Endocrine Abstracts

We describe the case of a 52-year-old female, with a body mass index of 32 kg/m² and without significant co-morbid illness who initially presented acutely, with self-resolving abdominal pain. During that admission, an abdominal computed tomography (CT) scan demonstrated a right-sided heterogeneous and contrast enhancing adrenal mass (measuring 59×41 mm) with a 15 mm focus of cystic degeneration. Based on the scan appearances, the patient was suspected as having a phaeochromocytoma and referred to our centre. She did not report any symptoms of catecholamine excess however was found to be hypertensive. Initial blood test screening revealed a diagnosis of type 2 diabetes mellitus (glycated haemoglobin 55 mmol/mol). She underwent biochemical screening for adrenal hormone excess with normal values of plasma metanephrines (<38 pmol/l [0-510]), normetanephrines (233 pmol/l [0-1180]), 3-methoxytyramine (<75 pmol/l [0-180]), aldosterone (161 pmol/l with an aldosterone to renin ratio of 146) and a normal post-overnight dexamethasone suppression test cortisol (<50 nmol/l). On the basis of initial investigations, the patient was worked up for the possibility of a ‘non-functioning’ phaeochromocytoma and underwent functional imaging with positron emission tomography (PET) scans; she initially underwent a fluorodeoxyglucose (FDG) and then a gallium⁶⁸ dotatoc PET scan. Both PET scans showed moderate-to-high intensity localised tracer uptake and consequently the patient was diagnosed as having a non-functioning phaeochromocytoma. Her hypertension was managed with doxazosin which was uptitrated to achieve consistent normotension. She underwent a right-sided robot-assisted laparoscopic adrenalectomy with an uneventful post operative course. A short synacthen test performed a week after surgery was normal with a peak cortisol of 780 nmol/l (>450). Postoperative histopathology and immunohistochemistry demonstrated features consistent with an epithelioid angiomyolipoma of the adrenal gland, without any evidence of necrosis, mitotic activity or vascular invasion. There was strong positivity for Cathepsin K and alpha smooth muscle actin (SMA) and negativity for Human Melanoma Black 45 (HMB45). Cytokeratins, neuroendocrine markers, CD34 and signal transducer and activator of transcription 6 (STAT6) were also negative. The Ki67 was less than 1%. Our case demonstrates a rare and unusual benign adrenal tumour type which had the preoperative radiological appearances of a phaeochromocytoma. Angiomyolipomas (AMLs) usually consist of smooth muscle cells, adipose tissue, and thick-walled blood vessels and are commonly found in the kidneys. Extrarenal AMLs are rare with the liver being the commonest site. There have been less than 30 cases reported in the English literature for adrenal AML.