Duodenal somatostatinoma: a case report and review of the literature

Somatostatinoma: Beyond neurofibromatosis type 1 (Review)

Somatostatinoma is a tumour mainly originating from pancreas or duodenum; overall with an incidence of 1/40 million persons. We introduce a narrative review of literature of somatostatinoma including the relationship with neurofibromatosis type 1. Clinical presentation includes: Diabetes mellitus, cholelithiasis, steatorrhea, abdominal pain, and obstructive jaundice while papillary tumour may cause acute pancreatitis. The neoplasia may develop completely asymptomatic or it is detected as an incidental finding during an imaging or a surgical procedure. It may be sporadic or associated to genetic backgrounds especially for duodenal localisation as neurofibromatosis type 1 (NF1 gene with malfunction of RAS/MAPK pathway) or Pacak-Zhuang syndrome (EPAS1 gene encoding HIF). Surgery represents the central approach if feasible but the prognostic depends on location, and grading as indicated by WHO 2017 classification of neuroendocrine tumours. Previously known as Von Recklinghausen disease, neurofibromatosis type 1, the most frequent neurocutaneous syndrome, is an autosomal dominant disorder including: Café-au-lait spot, skin fold freckling on flexural zones, and neurofibromas as well as tumours such as gliomas of optic nerve, gastrointestinal stromal tumours (GISTs), iris hamartomas and brain tumours. Duodenal somatostatinoma is associated with the syndrome which actually involves more often a duodenal tumour of GIST type than a somatostatin secreting neoplasia. Other neuroendocrine tumours are reported: Gastrointestinal NENs at the level of rectum or jejunum and pheocromocytoma. Overall, one quarter of subjects have gastrointestinal tumours of different types. Somatostatinoma, when not located on pancreas but in duodenoum, may be registered in subjects with neurofibromatosis type 1 most probably in addition to other tumours. Overall, this type of neuroendocrine tumour with a challenging presentation has a poor prognosis unless adequate radical surgery is promptly offered to the patient.

Duodenal somatostatinoma presenting as obstructive jaundice with the coexistence of a gastrointestinal stromal tumour in neurofibromatosis type 1: a case with review of the literature

Somatostatinomas are rare neuroendocrine tumours, mostly located in the pancreas or duodenum, with an estimated incidence of 1 in 40 million. Duodenal somatostatinomas (DSs) are usually found in association with neurofibromatosis type 1 (NF1), tuberous sclerosis and Von Hippel-Lindau syndrome. Gastrointestinal stromal tumours (GIST) have also been described in NF1, but the association with somatostatinoma is very uncommon. We report the case of a patient with NF1 who presented with obstructive jaundice due to multiple firm nodules around the ampulla of Vater. A pancreaticoduodenectomy was performed and revealed a 1 cm duodenal/ampullary mass which stained positive for somatostatin, together with a GIST also found on the duodenal wall. Despite its rarity, ampullary somatostatinomas should be considered in the differential diagnosis of biliary tract dilation in patients with NF1.

Somatostatinoma of the Ampulla: An Incidental Postoperative Finding Following Colorectal Cancer Resection

Somatostatinoma of the gastrointestinal tract is a rare finding, especially arising from the ampulla of Vater. We present a man recently diagnosed with rectal adenocarcinoma who was found on imaging to have an ampullary mass. Histology and immunohistochemical staining of the biopsied tissue were consistent with a nonfunctioning somatostatinoma. The patient had neurofibromatosis, which have been reported in patients with ampullary somatostatinomas. Our case highlights the importance of gastrointestinal findings in those with underlying genetic conditions.