Importance of early diagnosis of periocular sebaceous carcinoma.

OBJECTIVE: To characterize the clinical, histopathological, and immunohistochemical features of periocular sebaceous carcinoma (SC) and identify diagnostic and prognostic indicators associated with poor outcomes. DESIGN: Retrospective case series. PARTICIPANTS: Sixty-two patients with 72 periocular SC tumours between 1994 and 2023 at the McGill University Health Centre. METHODS: Clinical presentation, histopathological features, and immunohistochemical profiles were reviewed to identify clinicopathological features associated with prognosis and outcome. RESULTS: The mean patient age was 73 years, with near-equal sex distribution. With similar frequency, SC occurred in the upper (n = 20) and lower eyelids (n = 19). Clinical misdiagnosis was common, most frequently as chalazion or basal cell carcinoma. Histologically, 58% of tumours were poorly differentiated, and pagetoid spread was observed in 32.5% of cases, which was strongly associated with orbital exenteration. Adipophilin had a positivity of 100% in tested cases, confirming its diagnostic reliability in immunohistochemistry, whereas other markers aided in distinguishing SC from other eyelid carcinomas. CONCLUSIONS: Periocular SC remains a highly aggressive and frequently misdiagnosed malignancy. Early biopsy of atypical eyelid lesions is critical to avoid diagnostic delay. Adipophilin serves as a robust diagnostic marker, and pagetoid spread represents a key prognostic indicator. These findings underscore the importance of heightened clinical vigilance and standardised histopathological evaluation to improve patient outcomes.