Neuroendocrine differentiation of a metastatic basal cell carcinoma in a patient with basal cell nevus syndrome

A 48 year-old white male with basal cell nevus syndrome presented with a me tastatic basal cell carcinoma with neuroendocrine features. The tumor manif ested aggressive behavior, having deep local invasion and metastases to par a-aortic lymph nodes and bone. Neuroendocrine differentiation has rarely be en associated Midi basal cell carcinoma. The histologic, immunohistochemica l, and electron microscopic studies of this rare tumor are described.