Category: Pituitary Disorders/Neuroendocrinology
Cushing’s syndrome has an incidence of 0.2–5.0 per million people per year and ectopic cushing’s account for ~1% of all those cases. Although very rare, it is a deadly disease process; approximately 28–59% of all ectopic cushing’s is from neuroendocrine tumors (NET). Here is a case of well differentiated NET with Adrenocorticotropic hormone (ACTH) production.
Methods : A 27-year-old healthy man presented with 4-month history of worsening shortness of breath, 30-pound weight loss and weakness in his proximal extremities. On exam he had moon facies, supraclavicular fullness, decreased muscle mass, anasarca and bruises on his abdomen. On initial work up he was noted to have hypokalemia and diabetes mellitus. He also had significantly elevated serum morning cortisol of 69.9ug/dL and ACTH of 356.6 (reference range 7.2–63.3pg/ml) with 24-hour urine cortisol of 21,108mcg/day (reference range 3.5–45mcg/day). A high dose (8mg) Dexamethasone failed to suppress the cortisol, it remained at 110mcg/dl from 108mcg/dl and the pituitary MRI was normal. Ectopic cushing’s was the top differential given acute onset and progression of diabetes, severe hypokalemia with no suppression of the cortisol. Further imaging with CT scan of chest, abdomen and pelvis, MRI enterography, triple phase CT scan of the liver, Endoscopic Ultrasound of the pancreas, Octreotide scan did not reveal any lesions. Subsequently, patient also underwent Inferior petrosal sinus sampling which further confirmed ectopic ACTH production. Patient continued to deteriorate rapidly, he lost an additional 50 pounds and became bedbound. Medical management was initiated due to failure to localize the tumor. Eventually, the patient underwent a Ga-DOTATATE PET/CT which revealed a nodular opacity in the anterior left lung base.
Results : Patient underwent left lower lobe resection with pathology positive for atypical bronchial carcinoid tumor with 2 lymph nodes positive for carcinoma.
Discussion : Bronchial carcinoid accounts for approximately 40% of ectopic cushing’s secondary neuroendocrine tumors. Despite these tumor’s positivity for somatostatin receptors it can be challenging to localize them with conventional functional imaging such as an octreotide scan. Often patients with Ectopic cushing’s tend to undergo many studies in efforts of localization which leads to significant delay in treatment with surgical resection.
The Ga-DOTATE PET/CT scan has been reported to have up to 94% sensitivity and ~98% positive predictive value for NET in clinical trials. This imaging modality can help localize primary tumor and progression of disease on follow-up for timely intervention.
The Ohio State University
Currently an Endocrinology fellow at the Ohio State University.
The Ohio State University
Completed medical school in Iraq followed by residency and fellowship in the United states. Now sub specializing in pituitary disorders at the Ohio State University.