The unusual suspect: Inverted follicular keratosis of eyelid simulating a malignant lesion

An elderly gentleman presented with a progressively growing eyelid mass accompanied by one episode of blood-tinged discharge. Examination revealed a hyperpigmented, pedunculated mass [Fig. 1a]. An excision biopsy [Fig. 1b] was performed, and histopathology revealed an endophytic growth of squamous epithelium with characteristic squamous eddies [Fig. 1c and 1d], suggestive of inverted follicular keratosis (IFK). It is often misdiagnosed as malignant due to its predilection for the elderly and its rapid growth.[1,2] Desquamation of the hyperkeratotic epithelium may cause bleeding from the lesion.[3] Differential diagnoses include warts, pyogenic granuloma, seborrheic keratosis, keratoacanthoma, basal cell carcinoma, melanoma, and squamous cell carcinoma.[2] Management includes topical imiquimod and/or surgical excision.Figure 1: (a) Clinical image of the patient showing a pigmented mass on the right upper eyelid (b) Gross appearance of the excised specimen (c) Photomicrograph demonstrating endophytic lobules (arrow) and squamous eddies (star). Hematoxylin and eosin, 4×. (d) Photomicrograph showing squamous eddies (arrow). Hematoxylin and eosin, 10×Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.