Duodenal somatostatinoma. Anatomic/clinical study of 12 operated cases

STUDY AIM: Duodenal somatostatinomas (DS) are very rare neuro-endocrine tumours. The aim of this retrospective and multicentric study was to report the clinical and pathological characteristics of these neoplasms in a series of 12 patients and to compare them with the literature. PATIENTS AND METHODS: From 1987 to 1998, 12 patients were operated for a DS. There were seven women and five men ranging in age from 23 to 72 years (mean age: 56.6 years). Four patients had an associated von Recklinghausen's disease, one of them with multiple endocrine neoplasia (MEN type IIa) and medullary carcinoma of the thyroíd. The surgical procedures were pancreaticoduodenectomy (n = 8), small bowel resection (n = 2), inferior gastrectomy (n = 1) and gastrojejunostomy with hepatic metastases biopsies (n = 1). The tumour was mainly located on the 2nd duodenum (n = 10), with a mean size of 2.7 cm (ranging from 0.4 to 6 cm) and with a pancreatic invasion in three patients. A metastatic disease was present at the time of diagnosis in eight patients. There were, according to Capella's classification, two patients in the groups I and II, and ten patients in group III (83%), respectively. RESULTS: There was one postoperative death after a pancreaticoduodenectomy. Three patients secondarily died from tumoral progression. Eight patients were alive, with a mean follow-up of 84 months (ranging from 5 to 290 months), at the end-point of the study. CONCLUSION: Duodenal somatostatinomas are rare neuroendocrine, generally non-functioning, well-differentiated tumours with a low grade of malignancy. The association with the von Recklinghausen's disease is frequent. The clinical somatostatinoma syndrome with diabetes, diarrhea and biliary lithiasis is rare. The treatment is surgical even with a metastatic disease. The 5-year survival rate is better than those of the pancreatic somatostatinomas or the duodenal gastrinomas.