Newer variants and simulants of basal cell carcinoma

Basal cell carcinoma (BCC) has characteristic clinical and histopathologic findings that facilitate accurate diagnosis. There are, however, many variants and simulants of BCC that may cause clinical and/or histopathologic confusion. These entities often have features in common with BCC, with nodular or sclerosing basaloid islands, peripheral palisading, stromal retraction, (pseudo)-glandular formation, and/or prominent mucin. Recently described BCC variants, including signet-ring BCC and granular cell BCC, are discussed. Less commonly appreciated basaloid simulants, including ameloblastoma, cloacogenic carcinoma, and mucinous carcinoma, are described. Distinguishing among these variants and simulants of BCC is important because treatment and prognosis of each may vary.