Uveal melanoma is highly aggressive, and overall prognosis depends on mutation status. Fine-needle aspiration biopsies (FNABs) play an important role in obtaining fresh tissue for cytologic diagnosis and molecular studies. It has been suggested that, although FNAB usually provides high diagnostic accuracy, there may be limited cellularity, which may compromise diagnostic potential for molecular studies. FNABs of uveal melanocytic lesions were evaluated to assess sample adequacy for both cytologic evaluation and next-generation sequencing (NGS).
The authors retrospectively evaluated 36 cases of melanocytic uveal lesions from 2015 to 2018. Samples were obtained by ophthalmologist-performed FNAB and aliquoted for cytology and NGS. Various combinations of direct smears, liquid-based cytology slides, cell blocks, and immunohistochemical stains for melanocytic markers were performed. All samples were tested for molecular alterations using hybrid-capture-based NGS.
There was sufficient material for cytologic diagnosis in 33 of 36 cases (92%), for NGS testing in 30 of 36 cases (83%), and for both cytologic diagnosis and NGS testing in 28 of 36 cases (78%). Of 7 cases that were cytologically categorized as indeterminate or diagnosed as "atypical" or "nondiagnostic," NGS testing was sufficient and diagnostic for melanoma in 5 cases. Of the cases diagnosed as melanoma on pathology, 20 cases (87%) had concordant NGS testing results, 2 lacked molecular alterations, and 1 was insufficient for testing.
FNA sampling of melanocytic uveal lesions is adequate for both cytologic diagnosis and NGS testing. In a subset of cases in which pathologic findings were indeterminate, NGS testing results were clarifying for diagnosis. In addition, specific molecular alterations identified can aid in evaluating prognosis and guide further management.