Cutaneous Squamous Cell Carcinoma as a Metastasis From Invasive Breast Cancer: A Case Report.

Cutaneous squamous cell carcinoma (cSCC) is a non-melanoma (keratinocyte) skin cancer. cSCC can occur as primary cSCC, second primary cancer (SPC), or metastasis. Histopathology and genetic or molecular studies are used to differentiate SPC from metastasis. Cutaneous metastasis (CM) is often misdiagnosed as a benign skin lesion. However, with early diagnosis and timely treatment, CM from breast cancer carries a good prognosis. Although surgery is the first-line treatment for cSCC, metastatic lesions respond well to chemotherapy and immunotherapy. Here, we present the case of a 73-year-old woman who presented to a dermatologist with a localized skin lesion. After detailed radiological and histopathological investigations, she was diagnosed with cSCC metastasis from breast cancer. With timely diagnosis, her CM responded well to chemotherapy.