Diagnostic transvitreal fine-needle aspiration biopsy of small melanocytic choroidal tumors in nevus versus melanoma category.

PURPOSE To report an experience with fine-needle aspiration biopsy of selected small melanocytic choroidal tumors during the interval from April 13, 1983, through January 19, 2001. METHODS Retrospective descriptive case series report of 34 patients with a small melanocytic choroidal tumor (maximal diameter, < or = 10 mm; thickness, > or = 1.5 mm but < or = 3 mm) evaluated diagnostically by transvitreal fine-needle aspiration biopsy prior to treatment. None of the tumors had invasive features at the time of biopsy. RESULTS Patients ranged in age from 26 to 73 years (mean, 50.9 years). The evaluated choroidal tumors had a mean maximal basal diameter of 8.0 mm and a mean maximal thickness of 2.4 mm. Eighteen of the 34 tumors (52.9%) had been documented to enlarge prior to biopsy. Biopsy was performed in all cases using a 25-gauge hollow lumen needle and a transvitreal approach via a pars plana puncture site. The biopsy yielded a sufficient aspirate for cytodiagnosis in 22 of 34 cases (64.7%). In these cases, the tumor was classified as malignant melanoma in 16 (47.1% of total), intermediate lesion in 4 (11.8%), and benign nevus in 2 (5.9%). The 12 tumors that yielded an insufficient aspirate and the four lesions that yielded intermediate cells continued to be classified as "nevus versus melanoma" and were monitored periodically for growth or other changes. Four of the 12 tumors that yielded an insufficient aspirate for cytodiagnosis and all four lesions that yielded intermediate cells were eventually reclassified as small choroidal melanomas and treated. The remaining eight tumors that yielded an insufficient aspirate and the two tumors that yielded benign nevus cells were classified as benign nevi at the most recent follow-up evaluation. CONCLUSIONS Fine-needle aspiration biopsy showed that a substantial proportion of small melanocytic choroidal tumors likely to be classified clinically as small choroidal melanomas in many centers were in fact benign nevi or intermediate lesions.