Introduction: Adrenal pheochromocytomas have the same embryonic origin, i.e. the neural crest, as peripheral neuroblastic tumors such as ganglioneuromas, ganglioneuroblastomas and neuroblastomas. Ganglioneuromas are benign and silent tumors in that they usually do not secrete catecholamines in contrast to pheochromocytomas. Rarely, they can associate with pheochromocytomas to form composite tumors.
Patients and methods: We have retrospectively studied seven patients with pheochromocytoma/ganglioneuroma composite adrenal tumor followed up in two French academic departments of endocrinology. The clinical, biochemical, genetic and histological characteristics of the tumors were collected. In addition, immunohistochemical labelling of tumor slices with specific antibodies directed against the key enzyme for adrenaline synthesis phenylethanolamine N-methyltransferase (PNMT) were carried out in order to better individualize the two components of the neoplasms.
Results: In all cases, association of the adrenal mass with clinical and biological signs of catecholamine excess led to the initial diagnosis of pheochromocytoma followed by adrenal surgery. The ganglioneuroma components of the neoplasms were identified at pathological examination of the tissues. Four patients carried germinal mutations affecting the NF1 (two patients), KIF1Bbeta (one patient) and MYC-associated factor (MAX; one patient) genes. Five patients harboured associated neoplasias and two patients had subclinical hypercortisolism related to hyperplasia of the adrenal cortex adjacent to the tumors. Immunohistochemical PNMT labellings of tumor sections allowed perfect discrimination of the two tumor tissue components by revealing intense staining of pheochromocytes contrasting with no signal in ganglion cells.
Conclusion: We report a large series of adult adrenal pheochromocytoma/ganglioneuroma composite tumors. In addition, we show that, in addition to routine histological examination of the tumor tissues, immunohistochemical studies with antibodies to PNMT can be helpful for the diagnosis of the disease by facilitating identification of the two tumor components.
27 Apr - 01 May 2013
European Society of Endocrinology