We present the case of an 82-year-old Caucasian woman with hypertension and diabetes but no other relevant personal or family history, who developed a large breast nodule. It was initially confused, both in imaging tests and in breast biopsy, with an invasive breast carcinoma. However, after its surgical excision, the definitive diagnosis was squamous cell carcinoma of cutaneous origin. At the time of diagnosis, it was a locally advanced cancer that continued with a local and distant aggressive behaviour, causing the death of the woman 16 months after diagnosis. It is an extremely rare case of cutaneous squamous cell carcinoma due to its aggressiveness and location, mimicking breast cancer.