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When Zebras Outrace Horses: Unifying Cushing's Syndrome and Anterior Mediastinal Mass

Lena Scotto, MD , Yukako Honda, MD , Melissa Weinberg, MD

March 27, 2015

A 31 year-old man presented with shortness of breath due to hypertensive emergency. Chest CT angiogram revealed an anterior mediastinal mass (Figure A). He reported easy bruising, rib fractures from minor trauma, and a 40-pound weight gain over one year. Physical examination revealed moon facies, gynecomastia, dorsocervical fat pad, truncal obesity, abdominal striae, and muscle wasting (Figure B). Laboratory studies showed:  morning cortisol 61.5 ug/dL (5-25), ACTH 190 pg/mL (6-50), and 24 hour urine free cortisol 4739 ug (4-50). After an 8-mg overnight dexamethasone suppression test, morning cortisol was 60.2 ug/dL and ACTH was 227 pg/mL.  Mass biopsy revealed thymic neuroendocrine carcinoma. ACTH tissue staining was positive (Figure C).


Figure A


Figure B


Figure C


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Authors: Lena Scotto, MD[1], Yukako Honda, MD[2], Melissa Weinberg, MD[3]


[1] Stanford University Medical Center, Department of Anesthesia, Palo Alto, CA

[2] California Pacific Medical Center, Department of Medicine, San Francisco, CA

[3] California Pacific Medical Center, Department of Endocrinology, San Francisco, CA