A case report of squamous cell carcinoma mimicking interdigital intertrigo.

Squamous cell carcinoma (SCC), also known as epidermoid carcinoma, represents the most common malignant tumor affecting the nails. A 60-year-old tailor with no significant medical history presented with a three-year history of macerated skin between the toes, previously treated with a topical antifungal. Dermatological examination revealed a verrucous, infected ulceration with infiltrated and hyperkeratotic edges, characterized by a whitish, fissured base. This lesion in the fourth interdigital space and extended onto the dorsal surface of the foot without any other associated symptoms. The clinical diagnosis identified it as a neoplastic ulceration. An initial biopsy found keratoacanthoma but showed no malignant features. However, follow-up biopsy at our department revealed moderately differentiated SCC. Surgical resection was successful in treating our patient. Diagnostic errors due to insufficient understanding of the pathology and inadequate biopsy methods contribute to the progression of SCC. Surgery is the main treatment for such malignant tumors.