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)