Pancreatic somatostatinoma

Von Recklinghausen's disease associated with duodenal somatostatinoma: contrast of duodenal versus pancreatic somatostatinomas

A case of Von Recklinghausen's disease with duodenal somatostatinoma is reported. A search of the world's literature revealed 27 patients with Von Recklinghausen's disease associated with an immunohistologically proved duodenal somatostatinoma. Twenty-nine cases of duodenal somatostatinoma not associated with Von Recklinghausen's disease and 32 cases of pancreatic somatostatinomas have been identified for comparison. While their histology may be similar in many respects, the duodenal and pancreatic somatostatinomas show significant differences, especially in hormonal and growth behaviors. In contrast to its pancreatic counterpart, the duodenal somatostatinoma is frequently associated with Von Recklinghausen's disease, is seldom associated with a recognizable "somatostatin syndrome," often contains psammoma bodies, and is less frequently associated with demonstrable metastases at the time of operation.

Gallstones during octreotide therapy

Gallbladder stones (GBS) are found in up to 50% of patients receiving octreotide, but the reported prevalence of cholecystolithiasis in patients treated with octreotide is variable and little is known about gallstone incidence, composition, pathogenetic mechanisms, dissolvability, and primary prevention. Octreotide treatment apart, in industrialised societies most GBS are mixed in composition, cholesterol-rich (arbitrarily greater than 70% cholesterol by weight), radiolucent (70%), and, given a patent cystic duct (70%), dissolvable in bile rendered unsaturated in cholesterol by oral ursodeoxycholic (UDCA) +/- chenodeoxycholic (CDCA) acid treatment. They form when (1) GB bile becomes supersaturated with cholesterol (as the molar ratio of cholesterol to phospholipids in biliary vesicles approaches 1:1, the vesicles become unstable); (2) there is an imbalance between pro- and anti-nucleating factors, which favors cholesterol crystal precipitation; and (3) there is stasis within the GB as a result of altered motor function and/or excess mucus that traps the crystals. These changes may be associated with altered (4) biliary bile acid composition (more DCA and less CDCA than normal), and/or (5) phospholipid fatty acid composition (arachidonyl-rich lecithin acting as a substrate for mucosal prostaglandin synthesis which, in turn, may influence both gallbladder motility, and mucus glycoprotein synthesis and secretion). During octreotide treatment, meal-stimulated cholecystokinin (CCK) release is impaired leading to GB hypomotility, but little is known about the effects of octreotide on biliary cholesterol saturation, crystal nucleation time, mucus glycoprotein concentration, bile acid or phospholipid fatty acid composition. Most, but not all, reports suggest that the prevalence of GBS in octreotide-treated patients is considerably greater than that in age-, sex-, and weight-matched controls, but proof (by pre-treatment and on-treatment ultrasound) that the GBS were absent before, but developed during, therapy is not always available. Furthermore, there are few data on analysis of GBS composition in patients developing stones during treatment, although initial reports suggest that octreotide-associated GBS are also radiolucent, cholesterol-rich, and dissolve with oral bile acid treatment. Maximum GBS attenuation values, measured in Hounsfield Units (HU) by localized computerized tomography scanning of the GB, predict stone composition and dissolvability: GBS with scores of less than 100 HU are cholesterol-rich and dissolve well with oral bile acid treatment. However, preliminary results in 11 acromegalic patients treated with 200 to 600 micrograms octreotide/d for 29 to 68 months show that the HU scores range from 23 to 490 (mean +/- SEM, 116 +/- 41), suggesting that at least four of these 11 patients have non-cholesterol stones.(ABSTRACT TRUNCATED AT 400 WORDS)

Pancreatic somatostatinoma: a case report and review of the literature

A 56-year-old man underwent distal pancreatectomy, splenectomy, and partial resection of the splenic flexure of the colon because of tumor in the tail of pancreas and the splenic hilus. The patient presented with symptoms of general malaise, anorexia, weight loss, mild diarrhea, and borderline diabetes mellitus, although there was no cholelithiasis. The diagnosis remained unclear until immunohistochemical studies of the resected specimen revealed somatostatin and synaptophysin, suggesting a somatostatinoma. Twenty-three reported cases of pancreatic somatostatinoma are reviewed and their clinical features discussed. The role of immunohistochemical studies in the diagnosis of somatostatinoma is described.

Anatomic distribution of pancreatic endocrine tumors

Pancreatic endocrine tumors are grouped together by their common histologic, cytochemical, and ultrastructural features. Although useful conceptually, this paradigm has been unable to predict the anatomic location of different tumor types. Successful surgical excision of these tumors would be facilitated by an improved understanding of their anatomic distribution. Based on the available data, a bimodal distribution of pancreatic endocrine tumors was identified. Cluster 1 (gastrinomas, pancreatic polypeptide (PP)-secreting tumors, somatostatinomas) had 75% of tumors to the right of the superior mesenteric artery, whereas cluster 2 (insulinoma, glucagonoma) had 75% of tumors to the left of the superior mesenteric artery (p less than 0.05). This distribution is similar to that distribution predicted based on the volume density of the corresponding islet cells for insulinoma, glucagonoma, and PP-secreting tumors, but not for somatostatinoma. These findings suggest that pancreatic endocrine tumors are derived from similar cytologic precursors as pancreatic islet cells, and their distribution may be a consequence of embryologic development from either the ventral (cluster 1) or dorsal (cluster 2) pancreatic buds.

Somatostatinoma: a case report and review of the literature

Somatostatinomas are rare endocrine tumors that were first described in 1977. In addition to the present case report, there have been 31 cases reported in the literature. We have reviewed the literature to integrate the symptoms, physical findings, diagnostic tests, treatment, and length of survival of these patients. Although the symptoms that occurred in the majority of cases were those that are seen in most patients with intra-abdominal neoplasms, symptoms relating to the presence of excess circulating somatostatin--diabetes, maldigestion, and cholelithiasis--were frequently seen. Physical findings and the results of diagnostic tests were usually nonspecific. The majority of the patients underwent radical surgical procedures (Whipple procedure or pancreatic resection). The pancreas was the most frequent site of involvement (21/31 cases), but primaries in the duodenum, ampulla of Vater, cystic duct, and jejunum have been described as well. Metastases were most frequently seen in the liver and lymph nodes. Chemotherapeutic agents were administered to 10 patients, usually as adjuvant therapy, and appear to be useful in treating recurrent and metastatic disease. The one-year survival of these patients is 48%, which is better than that for patients with carcinoma of the pancreas or biliary tree. Therefore, it is important that the diagnosis of somatostinoma be made so that the patient may be treated accordingly and followed by serial somatostatin levels for evidence of metastasis or recurrent disease.

Malignant somatostatinoma presenting with diabetic ketoacidosis

High circulating levels of somatostatin (SRIF) were detected in a patient with a metastatic tumour after development of diabetic ketoacidosis (DKA). Fasting insulin and C-peptide levels were markedly suppressed, but plasma glucagon was not suppressed below normal. Progressive cachexia ensued; at autopsy a poorly differentiated non-small cell neuroendocrine carcinoma metastatic to liver was found. Small gallstones were noted. Electron microscopy of tumour tissue showed neurosecretory granules and tonofilament bundles. Immunohistochemical staining of tumour cells was diffusely positive for carcinoembryonic antigen, bombesin-like immunoreactivity, and calcitonin with focal immunoreactivity for SRIF, serotonin, neuron-specific enolase, chromogranin, and epithelial membrane antigen. Column chromatography of plasma and tumour extract revealed five or more peaks of material with SRIF-like immunoreactivity (SRIF-LI): predominantly SRIF-28 and intermediates in tumour extract, and SRIF-14 and an intermediate between SRIF-28 and SRIF-14 in plasma, DKA in this case of somatostatinoma syndrome may reflect differential effects of tumour production of larger molecular weight SRIF forms on insulin and glucagon secretion.