A Case of Acute Psychosis as Manifestation of Ectopic ACTH Producing Pancreatic Neuroendocrine Tumor

Abstract

Abstract Introduction: Ectopic adrenocorticotrophic hormone (ACTH) producing Pancreatic Neuroendocrine Tumor (p-NET) are extremely rare with incidence of 1.2% and confer a poor prognosis (5-year survival <20%). Case Report: 31-year old female with diabetes mellitus type 2 (DM-2) and hypertension (HTN) was found to be severely hypokalemic on routine labs and was sent to the Emergency Department for potassium replacement. Vitals; BP:139/87 mmHg, HR:108 bpm, RR:18, T:37°C and saturating 98% on ambient air. Examination revealed cushingoid features; hyperpigmented face, bilateral upper extremity pigmented papules, proximal muscle weakness, acanthosis nigricans, violaceous abdominal striae, truncal obesity, ecchymoses, bilateral lower extremity edema, memory impairment and anxiety. Initial labs; BG: 289 mg/dL, HbA1c: 9.5%, K: 2 mmol/L (N 3.5-5.2), WBC: 12.5 k/μL (N 4-10.8), Cortisol >150 mcg/dL (N 5-23), TSH: 0.325 μIU/mL (N 0.45-4.5), and FT4: 0.69 ng/dL (N 0.82-1.77). Diagnosis of Cushing’s syndrome was made based on elevated cortisol level and confirmed with elevated 24-hour urinary free cortisol: 13,294 μg (N<45), midnight salivary cortisol >15 ug/dL (N 0.09-1.5) and 1 mg dexamethasone suppression test (Cortisol >150 mcg/dL, ACTH: 621 pg/ml). Additional labs showed Chromogranin A: 717 ng/mL (N 0-160). She was started on prophylactic Enoxaparin & Trimethoprim/Sulfamethoxazole and treated with Spironolactone, Basal/Bolus insulin, and Ketoconazole for hypercortisolemia. Pituitary MRI was negative for pituitary adenoma. Abdominal/Pelvic CT scan demonstrated a solid 5 cm pancreatic head mass with innumerable haptic metastases consistent with metastatic p-NET which was confirmed on PET-CT Ga68 Dotatate scan. Liver biopsy was positive for a well differentiated p-NET with ki-67 <5% and negative ACTH staining. Hospital course was complicated by fluctuating cortisol levels with intermittent psychotic manifestations despite up-titration of Ketoconazole, addition of Octreotide as well as anti-psychotics. She later developed transaminitis on maximum dose of Ketoconazole and thus underwent laparoscopic total adrenalectomy for treatment of her hypercortisolemia. Post-operatively, she was started on Hydrocortisone & Fludrocortisone and Spironolactone was discontinued. She was transitioned to monthly Lanreotide and treated with Capecitabine and Temozolomide with adequate therapeutic response and subsequent down trending of her Chromogranin A: 188 ng/mL and ACTH: 228 pg/ml levels. Currently, she is doing well with significant improvement of her DM-2, HTN, psychiatric symptoms and overall clinical status. Conclusions: Symptoms of ectopic Cushing’s syndrome may be delayed, however given the rare and aggressive nature of ACTH producing p-NET, timely diagnosis, prophylaxis and individualized treatment approach is crucial in achieving favorable prognosis.