Basal-cell carcinoma: cytologic and immunocytochemical findings in fine-needle aspirates.

The smears of fine-needle aspirates corresponding to 137 histologically proven basal-cell carcinomas (BCCs) were reviewed. Satisfactory for evaluation were 127 smears; the remaining 10 were unsatisfactory. In 124 cases (97.6%), the cytologic diagnoses coincided with the histologic ones. The remaining 3 were false negatives, and the subsequent histologic correlation demonstrated superficial BCC missed by the needle. The cytologic criteria that permitted a diagnosis of BCC were: variable-sized and irregular-shaped cohesive epithelial clusters, round to oval monomorphic nuclei, bland chromatin pattern, and sparse cytoplasm. In 35 cases, a panel of antibodies was used in the smears and in the respective histologic sections. Epithelial clusters of BCC showed an intense and diffuse positivity for AE-3 and BerEP4, while UEAI and AE-1 were negative. Although HMB45 and S100-A tested negative in the epithelial clusters, a faint and sparse focal positivity for HMB45 and S-100A was seen in some clusters. This positivity is believed to correspond to just a few normal melanocytes and Langerhans cells trapped in the neoplastic epithelial clusters. In the histologic correlates, the same results were obtained, although HMB45 positivity was more conspicuous at the periphery of the neoplastic nests.