Ectopic corticotropin-releasing hormone syndrome caused by pancreatic neuroendocrine tumor localized by 68Ga-DOTATATE PET/CT
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A 23-year-old female patient presented with anxiety, insomnia, hirsutism, skin pigmentation, obesity, and muscle weakness for 7 months. The results of serum ACTH, low-dose dexamethasone suppression tests (DSTs), high-dose DSTs, and inferior petrosal sinus sampling implicated that the symptoms might be caused by ectopic Cushing syndrome (ECS), due to the secretion of adrenocorticotropin hormone (ACTH) or corticotropin-releasing hormone (CRH). In order to locate the ectopic origin, the patient underwent 68Ga-DOTATATE and 18F-FDG PET/CT. 68Ga-DOTATATE PET/CT imaging(a-d) revealed one lesion on pancreas (d, arrow) and multiple lesions on liver. While the pancreas showed no abnormality on 18F-FDG PET/CT imaging (e-h, arrow), and the lesions on the liver were fewer and smaller than that on 68Ga-DOTATATE. Neuroendocrine tumors (NET, Ki67 > 15%) were confirmed by histopathological results of biopsy on liver and pancreas. Immunohistochemical analysis was positive for CRH and negative for ACTH.
The clinical presentations of ectopic CRH syndrome might be similar to that of ectopic ACTH syndrome, so the differential diagnosis of these two diseases is important. Commonly, the tumors associated with ectopic CRH secretion are pheochromocytoma, medullary thyroid carcinoma, and prostate cancer . Ectopic ACTH and CRH co-secreting tumor and ectopic ACTH secreting tumor detected by 68Ga-DOTA-peptide PET/CT were described on case reports [2, 3], but ectopic CRH-secreting NET observed by 68Ga-DOTA-peptide PET/CT has never been reported. 18F-FDG is less sensitive to high-grade NET, and 68Ga-DOTATATE PET/CT could plays a good complementary role to identify the source of ectopic CRH secretion.
This report was supported by the National Natural Sciences Foundation of China (No. 81371588, No. 81101074).
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