Endocrine Abstracts

68 years old male was admitted with cough and fever during the second UK covid surge. Recent new diagnosis of hypertension and diabetes with worsening psychotic symptoms on background of schizophrenia. Noted previous hypernatremia, hypocalcemia, hypomagnesemia along with marked refractory hypokalemia and metabolic alkalosis. Cushing’s syndrome phenotype was not noted. Failed to suppress cortisol during an overnight dexamethasone suppression test with plasma cortisol remaining 1045 nmol/l. 24-hour urinary free cortisol was 3536 nmol/l and midnight plasma cortisol was 856 nmol/l. Plasma ACTH 275 ng/l with low dose dexamethasone suppression test not revealing fall in cortisol (remaining at 900 nmol/l) Pituitary MRI was normal, CT chest, abdomen and pelvis showed bulky adrenal glands, multiple broncho vascular lung nodules and right lower lobe consolidation and a left supraclavicular soft tissue density of 2 cm which did not show significant DOTATATE uptake. Patient was commenced on metyrapone which was gradually up titrated to 1.5 mg TDS to achieve a mean plasma cortisol of around 300 nmol/l for presumed Cushing’s. Eplerenone was added for hypokalemia. He was gradually switched to high-dose metyrapone and 4mg prednisolone as block and replace regime. He was started on rivaroxaban 10 mg for DVT prophylaxis as well as prophylactic co-trimoxazole. Histology of left supraclavicular lymph node was suggestive of a well differentiated neuroendocrine tumor with Ki-67 proliferation index of 2%. It stained negative for ACTH and positive for TTF-1, chromogranin and synaptophysin. Plasma calcitonin was raised at 28,000 pg/ml thus confirming a diagnosis of medullary thyroid cancer with probable ectopic ACTH secretion. Planned total thyroidectomy had to be abandoned due to very advanced disease and medical treatment with Cabozantinib was commenced. Despite a good clinical response to cabozatinib due to low tolerance mainly related to abdominal pains patient was switched to a selective RET inhibitor selpercatinib. This patient is a case where patient preferences and choices alongside a provisional diagnosis treatment has been successful in convoluted patient journey to achieve positive outcomes.