Adrenocortical carcinoma (ACC) is a rare malignant tumour from the adrenal cortex. Half of the cases are functional, with ACTH-independent autonomous cortisol production being the most common. It is rare for ACC to present with markedly elevated metanephrine levels, characteristic of pheochromocytoma. We report a case of a large functioning adrenal tumour with overlapping biochemical features of ACC and pheochromocytoma. Biopsy confirmed the histopathological diagnosis of metastatic ACC.
A 17-year-old adolescent boy with biochemically raised 2-hour urinary metanephrine and normetanephrine as well as CT findings of retroperitoneal soft tissue mass and bony metastases was referred for further assessment. Apart from Ga DOTATATE PET/CT evaluation, pretargeted systemic radionuclide therapy assessment with I-MIBG scintigraphy showed unusual phenomenon of MIBG superscan. Postsurgically, restaging Tc-MDP bone scintigraphy showed typical bone superscan features. The MIBG superscan was better delineated on post-I-MIBG therapy images.
Most functional phaeochromocytomas/paragangliomas produce noradrenaline and/or adrenaline. Those that produce dopamine are rare. We describe the distinguishing clinical features of dopamine-secreting phaeochromocytomas and paragangliomas from those that secrete noradrenaline/adrenaline and the impact on their management. We present a case of a dopamine-secreting paraganglioma from our institution and review 14 case reports of dopamine-secreting phaeochromocytomas/paragangliomas published between 1984 and 2008. As observed in the literature, 80% of the tumours were extra-adrenal. Most patients presented with non-specific symptoms or mass effect without the classical presentation of catecholamine excess. The majority were diagnosed with urinary or plasma dopamine. Five patients had malignant tumours and 12 patients underwent surgical resection of the primary tumours. Unlike noradrenaline/adrenaline-secreting phaeochromocytomas/paragangliomas, dopamine-secreting tumours lack a classical presentation, are extra-adrenal and have a higher malignant potential. A routine inclusion of urinary or plasma dopamine as part of catecholamine screening in all suspected phaeochromocytomas and paragangliomas is recommended.