Session: SUN 29-49-Congenital Adrenal Hyperplasia & Ectopic Cushing's
Poster Board SUN-41
Clinical case: A non-smoking 44 year-old man experienced progressive central obesity, proximal muscle weakness, high blood pressure and emotional lability during the last 6 months. At admission, recent left femoral vein thrombosis and silent bilateral pulmonary emboli were found.
Investigation: Elevated cortisoluria (>10xULN), ACTH level (112 pmol/L), hypokalemia, and poor dexamethasone suppression suggested ectopic ACTH source despite possible pituitary lesion at MRI. ACTH (t0:59.0 pmol/L;peak t15 min:151.9 pmol/L) and cortisol were stimulated by desmopressin but not by CRH. A low central-to-peripheral ACTH gradient was found during inferior petrosal venous sinus sampling with desmopressin. Combination of ketoconazole and metyrapone were necessary to control hypercortisolism. The interpretation of CT-scan of thorax and indium-111 octreoscan were complicated by the presence of multiple pulmonary emboli; a right 4 cm thoracic cage lipoma did not show any uptake with FDG-PET and no other thoraco-abdominal lesion was identified. A second indium-111 octreoscan two weeks later showed a persistent uptake in a 3 mm left inferior lobe lung nodule that was first interpreted as a vascular thrombus; other sites of uptake had regressed during therapy with low-molecular weight heparin. A left inferior lobectomy was performed and plasma cortisol and ACTH decreased abruptly after the surgery requiring hydrocortisone replacement. A diagnosis of lung carcinoid was expected based on the progressive Cushing’s syndrome and absence of activity of lesion on FDG-PET; a neuroendocrine large-cell carcinoma with intense ACTH expression was found at pathology with metastasis in 2/4 resected lymph nodes. The patient was referred to pulmonary oncology team for adjuvant therapy.
Conclusion : Neuroendocrine large-cell carcinoma is an infrequent subtype of bronchopulmonary neuroendocrine tumors, representing less than 1% of them. Our literature review indicates that this is the second case report of ectopic ACTH syndrome and the first of positive response to desmopressin test related to a large-cell lung carcinoma. This case illustrates the diversity of clinical and phenotypic behavior of ACTH secreting neuroendocrine tumors.
Disclosure: AL: Investigator, Novartis Pharmaceuticals, Editor, Up To Date, Consultant, Novartis Pharmaceuticals. Nothing to Disclose: VP, IF, AR, LGS, RC, RA
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