Of note, the hypercellular appearance and the lack of loosely populated Antoni B areas and classic Verocay bodies led to extensive immunohistochemical analyses of these three cases, and a number of markers were assayed in order to rule out neurofibroma (CD34), leiomyosarcoma (desmin), angiosarcoma (CD34 and ERG), metastatic GIST (c-kit, DOG1), malignant melanoma (Melan A), pheochromocytoma (chromogranin A) as well as adrenal cortical tumors (SF1, Alpha-inhibin). The gene discussed is ERG; the disease is hereditary pheochromocytoma-paraganglioma.