Impression Cytology in a Series of Clinically Diagnosed Ocular Surface Melanocytic Lesions

PURPOSE To report impression cytology (IC) results of clinically diagnosed ocular surface melanocytic lesions. METHODS Ten patients with a clinical diagnosis of an ocular surface melanocytic lesion underwent IC using cellulose acetate strips and Periodic acid Schiff-Papanicolaou staining. Excisional biopsy of lesions was performed in case of observing atypical cells on IC or at the patient's request, and excised specimens were subjected to histopathological analysis. Agreement between clinical diagnoses and IC results and between IC results and histopathology were evaluated. RESULTS Clinical diagnoses were nevi in 6, primary acquired melanosis (PAM) with atypia/melanoma in 2, and atypical nevus versus pigmented conjunctival intraepithelial neoplasia (CIN) in 2 cases. IC results were suggestive of a benign nevus in 7, PAM with atypia/melanoma in 2 and CIN versus an atypical epithelioid type melanocytic lesion in 1 case. IC results were consistent with the clinical diagnoses in 9 cases (Cohen's kappa index of 0.83) and excluded CIN in 1. Histopathology in 6 cases disclosed benign melanonevus in 3, malignant melanoma in the context of PAM with atypia in 2, and CIN in 1 case. Histologic results were well correlated with the IC features (Cohen's kappa index of 0.74). CONCLUSION By demonstrating typical cytomorphological features of ocular superficial layers IC diagnosed the true nature of melanocytic ocular surface lesions in the majority of cases. Although IC does not substitute histopathology, given the high correlation between IC results and histopathology, it can be of great assistance in diagnosis and management of ocular surface melanocytic lesions.