Features and immunoexpression of p53, MIB-1 and proliferating cell nuclear antigen in adrenal neoplasms

Purpose: We evaluated the clinical features and immunoreactivity of p53 protein, MIB-1 antigen and proliferating cell nuclear antigen (PCNA) in adrenal neoplasms. Materials and Methods: A total of 26 patients with adrenocortical adenoma and 24 patients with carcinoma were treated with adrenalectomy. Clinical features and immunohistochemical reactions were compared in adult vs pediatric tumors. Results: There was a bimodal age distribution of carcinomas and adenomas, with a first peak occurring before age 5 years. The proportion of carcinomas in children (18 of 29) was higher than in adults (6 of 21). Carcinoma and adenoma occurring in children presented more commonly as the virilizing syndrome, while in adults Cushing's syndrome was more common. All adenomas in adults were p53 negative, while in children 4 of 11 adenomas (36%) were p53 positive. Histological Weiss criteria were the most reliable pathological features to distinguish adenoma from carcinoma. Other pathological features, including tumor weight, rate of mitotic figures and immunoexpression of p53 protein, MIB-1 antigen and PCNA, exhibited a striking difference in adenomas and carcinomas but none demonstrated sensitivity or specificity of 100%. Of all the computerized tomographic characteristics analyzed, including tumor size, shape, necrosis/hemorrhage, attenuation and contrast enhancement, only tumor size (greater than 5 cm) showed sensitivity and specificity of 100% in the differential diagnosis. Children and adults with carcinoma had similar curves of survival (p = 0.76). Carcinoma stage and PCNA immunoexpression displayed an association with outcome. Conclusions: Endocrine syndromes differed in adults and children but other clinical features were similar in both groups. The role of p53 protein, MIB-1 antigen and proliferating cell nuclear antigen in discrimination of adenomas from carcinomas is unclear.