Purpose: To report cytopathological observations on the cells retrieved from the 25-G cannula used during prognostic transvitreal fine-needle aspiration biopsy of choroidal melanoma.
Methods: Transvitreal fine-needle aspiration biopsy of choroidal melanoma was performed through a 25-G valved cannula. Twenty samples from 20 consecutive patients were obtained. Most tumors were treated with plaque radiation therapy (16/20, 80%) following standard clinical guidelines. Four enucleated globes (4/20, 20%) were subjected to a similar transvitreal biopsy before enucleation.
Results: Cytopathological analysis of the cells retrieved from the cannula revealed the absence of any cells in 4 of 20 samples (20%). In the remaining 16 samples, definite melanoma cells and atypical cells (probable melanoma cells) were observed in 2 samples each (total 4, 25%). Histiocytes (4/16, 25%) and lymphocytes (1/16, 6%) were also observed. Thirteen samples (13/16, 81%) contained conjunctival epithelial epithelium. Prognostication could be performed on all fine-needle aspiration biopsy samples (20, 100%).
Conclusion: Use of a 25-G valved cannula offers potential advantages by isolating the needle tract and by allowing retrieval of the contaminating cells without affecting the prognostic yield of the fine-needle aspiration biopsy sample.