Clear cell basal cell carcinoma with pulmonary metastasis: case report and literature review.

Clear cell basal cell carcinoma is a rare histological variant of basal cell carcinoma, which has been well described in the literature. We herein report a case of a 56-year-old man who developed lung metastasis from a rather aggressive tumor that grew very rapidly to involve the parotid gland, the mandibular bone, and even the petrous portion of the temporal bone, the middle ear, and the dura mater. Histological diagnosis was clear cell carcinoma, and initially a salivary origin was suspected. Only in the resection specimen, we found areas of more conventional basal cell carcinoma, and final diagnosis was clear cell basal cell carcinoma. We herein report a case of this rare variant and comment on the histopathological differential diagnosis and the possible relation between these tumors and Gorlin-Goltz syndrome.