SFEBES2023 Featured Clinical Case Posters Section (10 abstracts)
1Lancashire Teaching Hospitals NHS Foundation Trust, Preston, United Kingdom. 2The Christie NHS Foundation Trust, Manchester, United Kingdom
Phaeochromocytoma-driven Ectopic ACTH Syndrome (EAS) is rare. We report the case of a 31-year-old female, who presented with abdominal pain and vomiting. She had clinical features of severe Cushings syndrome (proximal myopathy, bruising, refractory hypertension and acute confusion). Admission investigations revealed hypokalaemia (2.1mmol/l [3.5-5.5mmol/l]) and a 4.5cm left adrenal lesion with a bulky right adrenal on CT abdomen. She was diagnosed with hypertension (requiring 4 antihypertensives) 11 months prior, during the third trimester of pregnancy (remained refractory post-delivery without screening for secondary causes). Further investigations included non-suppression of cortisol on overnight (2649 nmol/l) and low-dose dexamethasone suppression tests (2231 nmol/l), ACTH 472 ng/l (0-46ng/l), plasma metanephrines 1.55nmol/l (<0.51nmol/l) and normetanephrines 16.9nmol/l (<1.18nmol/l). There was no pituitary lesion on cross-sectional imaging. An FDG PET/CT revealed increased uptake in both adrenals without uptake elsewhere, leading to a diagnosis of phaeochromocytoma-induced EAS. There was intense avidity of the left adrenal lesion on Ga68-DOTATATE PET/CT. Metyrapone and phenoxybenzamine were commenced and uptitrated in anticipation of urgent adrenal surgery, for which she remained an inpatient. She progressed well with resolution of confusion, normokalaemia and normotension (using less antihypertensives [5 to 2 agents]). Her ACTH showed stepwise (weekly) reductions in response to cortisol normalisation due to metyrapone treatment (472,338,188,136,113,85,29 ng/l). There were also reductions in plasma metanephrines (0.82nmol/l), normetanephrines (11.26nmol/l) and tumour size (4.5 to 3.5cm on MRI scan). The patient underwent an uncomplicated left adrenalectomy with subsequent normalisation of clinical and biochemical parameters. Histology confirmed a phaeochromocytoma (no atypical features) however ACTH staining is pending. There are important observations to derive, including that young patients with hypertension should be screened for secondary causes. The metyrapone-associated pre-operative effects were possibly mediated through the attenuation of a glucocorticoid-driven positive feedback loop on the ACTH-secreting phaeochromocytoma.