Metastatic basal cell carcinoma: a review of six cases

Basal cell carcinomas (BCCs) are locally invasive skin neoplasms of cells in the epidermal basal layer. BCC metastasis remains a rare phenomenon, although such an event is associated with high morbidity and mortality. It has been suggested that certain features may be used to predict metastatic spread, including histological subtype, size, and perineural or lymphovascular invasion. We reviewed cases of metastatic BCC seen at Royal North Shore Hospital over a 16 year period. Pathology reports and specimens of both the primaries and metastatic lesions were obtained, and reviewed by an independent pathologist for second opinion on histopathology and confirmation of metastatic BCC. Six cases were found and reviewed (age 60±12, 17% F). Three of the six cases involved primaries located in the head and neck. The most common primary histological subtypes were morpheaform & infiltrative. This was accompanied by perineural and/or lymphovascular invasion in two cases. Three of the cases demonstrated large primaries of greater than 50 mm in diameter. One was found to have squamous differentiation in both the primaries and metastases. The most common site of metastases was the lungs, occurring in three of the cases, whilst other metastatic locations included bone and lymph nodes. We propose that primary BCCs with suspicious clinical/histopathological features be monitored closely, especially those from the head and neck region. We also propose further consideration of immunohistochemical markers as potential metastatic predictors.