Ectopic Cushing's Syndrome Presenting As Refractory Hypokalemia

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 29-49-Congenital Adrenal Hyperplasia & Ectopic Cushing's
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-45
Dinesh Edem*1, Priyanka Iyer1, Katherine Fallano1 and Esther Irina Krug2
1Johns Hopkins University/ Sinai Hospital of Baltimore, Baltimore, MD, 2Johns Hopkins University/ Sinai Hosp of Baltimore, Baltimore, MD
Introduction:Ectopic ACTH production represents approximately 10% of the total cases of Cushing's Syndrome (1); with <1% caused by pancreatic neuroendocrine tumors (pNET). Optimal approach to diagnosis and management of these tumors is not well defined.

Case: An 82 yr old previously asymptomatic woman with known osteoporosis presented with a cervical spine fracture after sustaining a fall. On exam she had no cushingoid features except for mild plethora. Laboratory studies were notable for persistent hypokalemia (K=2.8 mmol/L) despite aggressive replacement, new onset hyperglycemia and metabolic alkalosis. Cortisol and ACTH levels were elevated at 71.9 mcg/dl and 187 pg/ml respectively. Cortisol level after 8 mg overnight dexamethasone suppression   was 123 mcg/dL. CT scan of the abdomen revealed a 6 cm x 5 cm pancreatic mass and several liver lesions. An octreotide scan showed intense uptake in the pancreas and liver. Liver biopsy revealed metastatic small cell carcinoma with histopathologic staining and tumor markers suggestive of a pNET. She was felt not to be a candidate for surgical resection. Treatment with ketoconazole (400mg TID) initially resulted in decrease in cortisol levels and improvement of hypokalemia and hyperglycemia.  Refractory hypercortisolemia recurred within several days despite ongoing treatment. Octreotide LAR (40 mg IM) was administered with no clinical response.  She received one dose of mifepristone but was unable to continue due to inability to swallow whole tablets. As her condition declined, her family decided to pursue comfort care only and the patient died after 1 month of hospital stay.

Discussion: Pancreatic Neuroendocrine tumors can cause severe ectopic Cushing’s Syndrome. Since cushingoid features are usually absent, its prevalence may be underestimated. Refractory hypokalemia may point towards diagnosis. In patients with unresectable tumors response to currently available medical therapies remains poor. Optimal treatment strategy and role of glucocorticoid receptor antagonists and its effects on morbidity and mortality requires further study.

(1) Ilias et al. 2005 Cushing’s syndrome Due to Ectopic Corticotropin Secretion: Twenty Years’ Experience at the National Institutes ofHealth. J Clin Endocrinol Metab 90(8): 4955.

Nothing to Disclose: DE, PI, KF, EIK

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