Adrenal and retroperitoneal mixed neuroendocrine-neural tumors

Four cases of mixed neuroendocrine-neural tumors composed of pheochromocytoma and neuroblastoma elements (including ganglioneuroma and ganglioneuroblastoma) were studied for the presence of catecholamine-synthesizing enzymes, neuroendocrine markers, and peptide hormones with clinicopathological correlations. Paroxysmal hypertension with hypercatech olaminemia was observed in 3 patients. One patient had an extremely elevated level of dopamine. The location of the tumor was in the adrenal glands in 2 patients and in the retroperitoneum in the other 2. Numerous electron-dense granules in the cytoplasm and neural processes with abundant neurotubules were characteristic of mixed neuroendocrine-neural tumors. Immunohistochemical study revealed that catecholamine-synthesizing enzymes were present in both components of the pheochromocytoma and neuroblastoma group, but phenylethanolamine N-methyltransferase was detectable only in epinephrine-producing tumors. Chromogranin and neurofilament immunoreactivities were present in both components; however, the intensity of chromogranin immunoreactivity was stronger in pheochromocytoma than in the other components. In contrast, neurofilament positivity was stronger in the neuroblastoma group than it was in pheochromocytoma. Multiple peptide hormones were immunoreactive in both components. Neuropeptide Y and met-enkephalin-positive cells were numerous in both; cells containing vasoactive intestinal peptide and somatostatin were less common but were comparatively more frequently found in ganglion cells than in pheochromocytoma cells.