Clear cell basal cell carcinoma.

We describe a case of clear cell basal cell carcinoma of the superficial type, presenting as a crusted eruption on the abdomen. Histological examination showed a solid proliferation of clear cells attached to the under-surface of an atrophied epidermis. In addition, distinct pagetoid infiltration was seen within the overlying epidermis. A focal connection between the clear cell portion and a deeper lying nodular basal cell carcinoma was demonstrated, elucidating the true nature of the lesion. Immunohistochemical studies and electronmicroscopy confirmed the epithelial derivation of the tumour. The clear cell appearance was due to multiple cytoplasmic electronlucent vacuoles which were not surrounded by membranes.