Metastatic head and neck cutaneous basal cell carcinomas: a retrospective observational study

Cutaneous basal cell carcinoma is usually an indolent and slow-growing tumor with potential for local invasion and recurrence; however, metastatic events are exceedingly rare. The annual incidence of metastasis is estimated to range between 0.00281 and 0.05%. A retrospective search in the pathology database of a single tertiary institution was performed in the period between 1999 to 2019. Primary cutaneous metastatic basal cell carcinomas had paraffin blocks and glass slides retrieved. A total of 8673 cases was identified. The overall prevalence of metastatic tumors was 0.05% (4/8673). The median patient's age at diagnosis was 61 years old (range 52-79). The most common primary site of tumor was nose (2/4) and the most common histological subtype was infiltrative. The sampled lymph nodes were identified during primary tumor resection, except for 1 patient who had a sentinel lymph node biopsy performed as a surgeon individual decision. One patient had hematogenous spread to the pleura, diagnosed 5 years after diagnosis. In summary, this study adds new data to the current literature in metastatic primary cutaneous basal cell carcinomas and highlights the importance of early diagnosis and appropriate surgical excision in an effort to prevent local advanced disease, recurrence and lymphovascular dissemination.