Composite pheochromocytoma or paraganglioma of adrenal gland: A case report with immunohistochemical studies and electron microscopic examination

Composite pheochromocytoma or paraganglioma of the adrenal gland is a well-recognized, yet extremely rare tumor with only one case reported in Korea. We report a case of incidentally found composite pheochromocytoma and ganglioneuroma of the adrenal gland in a 44-year-old female composed of intermingled components of pheochromocytom, ganglioneuroma, and cells with intermediate features. On immunohistochemical staining, the pheochromocytoma component was positive for synaptophysin and chromogranin, but negative for S-100 protein. Staining for the S-100 protein revealed sustentacular cells which formed a peripheral coat around the "Zellballen" and Schwann cells. The Fontana-Masson stain defined neuromelanin granules of ganglion cells and the ganglion cells expressed neural markers such as neurofilament proteins. Ultrastructural findings revealed pheochromocytes with a round or ovoid nucleus and occasionally prominent nucleolus containing numerous adrenaline and noradrenaline granules.