Fine-needle aspiration cytology and immunocytochemistry of orbital masses.

A series of 85 fine-needle aspiration (FNA) biopsies from orbital space occupying lesions of 82 patients are reviewed. A total of 32 benign lesions and 49 malignant lesions were conclusively diagnosed. In two cases the aspirates were insufficient for diagnosis. Of two cases, which were cytologically suspicious for lymphoma, a repeat FNA resulted in a conclusive diagnosis of lymphoma in one case, while the second case proved to be a pseudotumor on an open biopsy material. Of the 32 benign lesions seven were fibrosis, six pseudotumors, four epidermal cysts, four meningiomas, and three pleomorphic adenomas. The remaining cases included two hematomas, one granuloma, three inflammations, and one malformation. In 43 of 49 malignant tumors cytomorphology was corroborated with immunocytochemistry. Thirty five of these were low- or high-grade lymphomas, nine metastases, two sarcomas, two plasmacytomas, and one chloroma. All lymphomas were of B phenotype with monoclonal light chain expression. The rate of cell proliferation as measured by Ki-67 immunostaining varied between 4-25% and 30-80% for low- and high-grade lymphomas, respectively. These results confirm previous reports on the usefulness of FNA biopsy in diagnosing orbital masses and emphasize the value of immunocytochemistry in tumor characterization.