Epidermal Choristoma of the Tongue: A Potential Diagnostic Pitfall

We report a rare case of epidermal choristoma of the tongue in a 52-year-old female, presenting as an asymptomatic brown-to-black macule clinically resembling a melanotic macule. Excisional biopsy revealed abrupt transition from oral mucosal epithelium to epidermis-like stratified squamous epithelium with hyperkeratosis, hypergranulosis, basal cell melanosis, and mild melanocytic hyperplasia, along with sebaceous adnexal structures in the lamina propria, confirming the diagnosis. Epidermal choristoma is an exceptionally rare developmental lesion of ectodermal origin, with nine oral cases reported to date. Due to its nonspecific clinical appearance, it may be mistaken for benign melanotic lesions or early mucosal melanoma. Complete surgical excision is curative, with no recurrence observed at 15-month follow-up in this case. This report highlights the importance of histopathologic evaluation of pigmented tongue lesions to avoid misdiagnosis and ensure appropriate management.