Basosquamous cell carcinoma in congenital nevus: case study in a young patient

Basosquamous cell carcinoma is a relatively rare skin neoplasm that combines characteristics of both basal cell and squamous cell carcinoma. It is currently recognized as a subtype of basal cell carcinoma with a much more aggressive behavior. Its clinical presentation is nonspecific, and its diagnosis is generally made only after a biopsy. It predominates in male patients during the seventh decade of life and tends to appear in photo-exposed regions. We present a 32-year-old male patient with no significant medical history who presented to the dermatology clinic with a mole on his left thigh since birth, which had been growing over the previous 12 months. The biopsy was compatible with typical metastatic basal cell carcinoma. Our patient's case shows an atypical presentation due to its location and its onset 40 years earlier than the average age reported in the literature.