Metastatic basal cell carcinoma: a clinicopathologic study of seventeen cases.

Basal cell carcinoma is a common cutaneous neoplasm that rarely metastasizes. We studied the clinical and pathologic features of 17 patients with metastatic basal cell carcinoma as recorded in the files of the Armed Forces Institute of Pathology (AFIP). Sixteen of the patients were male, and as far as it could be determined, all were white. The most frequent site of metastasis was lung (9 cases), followed by bone (5), lymph nodes (4), liver (3), spleen (1), and adrenal gland (1). Thirteen of the patients had metastatic lesions involving only one organ system. Mean survival time after metastasis was 1.6 years. Features of metatypical (basosquamous) basal cell carcinoma were common in the primary and recurrent tumors, and metastatic lesions generally had a metatypical or adenoid pattern. Two of the five bony metastases demonstrated shadow cells characteristic of pilomatrixoma. The metatypical pattern of a basal cell carcinoma is a feature of an aggressive lesion with the ability to metastasize.