Deceptive appearance of primary mucinous carcinoma of the eyelid: A rare case and literature review.

Primary mucinous carcinoma (PMC) of the eyelid is an exceedingly rare malignancy that often presents as an innocuous, slow-growing lesion, leading to frequent misdiagnosis as a benign entity. This diagnostic challenge can lead to delayed treatment and potential recurrence. We report a unique case of PMC in a patient who presented with a clinically benign-appearing lesion, initially considered for differential diagnoses such as keratoacanthoma, epidermoid cyst, and pilomatrixoma. A diagnostic surprise emerged when histopathological evaluation confirmed PMC. Despite recommendations for wide local excision, the patient opted for observation due to concerns about postoperative morbidity. Over a two-year follow-up period, no recurrence was noted. This case highlights the deceptive presentation of PMC, the importance of histopathological confirmation, and the role of individualized patient management. A review of the literature further underscores the rarity of this entity and the necessity for long-term surveillance.