[Basal cell and basosquamous carcinomas of the external ear. Immunohistochemical study]

Malignant neoplasms of the external ear are difficult diseases of the cervical-facial area to study clinically and therapeutically. The most frequent malignant histological patterns are spinocellular and basocellular carcinomas. Melanomas, basosquamous or "metatypical" carcinomas are less frequent. The latter have a transition histological pattern halfway between a basocellular and spinocellular carcinoma. In our experience, some external ear neoplasms, diagnosed as basocellular, were clinically more invasive (aggressive). Therefore we studied the immunohistochemistry of operative specimens with monoclonal antibodies (MoAb) with the purpose of revaluating the diagnosis after follow-up, and of detecting unrecognized basosquamous carcinomas. We studied 4 patients (2 male and 2 female) aged between 58 and 78, examined in the period 1990-92 an a diagnosed as having an external ear basocellular carcinoma. The immunohistochemical study was carried out using anti-CEA (carcinoembryonal antigen) monoclonal antibodies, high molecular weight acid anticytokeratins (anti-AE3) and low molecular weight basic anticytokeratins (anti-AE1). Appendage origin of the neoplasms was excluded after carrying out MoAb anti-CEA tests, negative in all patients. Epithelial origin of the neoplasms were confirmed after carrying out MoAb anti-AE3 tests, positive in all patients. After carrying out MoAb anti-AE1 tests, positive in 3 patients out of 4, we reviewed the classification of 2 basocellular carcinomas out of 4. These tumors evidenced an atypical dyskeratosis and a positivity for intracellular keratinization. These aspects were not evidenced in the previous histological examinations using routine stains and could be an index of unfavourable clinical evolution of these two cases from a basocellular carcinoma toward a more aggressive basosquamous carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)