Somatostatinoma: Clinico‐pathological features of three cases and literature reviewed

Abstract

Somatostatinoma is a rare endocrine tumor that comprises around 1% of all gastroenteropancreatic endocrine neoplasms. This paper gives an updated review on somatostatinoma and describes three sporadic cases of somatostatinoma located in the pancreas, duodenum, and jejunum. Approximately 200 case histories of somatostatinoma have been published, with the duodenum being the most frequent site, followed by the pancreas. Somatostatinomas may be sporadic or associated with neurofibromatosis type 1, Multiple Endocrine Neoplasia type 1, and Von Hippel-Lindau syndromes. Functional somatostatinomas release excessive amounts of somatostatin suppressing gallbladder motility and inhibiting the secretory activity of various endocrine and exocrine cell types. A triad of mild diabetes mellitus, cholelithiasis, and diarrhea/steatorrhoea characterizes the somatostatinoma or 'inhibitory' syndrome. Non-functional somatostatinomas tend either to be asymptomatic or to present with obstructive symptoms. These tumors are often malignant and by the time they are detected, nearly two-thirds have already metastasized to the regional lymph nodes or the liver. A comparison between our three cases and those in the literature provides useful insights into the clinical management of these patients. Interestingly, the jejunal somatostatinoma described here is the second case ever reported.

Somatostatinoma syndrome: a challenging differential diagnosis among pancreatic tumors

“…The annual estimated incidence is 1 in 40 million, with the median age at onset of 54 years (range, 24-84 years). [2][3][4] Microscopically, the kidneys showed acute tubular necrosis, which may have contributed to the final events.…”

“…The unmotivated patient only sought treatment because she was being taken care of by neighbors, reaching the medical facility Somatostatinoma derive from the somatostatin-producing delta cells of the pancreas or the endocrine cells of the digestive tract 5,6 and may be sporadic (93.1%) or familial (6.9%) in association with neurofibromatosis type 1 (NF1), multiple endocrine neoplasia type 1 (MEN1), and Von Hippel-Lindau syndromes. 4,[7][8][9][10] Most somatostatinomas (56%) originate in the pancreas and are usually functional. Extra-pancreatic somatostatinomas (44%) are located in the duodenum and occasionally in the biliary tract or small bowel.…”

“…3,33 Tumor size is a pertinent prognostic factor. 4 The diameter of 2 cm is considered the cut-off value, above which the risk of metastasis significantly increases. 26,34 Indeed, by the time they are detected, nearly 30% of duodenal and 70% of pancreatic somatostatinomas have already metastasized to the regional lymph nodes or the liver.…”

“…Extra-pancreatic somatostatinomas (44%) are located in the duodenum and occasionally in the biliary tract or small bowel. 4,[11][12][13][14][15] In most patients, these tumors are symptomatic, with variable nonspecific clinical presentation. Only a few patients may present with the typical clinical somatostatinoma syndrome, which consists of diabetes mellitus, diarrhea/steatorrhoea, and cholelithiasis.…”

Pancreatic somatostatinoma with obscure inhibitory syndrome and mixed pathological pattern

“…Little experience with chemotherapy and radiotherapy has been accumulated. Therapy with octreotide and interferon-α (IFN-α) has been shown to be beneficial in the treatment of the clinical symptoms of functional somatostatinoma (Janson, 2005;Nesi et al, 2008).…”