Endocrine Abstracts

Fifty-three year old male presented to gastroenterologist with retrosternal pain and dysphagia. On gastroscopy a 2 cm soft sub-pedunculated polypoid mass in the lower oesophagus was identified and on biopsy it was confirmed as adenocarcinoma. CT scan confirmed the finding but additionally identified 20mm right adrenal “incidentaloma” with mild calcification and reassuring imaging characteristics, further supported by a low uptake on 18-FDG PET-CT. He underwent Ivor Lewis oesophagectomy without endocrine assessment. However 2 years later a repeat CT scan revealed a mild increase in the size of adrenal lesion and the patient was referred to the Endocrine team to assess its functionality. The patient was asymptomatic but the urinary free noradrenalin was persistently elevated with normal adrenaline and dopamine. Surprisingly, MIBG scan showed intense uptake within the gastric pull-up with normal uptake in the adrenal glands. Further biochemistry revealed elevated plasma and urinary normetanephrine confirming catecholamine hypersecretion. ⁶⁸Gallium-DOTATATE scan showed intense uptake in the right adrenal nodule and excluded DOTATATE avidity elsewhere. Right adrenalectomy was performed after appropriate alpha and beta blockade and histology confirmed phaeochromocytoma (immunohistochemistry positive with chromogranin and synaptophysin) with PASS (Phaeochromocytoma of the Adrenal gland Scoring Scale) score of two. Oesophageal uptake in MIBG scan proved to be a red herring. This case reminds us of two interesting points. Firstly, although most adrenal phaeochromocytomas secrete both norepinephrine and epinephrine, about a third exclusively produces norepinephrine and a much smaller proportion exclusively produce epinephrine. Secondly DOTATATE scan is generally found to be more sensitive and specific than MIBG scans and there is some association in literature linking false negative MIBG scans with SDHB mutations, high frequency to develop metastatic disease, extra-adrenal location and hypersecretion of normetanephrine or norepinephrine.