Incidental detection of rare metastatic basal cell carcinoma on screening mammography.

Basal cell carcinoma (BCC) is the most common nonmelanoma skin cancer but rarely metastasizes, with an estimated metastatic rate of 0.1%. Metastatic spread to axillary lymph nodes is extremely uncommon, and to our knowledge, no prior cases have reported incidental detection on screening mammography. We report the case of a 48-year-old Caucasian female with a history of renal transplants, chronic immunosuppression, and multiple biopsy-confirmed BCCs and cutaneous squamous cell carcinomas who presented with a new axillary mass incidentally found on screening mammography. Final pathology following axillary lymph node dissection revealed metastatic BCC. This case illustrates the diagnostic complexity of axillary masses found on screening mammography and underscores the need for vigilant evaluation of BCC metastases in immunosuppressed patients. It highlights the diagnostic limitations of imaging and core biopsy in distinguishing BCC from cutaneous squamous cell carcinomas or metastatic breast carcinoma. Given the poor prognosis of metastatic BCC, this report supports more proactive imaging strategies in high-risk individuals and emphasizes the need for further research into optimal management.