Figure 2

Immunohistochemical findings of basal cell neoplasm and adenoid cystic carcinoma. A & B. Immunostaining of basal cell neoplasms for CK7 (A) and p63 (B) illustrate the pattern of epithelial-myoepithelial differentiation, especially in tubular or trabecular type tumors. C. CK5/6 immunostaining reveals that most basal cell adenocarcinomas exhibit diffuse cytoplasmic staining, which differs from the staining pattern in adenoid cystic carcinoma. D. Nuclear β-catenin expression in a basal cell adenocarcinoma. E. Unlike basal cell adenocarcinomas, which are negative for S100P protein, most adenoid cystic carcinomas show nuclear expression of S100P protein. F. Unlike adenoid cystic carcinoma, which is diffusely and strongly positive for CD117, basal cell adenocarcinoma shows focally and weakly to moderately positive CD117 staining.