Metatypical Basal Cell Carcinoma: Report of A Case with Granular Cell Change

Granular cell Basal cell carcinoma (BCC) is an extremely rare variant of BCC which was first reported in 1979. Granular cell BCC is characterized by large cells with abundant eosinophilic and granular cytoplasm and eccentrically located nucleus. Metatypical BCC is another rare variant of BCC, composed of nests and cords of cells, with moderate squamous maturation. A 43 y/o woman presented with an ulcerated lesion of upper lip. The lesion underwent surgical excisional biopsy. Microscopic examination revealed skin tissue heavily infiltrated by basaloid tumor cells, arranged in nests with peripheral palisading and cleft formation, consistent with basal cell carcinoma, as well as focal squamous differentiation and granular cell change. Tumor cells expressed Ber-EP4 and CK5,6, but showed negative reaction for S100 on immunohistochemical study. Tumor cells with granular cell change also expressed CD68. This subtype of BCC is rare and granular cell change can also occur in other neoplasms. Definite diagnosis would be difficult if no relationship is seen between tumor cells and surface epidermis or prepared sections do not contain conventional BCC, so pathologists ought to be familiar with this subtype of BCC for appropriate diagnosis.