Subclinical dissemination in basal cell carcinoma: A case of 19-year latency to pulmonary metastasis

Basal cell carcinoma (BCC) is the most common skin malignancy in humans; however, metastases are exceedingly rare. We report a case of scalp basal cell carcinoma (BCC) in a 48-year-old female, initially excised in 2004. Local recurrence in 2007 was further excised; focal superficial margin involvement was managed conservatively, given low-risk features. In 2014, regional cervical metastasis was identified with no evidence of active scalp disease and completely excised in 2015. Despite this, bilateral pulmonary metastases were detected in 2023. Immunophenotypic continuity was confirmed across all sites, with no squamous differentiation. Perineural invasion and intramuscular emboli were detected without demonstrable lymph node involvement (0/11). This case meets Lattes and Kessler’s criteria for metastatic BCC, exhibiting an unusually long latency of 19 years from initial diagnosis. It underscores the importance of clinical vigilance in typically indolent neoplasms and contributes to the limited literature on subclinical disease and disease trajectory.