Neuroendocrine features of adrenal pheochromocytomas: histological and immunocytochemical evaluation

Neuroendocrine features of 30 surgically removed adrenal pheochromocytomas were evaluated combining conventional histochemistry and immunocytology. The reactivity for neuron-specific enolase (NSE), S-100 protein, vasoactive intestinal peptide (VIP), calcitonin and ACTH was tested according to the peroxidase anti-peroxidase (PAP) method using polyclonal antibodies. The neuroendocrine marker NSE was found in all cases. S-100 protein was present in satellite cells in 11 (36.6%) tumors. Rare immunoreactive cells for somatostatin were found in 16 (53.3%), for VIP in 8 (26.6%), for calcitonin in 7 (23%), and for ACTH in 3 (10%) cases. Our results proved the histological and functional heterogeneity of pheochromocytomas. The multiple synthetic activity is their inherent feature as in other neuroendocrine tumors.