Subungual Basal Cell Carcinoma: A Rare Nail Tumor with a Challenging Diagnosis.

Subungual basal cell carcinoma (BCC) is a rare disorder associated with many factors, including contact with some topical and oral substances. A differential diagnosis and an early approach are important to minimize the functional damage of the limbs affected by this type of tumor. We report a case of subungual BCC in a 70-year-old woman that was managed by surgical excision. The patient's medical history included the previous use of arsenic. We emphasize the contribution of an early diagnosis to achieve better treatment results in this instance.