Background/aims Fine needle aspiration biopsy has become a standard technique to obtain material from primary uveal melanoma for diagnosis, prognostication and research. Cytopathology requires a significantly greater tissue yield for a positive diagnosis compared to other molecular tests. The purpose of this report was to compare sample retrieval for cytopathology between trans-scleral and vitrectomy-assisted transvitreal biopsy in the same tumour in patients who underwent iodine-125 brachytherapy.

Methods All clinical records of patients who underwent iodine-125 brachytherapy for the treatment of uveal melanoma in conjunction with pars plana vitrectomy from whom trans-scleral and vitrectomy-assisted transvitreal fine needle biopsies were obtained, were reviewed. Baseline patient and tumour characteristics, biopsy sample yield for cytopathology, and surgical outcomes were reviewed.

Results Thirty-eight patients with a median follow-up time of 2 months were included. Overall, 27 of 38 (71%) of transvitreal biopsies, and 25 of 38 (66%) of trans-scleral biopsies yielded sufficient material for cytopathologic analysis (p=0.62). For transvitreal and trans-scleral biopsies, larger tumours were associated with significantly higher cytopathologic yield, but tumour location did not significantly affect cytopathologic yield.

Conclusions Trans-scleral and vitrectomy-assisted transvitreal fine needle aspiration biopsy resulted in similar tissue yield for cytopathologic analysis. As molecular prognostication becomes the standard of care for obtaining patient information and directing clinical management, further investigation of biopsy techniques is warranted.