[Obscure gastrointestinal bleeding due to duodenal infiltration of a non-functioning pancreatic neuroendocrine tumor diagnosed by capsule endoscopy: a case report].

Non-functioning pancreatic neuroendocrine tumors (PNETs) are infrequent slow-growing, clinically-silent tumors. They are incidentally detected and some of them may present in advanced stages with local involvement of surrounding structures. The diagnostic accuracy of endoscopio ultrasound (EUS) and fine needle aspiration (FNA) biopsy is significantly lower in neuroendocrine tumors (46.7%) compared with adenocarcinoma (81.4%) and other histologies (75%). Therefore, preoperative diagnosis is very difficult. Exceptionally, hey present with gastrointestinal bleeding. We present a case of a non-functioning PNET initially diagnosed as cystic serous tumor of pancreas with EUS and FNA biopsy. Two years later patient presented obscure gastrointestinal bleeding due to duodenal infiltration. Diagnosis was made by capsule endoscopy.