands with known fragile sites. No chromosomal imbalances specific for orbital presentation were detected. CONCLUSIONS Chromosomal imbalances were seen mainly in orbital lymphomas that were either highly malignant or at an advanced stage. CGH analysis of orbital lymphomas could be prognostically relevant, but further studies are required to confirm this notion.