Cushing syndrome-associated pheochromocytoma and adrenal carcinoma. An immunohistological investigation

Abstract

Seven adrenal carcinomas and seventeen pheochromocytomas (PHs), two of which were clinically associated with a Cushing's syndrome and one associated with multiple endocrine neoplasia Type II (MEN-II), were investigated immunohistologically with a panel of antibodies against intermediate filament proteins, a proliferation-associated nuclear antigen (Ki-67), neuroendocrine tumor markers, and different hormones on paraffin-embedded tissue sections and, from 19 cases, also on frozen tissue sections. Synaptophysin proved to be the most reliable tumor cell marker on both snap-frozen and paraffin-embedded tissue but, like antibodies against NSE, yielded unspecific stainings in the carcinomas. The two Cushing-associated pheochromocytomas (CaPH) showed the same immunohistological profile as the other PHs, except one chromogranin-negative tumor. Five PHs showed weak reactivity for calcitonin, one for serotonin, and two for a-HCG in small amounts. All PHs lacked other hormone expression, including ACTH. The average growth fraction was small (2.2%) in 13 cases, but 80% of the tumor cells were proliferating in one case of CaPH. Adrenal carcinomas showed only weak or no expression of keratin in one case, a homogenous or droplet, non-filamentous cytoplasmic staining with antibodies against neurofilament in frozen tissue section, and they were completely chromogranin-negative. The average growth fraction was 7.6% in 5 cases.