Abstract
Carcinoma cuniculatum is a variant of squamous cell carcinoma, characterized by a slow growth with progressive crypt-like invasion of deep tissue. This tumor is frequently misdiagnosed as a benign skin lesion both clinically and histopathologically. The final diagnosis is often delayed as it requires a large sample biopsy. We report the case of a 67-year-old patient who presented to us with a recurring chronic ulcer over a surgical scar of 5 years of evolution. Only after a wide resection of the chronic ulcer was it possible to achieve the correct diagnosis of this large and poorly evolving carcinoma. The subsequent reconstruction with a musculocutaneous gracilis free flap allowed the patient to walk again.