Five Cases of Somatostatinoma: Clinical Heterogeneity and Diagnostic Usefulness of Basal and Tolbutamide-Induced Hypersomatostatinemia*

Abstract

Five cases of somatostatinoma are reported, four being primarily located in the pancreas and one in the duodenum. The diagnosis was based upon the histological and immunochemical characteristics of tumoral and metastatic tissue. A marked clinical heterogeneity was noted: one patient presented with gallstones, steatorrhea, and diabetes, two patients suffered from severe hypoglycemic attacks, and two cases were admitted for obstructive jaundice. This varying symptomatology was related to differences in the circulating levels of biologically active somatostatin and to a variable cellular composition of the tumor. In all cases, a basal and/or tolbutamide-induced hypersomatostatinemia was measured. It is concluded that the clinical and hormonal features of the earlier defined somatostatinoma syndrome are no requisite for the diagnosis of somatostatinoma; the analysis of plasma somatostatin immunoreactivity might lead to a higher detection rate of this endocrine tumor.

Somatostatin-producing neuroendocrine tumors of the duodenum and pancreas: incidence, types, biological behavior, association with inherited syndromes, and functional activity

“…They did not survive for more than 1 year, despite the extensive surgery and chemotherapy. This observation confirms previously published results (Pipeleers et al 1983, Zamboni et al 1990, Berkel et al 2004, Capella et al 2004, Ohike et al 2004, Nassar et al 2005.…”

“…In addition, five patients with MEN1 were included. Some of the patients were included in earlier studies investigating the histopathology and genetics of NETs (Pipeleers et al 1983, Ohike et al 2004, Sipos et al 2004, Anlauf et al 2005, Kapran et al 2006.…”

“…In an overview by Tanaka et al (2000) and the report by House et al (2002), none of the patients showed any symptoms of the somatostatinoma syndrome. In a series of five patients with SOM-NETs, Pipeleers et al (1983) described three patients with an incomplete somatostatinoma syndrome. These authors considered the extreme variation to be due to marked differences in the circulating levels of biologically active somatostatin.…”

Insulin and Somatostatin Releasing Islet Cell Tumor Caused Hypoglycemia.

“…This tumor caused hypoglycemia with an apparently normal insulin level. In addition, we found 6 similar cases of pancreatic somatostatinoma in a literature review, all of which recurred hypoglycemic attacks (6)(7)(8)(9)(10).…”

Diffuse somatostatin-immunoreactive D-cell hyperplasia in the stomach and duodenum

“…Pathological increases of somatostatin serum levels of between 40-fold and 100-fold greater than normal values are known from somatostatinomas (9000-1300 pg/ml). These were accompanied by very low basal serum growth hormone levels (0.8 ng/ml), without any response to stimulation in hypothalamic and pituitary functional tests (20,21).…”