6888 Sequencing Endocrinologic And Oncologic Treatments For A Patient With A Metastatic High-Grade Neuroendocrine Tumor And The Ectopic Acth Syndrome

Abstract Disclosure: C. Villatoro Santos: None. C. Alvarado Nieves: None. T. Enzler: None. R.J. Auchus: None. Ectopic ACTH syndrome (EAS) from neuroendocrine tumors (NETs) is a rare cause of hypercortisolism. We present a patient with a metastatic NET and severe cortisol-associated morbidities that posed the dilemma of sequencing oncologic and endocrinologic care requiring multispecialty coordination. A 55-year-old female presented with severe leg edema, weakness, hypokalemia, new-onset hypertension, and 35-lb weight gain two months prior to diagnosis. Examination showed BP 189/68, facial plethora, dorsocervical fullness, and 3+ pitting edema up to the thighs. On second hospitalization for hypokalemia, baseline plasma ACTH was 206 pg/mL and AM serum cortisol after 1 and 8 mg of dexamethasone at bedtime was 61 and 84 μg/dL (<1.8 μg/dL), respectively. An MRI pituitary showed a 5 mm hypoenhancing lesion. A body CT showed hepatic masses, largest measuring 5.7 cm, a 4 cm heterogeneous pancreatic tail mass, and a 2.3 cm left adrenal nodule. The first priority was hypokalemia, which normalized with amiloride 20 mg/d, spironolactone 400 mg/d, and KCl up to 160 mEq/d. She underwent CT-guided biopsy of the largest liver lesion, and pathology was consistent with a metastatic high-grade NET (Ki67 49%). She was transferred to our institution with a serum cortisol of 171 μg/dL. The second priority of glucocorticoid excess was addressed with metyrapone 1,500 mg/d, which lowered serum cortisol to 42.3 μg/dL on day 16; however, she developed uncontrolled hyperglycemia requiring insulin. She was transitioned to mifepristone 300 mg/d on hospital day 18 with subsequent improvement in glycemia. Once her EAS was controlled, cytoreductive surgery with resection of pancreatic mass and largest liver lesion was planned for the third priority of tumor burden but was canceled after discovery of osseus metastasis. She underwent bilateral adrenalectomy on day 26, 3 d after stopping mifepristone, for chronic control of EAS. Pathology showed a 1.6 cm metastatic high-grade NET in the left adrenal. She had a month of prophylactic anticoagulation after discharge on day 29. Outpatient, she remains normotensive and euglycemic with hydrocortisone and fludrocortisone and on chemotherapy with capecitabine/temozolomide with good tolerability. A 68Ga-DOTATATE PET-CT scan for treatment planning showed tumor uptake involving the liver, bones, and pancreatic tail (Krenning of 4) and lanreotide monthly was added to current capecitabine/temozolomide with future consideration of carboplatin/etoposide and possible addition of checkpoint inhibitor if treatment failure. Given somatostatin receptor positivity, Lu-177-DOTATATE treatment will also be a future option. The severe hypercortisolemia of EAS can be rapidly fatal and must be controlled prior cancer-directed therapy. This case illustrates effective sequencing of therapy to control hypokalemia, hyperglycemia, and long-term management of the EAS prior to chemotherapy. Presentation: 6/2/2024