Correlation of impression cytology with histopathology in the diagnosis of ocular surface squamous neoplasia

Abstract

Background: Ocular surface squamous neoplasia (OSSN) includes a wide spectrum of conjunctival and corneal intraepithelial neoplasia which can manifest as dysplasia, carcinoma in situ, and invasive squamous cell carcinoma. OSSN can be diagnosed by certain noninvasive techniques as well as invasive histopathological examination. One of such noninvasive techniques is impression cytology which refers to the histological study of superficial layers of ocular surface epithelium. Aim: The aim of this study was to assess the accuracy of impression cytology in the diagnosis of OSSN using cellulose acetate paper by correlating with histopathology. Materials and Methods: This is a prospective observational and interventional study conducted at a tertiary referral center in Chennai. This study was conducted from January 2016 to July 2017 and included 43 eyes of 42 patients presenting with conjunctival mass at the limbus or over the conjunctiva. Hospital ethics committee approval was obtained. Results: A total of 43 excision biopsies of 42 patients suspected for OSSN were performed. There was correlation in 36 eyes (83.72%), and in 7 eyes, there was no correlation (16.27%). The cases having hyperkeratotic lesions were missed by the impression cytology. Conclusion: Impression cytology can be used as a screening tool in the diagnosis of OSSN and in the follow-up of patients with recurrence. However, histopathology always remains the gold standard in diagnosing OSSN.