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Endocrine Abstracts (2019) 63 P871 | DOI: 10.1530/endoabs.63.P871

ECE2019 Poster Presentations Adrenal and Neuroendocrine Tumours 3 (70 abstracts)

A misleading presentation of auto-immune diabetes associated with somatostatinoma: a case report

Thierry Galvez 1 , Olivier Gilly 1 , Bernadette Ginert Cour 2 , Elodie Verbeke 1 , Michel Prudhomme 1 & Anne-Marie Guedj 1


1University Hospital, Nîmes, France; 2Private Practice, Nîmes, France.


Somatostatinomas are rare neuroendocrine tumors diagnosed at a rather young age (mean age at diagnosis from 40 to 60 years). Non-auto-immune diabetes may associate with somatostatinoma as a result of abnormal somatostatin secretion, which inhibits insulin release. Steatorrhea and cholelithiasis are two other classical symptoms of these tumors. Here we report a case of somatostatinoma discovered while exploring a recently diagnosed diabetes, whose clinical and biological features were compatible with type 1 diabetes. A 43 year-old lean male, with no significant (personal or family) medical history presented with canonical symptoms of insulin deficiency and diarrhea since 2 months. HbA1c was 8.1%. Anti-GAD antibodies were positive at 5.1 UI/mL (N<1). Insulin treatment alleviated all the symptoms but the persisting diarrhea. The abdominal CT scan revealed a Vater ampulla mass. Pathological examinations of endoscopic ultrasonography-guided biopsies showed a 2 cm well-differentiated G2 neuroendocrine tumor (Ki-67 was 3%). Elevated values of serum somatostatin, i.e. 88 pmol/L (N<50) were consistent with somatostatinoma. The tumor was labelled by 18F-DG PET imaging but not by Somatostatin receptor scintigraphy. Pancreaticoduodenectomy was performed and pathological examination of the resected tumor disclosed a pT3 N1 M1a, grade G2 neuroendocrine carcinoma. Insulin therapy was maintained after surgery but with reduced doses. Hence we report a misleading initial presentation of type-1 diabetes with positive anti-GAD antibodies, which was, in fact, due to the underlying presence of a somatostatinoma. Diarrhea was the only atypical symptoms, which prompted us to broaden our initial investigations. The origin of antibody production in that context is discussed.

Volume 63

21st European Congress of Endocrinology

Lyon, France
18 May 2019 - 21 May 2019

European Society of Endocrinology 

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