a Case of Unsuspected Ectopic ACTH Secretion.

Presentation Number: MON 415
Date of Presentation: April 3rd, 2017

Sanam Lathief*1, Richard J Comi1, John H Turco1 and Xiaoying Liu2
1Dartmouth-Hitchcock Medical Center, Lebanon, NH, 2Dartmouth Hitchcock Medical Center, Lebanon, NH

Abstract

Background: Ectopic ACTH Syndrome (EAS) represents about 20 % of ACTH-dependent Cushing syndrome (CS) and 10 % of all types of CS.1 Bronchial carcinoids represent the most common source of ectopic ACTH.2 We present a case of bronchial carcinoid with unsuspected EAS with unique considerations for diagnosis and management.

Case: A 72 year-old female with recent onset pre-DM, long standing HTN and > 100 pack year smoking history presented to her pulmonologist with cough and wheezing. PET CT revealed a hypermetabolic right middle lobe pulmonary nodule 1.8 x 1.9 cm increased in size compared to previous evaluation 12 years ago. Patient underwent bronchoscopy and right upper lobe endobronchial fine needle biopsy. The cytology showed clusters of neoplastic epithelial cells with spindle cell morphology positive for synaptophysin and chromogranin. Patient underwent an uneventful right upper lobe segmentectomy and pathology confirmed 2.1 cm carcinoid tumor spindle cell type. She did not receive chemotherapy or radiation.

Also noted was a 2.9 x 2.3 cm round left adrenal mass with an average Hounsfield unit below 10 and stable in size since 12 years. She was referred to us for further evaluation.

She reported a 25 year history of HTN which had been difficult to control with 4 agents. She had been treated for osteoporosis. She had an unintentional weight gain of 15 lbs over the past year, and successfully lost 10 lbs post op. She endorsed occasional anxiety but denied flushing, headaches, palpitations, diaphoresis or diarrhea.

Her initial exam was notable for HTN, truncal obesity and kyphosis. Chemistry pre-op showed mild hypokalemia of 3.3 .There was lack of suppression of serum cortisol after multiple low dose (1 mg overnight) dexamethasone suppression tests. Pre-op cortisol level post 1 mg dexamethasone was 7.3 mcg/dl. Immunohistology of the tumor showed a 2.1 cm ACTH producing bronchial carcinoid tumor with positive staining for ACTH, CD56 and synaptophysin. Post op 24 h urine 5-HIAA levels returned near normal at 8.6 ( n< 8 mg/24 h) but interestingly Chromogranin A levels returned positive at 1385 ( n< 93 ng/ml) Plasma metanephrines were normal. Pre-op renin levels were elevated at 91, but aldosterone-renin ratio was < 0.2.

Conclusion: This patient may have had bronchial carcinoid at least for 13 years but since the nodule had not changed in appearance over time was thought to be clinically not relevant. The clinical course was gradual development of resistant HTN, pre-diabetes, osteoporosis and truncal obesity. Studies of EAS from bronchial carcinoids report that recovery of HPA axis post- surgery takes an average of 3-18 months.4 However our patient exhibited a subnormal response to 1 mg low dose dexamethasone suppression testing 5 months post operatively. We plan to follow adrenal imaging to determine if there is any decrease in size of the adrenals post- surgery now that the ectopic ACTH source has been removed.

 

Nothing to Disclose: SL, RJC, JHT, XL