Clear-cell, basal cell carcinoma: histopathological, histochemical, and electron microscopic findings.

Another histological variant of basal cell carcinoma (BCC) is described. This clear-cell variant appeared as a recurrent lesion on the back of an elderly man. Histological examination revealed that part of the tumor was composed of clear cells with faintly eosinophilic cytoplasm. Degenerative changes were present, along with calcium deposition. Mucin was present within the stroma and within the degenerative areas of the tumor. Staining with anti-S-100, anti-keratin, and anti-carcinoembryonic antigen antibodies was negative. Electron microscopy demonstrated epithelium-derived cells with marked phagolysosomal accumulation within the cytoplasm. We conclude that this clear-cell variant is due to degenerative change within a BCC.