A 44-year-old female migrant presented with clinical and biochemical evidence of active Cushing’s syndrome (CS) on a background of Cushing’s disease managed with a brief course of ketoconazole complicated by LFT derangement and followed by transsphenoidal surgery.
3 years later, she migrated to Australia and had manifestations of disease recurrence including new diabetes, anxiety, weight gain and hypertriglyceridaemia (Table 1). MRI did not identify any residual pituitary tumour. She refused repeat IPSS, pituitary surgery and bilateral adrenalectomy. She was managed with metyrapone and cabergoline which was complicated by adrenal crisis and subsequently commenced on a hydrocortisone and metyrapone ‘block and replace’ approach. She was lost to follow-up for a year and self-ceased her medications however appeared to have resolution of her metabolic complications, raising the possibility of cyclical-CS.
She re-presented during the COVID-19 pandemic with clinically active CS. However, investigations were delayed due to her fears of contracting COVID-19 (Table 2). A repeat MRI pituitary and CT CAP failed to identify a source. Ga68-DOTATATE PET/CT demonstrated a 14mm focally avid nodule in the right pulmonary region. Fine needle biopsy with endobronchial ultrasound confirmed a bronchial carcinoid tumour expressing ACTH. MDT consensus was to proceed with resection of the lesion regardless of hormone secretion. Intra-operative pulmonary vein sampling is planned to be conducted at the time of the surgery.
Meanwhile she commenced on osilodrostat on compassionate grounds with dexamethasone and has had marked improvement of her metabolic profile and CS (Table 3).
Discussion
Cyclical-CS can be difficult to diagnose and manage and should be considered in patients with fluctuations in their clinical presentation.1 A block and replace approach may be helpful to prevent adrenal crisis.3
68Ga-DOTATATE scanning targets somatostatin receptor function and has an additional role compared to conventional imaging in the diagnosis of ectopic-CS or metastatic PitNETs.3