SAT-046 - Recurrent Ectopic Cushing'S Syndrome Associated with Neuroendocrine Tumors

Background: Neuroendocrine tumors (NETs) can cause ectopic Cushing’s syndrome (ECS) which can be challenging to manage. Resolution of signs, symptoms, and comorbidities of ECS with pharmacotherapy alone is achieved in only 32% of patients.

Case: A 40-year-old man presented to the emergency department with 3 days of generalized weakness and palpitations. His past medical history included stage IIIA high grade large cell neuroendocrine carcinoma of the thymus complicated by ectopic Cushing’s syndrome cured with subtotal thymectomy and chemotherapy 4 years prior to presentation. Laboratory results showed severe hypokalemia of 2.4 mEq/L, prolonged QTc interval of 605 ms, cortisol level of > 119.6 mcg/dL, and ACTH level of 1754 pg/mL. Ketoconazole and metyrapone were started for hypercortisolemia. A surveillance dotatate PET-CT scan showed a new growing 0.7 cm left lower lobe subpleural nodule. A fine needle aspiration of the nodule revealed a neuroendocrine neoplasm, favoring carcinoid. He underwent left lower lung lobe wedge resection with surgical pathology confirming a neuroendocrine tumor, compatible with atypical carcinoid, and pleural nodules biopsy confirming metastatic neuroendocrine tumor. The post-operative cortisol level was 57.9 mcg/dL, and ACTH level was 680.2 pg/mL. Thus, pharmacotherapy for Cushing’s syndrome was restarted. His hypercortisolemia remained difficult to control, and he developed symptoms including extreme fatigue, weakness, insomnia, and lower extremity edema. After a multidisciplinary discussion at an adrenal tumor board, he was recommended for definitive treatment of ectopic Cushing’s syndrome with bilateral adrenalectomy. He is currently on glucocorticoid and mineralocorticoid replacement for secondary adrenal insufficiency with improvement of his symptoms and is successfully tolerating lanreotide therapy for metastatic carcinoid tumor.

Conclusion: Biochemical and clinical control of hypercortisolism in ECS associated with NETs remains difficult to achieve. Moreover, ECS can lead to complications including increased cardiovascular risk, musculoskeletal impairment, metabolic disorders, infections, thrombosis, decreased quality of life, and worse survival. In patients with recurrent ectopic Cushing’s disease who do not respond to resection of the primary NET, bilateral adrenalectomy should be considered early to eliminate the source of cortisol, improve symptoms of ECS, and prevent complications of uncontrolled Cushing’s syndrome.

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