Track: Case Reports

Abstract:

Basal cell carcinoma (BCC) is the most common skin cancer, with metastasis occurring in only 0.0028–0.55% of cases. Metastatic BCC (mBCC) carries a poor prognosis, and rare sites of spread include visceral organs, peritoneum, and spinal column. Aggressive histologic subtypes and large size increase metastatic risk. A man in his late 50s with chronic occupational sun exposure presented with ulcerating right temple (7 × 5 cm) and left neck (10 × 5 cm) nodular BCCs. Surgery was initially deferred; vismodegib therapy induced partial response, but discontinuation led to rapid progression with muscle, nerve, and soft tissue invasion. Resection revealed a morpheaform subtype, distinct from the original histology. Molecular profiling showed a tumor mutation burden of 84.55 mut/Mb with mutations in TP53, FGFR2, ARID1A, PTCH1, and SMO. After 32 months of stable disease, he was represented with bowel obstruction; pathology confirmed metastatic BCC in the bowel. Subsequent imaging revealed diffuse spinal, hepatic, pulmonary metastases, and peritoneal carcinomatosis. Despite spinal radiation and pembrolizumab (high tumor PD-L1 expression), disease progressed, culminating in transition to hospice. This case illustrates an exceptionally aggressive mBCC with rare metastatic sites. The coexistence of high tumor mutation burden, ARID1A mutation, and FGFR2 amplification suggests alternative pathogenic pathways beyond Hedgehog signaling, potentially informing targeted therapeutic strategies. Dermatopathologic recognition of aggressive histologic subtypes, coupled with early molecular profiling, may aid prognostication and guide management in high-risk BCC.

Menu

Rishabh Lohray