Aggressive Basal Cell Carcinoma With Rib Metastasis: An Uncommon Presentation of a Common Skin Cancer.

Basal cell carcinoma (BCC) is the most common skin cancer, generally characterized by slow growth and minimal risk of metastasis. However, in rare cases, particularly those left untreated for extended periods, BCC can become deeply invasive and even metastatic. We report the case of a 72-year-old woman with a long-neglected ulcerating facial tumor that was ultimately diagnosed as BCC with extensive local invasion and biopsy-proven metastasis to the left anterior fifth rib. Imaging revealed destruction of the maxilla, orbit, and palate. The patient was managed with a multimodal approach, including hedgehog pathway inhibition with vismodegib, immune checkpoint blockade with cemiplimab, palliative radiation therapy, and ultimately extensive surgical resection. The coordinated therapeutic response led to clinical improvement and disease stabilization. This case underscores the potential aggressiveness of neglected BCC and reinforces the value of early detection and comprehensive, multidisciplinary management in advanced presentations.