Somatostatinoma constitutes an uncommon neuroendocrine neoplasm that originates from the pancreatic or gastrointestinal tissue. It may lead to abnormally high levels of somatostatin, produced from delta (D) cells.
Somatostatinomas are tumors originally generated from pancreatic or gastrointestinal tract cells and are expected to produce considerable symptomatology in the majority of the patients. Depending on the specific clinical presentation, somatostatinomas can be classified under two distinguishable categories: secretory, causing the inhibitory syndrome, and non-secretory ones, that remain asymptomatic and may be diagnosed incidentally or lead to enteric obstruction.
Those suffering from tumors that secrete somatostatin initially present with the aforementioned inhibitory syndrome. This entails a multitude of reported symptoms, such as diabetes mellitus that can be exacerbated even to a state of hyperglycemic ketoacidosis, cholelithiasis, and weight loss. Steatorrhea or diarrhea episodes are common and individuals tend to report up to ten foul-smelling stools per day; achlorhydria or hypochlorhydria is a frequent finding but does not usually lead to any remarkable complaint. Hormone-secretory somatostatinomas are primarily found in the pancreas; if they originate from the gastrointestinal tract (GIT), they are mainly large lesions, more than 4 cm . Anorexia, vomiting and abdominal discomfort may co-exist.
With regard to non-secretory, or non-functional, somatostatinomas, they usually arise from the duodenum and manifest with duodenal obstruction, cholelithiasis, abdominal pain, jaundice of obstructive nature and bleeding of the GIT . As a rule, they constitute tumors of a smaller diameter than their secretory counterparts and can even be asymptomatic. At the time of diagnosis, approximately 70% of these lesions will have metastasized to the regional lymph nodes or will have lead to hepatic metastases .
Some cases may come with symptoms that do not clearly classify them into one of the two previously mentioned categories; these include a wide variety of manifestations associated with pancreatic cancer and the syndrome is therefore described as mixed.
Some individuals with a somatostatinoma may also exhibit skin lesions characteristic of neurofibromatosis type 1 and symptoms further suggestive of a phaeochromocytoma, as these three medical entities are often concurrent   .
Upper Abdominal Pain
A 46-year-old woman with a history of recurrent mild upper abdominal pain and diarrhea for 10 months was admitted to our hospital. [ncbi.nlm.nih.gov]
Symptoms are non-specific but include upper abdominal pain, abdominal swelling and mass, jaundice, weight loss, nausea and vomiting [ 3 ]. Some patients will present with tumour burden from metastatic disease. [neupsykey.com]
These results suggest that somatostatin analogues may not influence tumor autonomy and that a SRIF response to food may contribute to early satiety in patients with somatostatinoma. [ncbi.nlm.nih.gov]
satiety, weight loss, malabsorptive diarrhea, gallstones Lung with liver metastasis 3097.8 61.1 14.0 (normal range, 36–179) Chemotherapy (cisplatin and vinblastine) Died of pneumonia and sepsis 22 F 47 Severe hyperglycemia and marked ketoacidosis, and [academic.oup.com]
Foul Smelling Stool
Steatorrhea or diarrhea episodes are common and individuals tend to report up to ten foul-smelling stools per day; achlorhydria or hypochlorhydria is a frequent finding but does not usually lead to any remarkable complaint. [symptoma.com]
Steatorrhea (very foul-smelling stool that floats). Gallstones. Yellowing of the skin and whites of the eyes. Weight loss for no known reason. Too much pancreatic polypeptide may cause: belly pain. an enlarged liver. [ronnyallan.com]
An initial screening colonoscopy 6 months prior to presentation identified a 5-cm rectal mass that biopsies confirmed as invasive adenocarcinoma. [acgcasereports.gi.org]
The patient initially refused other adjunctive exams but after 2 years she was admitted, presenting with itch, night sweats, severe fatigue, and unintentional weight loss. [ncbi.nlm.nih.gov]
Some individuals with a somatostatinoma may also exhibit skin lesions characteristic of neurofibromatosis type 1 and symptoms further suggestive of a phaeochromocytoma, as these three medical entities are often concurrent. [symptoma.com]
Diagnosing somatostatinomas requires a multitude of invasive and non-invasive tests. A complete blood count, biochemical profile and somatostatin serum levels (fasting) are the initial steps towards a successful diagnosis. Serum levels of this hormone that exceed 100 pg/ml are indicative of a tumor; patients tend to display a significant increase in these values.
A computerized tomography (CT) scan with intravenous contrast enhancement and magnetic resonance imaging (MRI) are the two radiologic modalities initially employed . They are considered of equal value when assessing the existence of a possible somatostatinoma, with the MRI being deemed superior to a CT scan only in the terms of skeletal and hepatic metastasis detection .
Endoscopic ultrasonography (EUS) can aid towards the diagnosis of a somatostatinoma accompanied by potential metastatic tumors in the lymph nodes; its contribution is limited in the illustration of distant metastasis. It also enables the evaluation of gastric pH to confirm hypochlorhydria. Finally, a fine needle aspiration (FNA), guided by ultrasonography, can be performed in order to cytologically analyze the lesion and confirm its type  .
Surgery would be the appropriate treatment in the early stage of the disease with good chances of cure. [ncbi.nlm.nih.gov]
Treatment [ edit ] Treatment is by chemotherapy with streptozocin, dacarbazine, doxorubicin or by 'watchful waiting' and surgical debulking via Whipple procedure and other resections of the gastrointestinal organs affected.  References [ edit ] External [en.wikipedia.org]
If diagnosed early in the absence of distant metastases the prognosis of papillary somatostatinoma with tumour resection is excellent. [ncbi.nlm.nih.gov]
prognosis compared to those with poor health Age of the individual: Older individuals generally have poorer prognosis than younger individuals Whether the tumor is occurring for the first time, or is a recurrent tumor. [dovemed.com]
Etiology Some SSomas are components of familial endocrine tumor syndromes. The cause of sporadic SSomas is not clear. [orpha.net]
Some somatostatinomas are associated with NF1, MEN1 and Von Hippel-Lindau syndromes; the etiology of their sporadic counterparts is unclear. [codes.iarc.fr]
(Etiology) The exact cause of Somatostatinoma development is unknown A majority of the tumors occur sporadically (about 95% of them), while the rest are inherited (familial Somatostatinoma) Research scientists believe that the cause of the condition is [dovemed.com]
In our previous study, 13 it was very difficult to differentiate the etiology of large subepithelial tumors, especially those larger than 9 cm in diameter, using only endosonographic characteristics. [e-ce.org]
The functioning and nonfunctioning tumor types are then fully discussed, covering epidemiology, diagnosis, morphology and prognosis of each entity. [books.google.com]
Somatostatinoma Pancreatic Somato - statinoma 2/3rds in head Duodenal somatostatinoma usually ampullary/ periampullary Get psamomma bodies Associated with Von Recklinghausenâ s disease; can rarely occur elsewhere Rarely associated with Somato - statinoma syndrome Epidemiology [gastroenterologybook.com]
Summary Epidemiology The estimated incidence is of 1/40,000,000. Approximately 80 cases of pancreatic SSoma have been reported to date but this is probably an underestimate. Clinical description SSomas usually range in size from 3-11cm. [orpha.net]
[…] scintigraphy Differential Diagnosis Diabetes mellitus (type 1 or 2) Cholecystitis Malabsorption syndromes Other neuroendocrine tumors – vasoactive intestinal polypeptide secreting tumor (VIPoma), carcinoid Gastroenteritis (chronic or relapsing) Background Epidemiology [arupconsult.com]
We also review the potential effects of somatostatin on glucose homeostasis and discuss the underlying pathophysiologic mechanisms. [ncbi.nlm.nih.gov]
Pathophysiology [ edit ] In a normal subject actions of somatostatin include: In the anterior pituitary gland, the effects of somatostatin are: Inhibit the release of growth hormone thus opposing the effects of growth hormone-releasing hormone (GHRH) [en.wikipedia.org]
1 Department of Endocrinology, School of Medicine with the Division of Dentistry, Medical University of Silesia, Katowice, Poland; 2 Department of Endocrinology, School of Medicine with the Division of Dentistry, Chair of Pathophysiology and Endocrinology [endocrine-abstracts.org]
However, owing to the proximity of the tumor to the ampulla of Vater, a sphincteroplasty was conducted to prevent potential obstruction. [jmedicalcasereports.biomedcentral.com]
Specialists note that 95% of somatostatinomas occur sporadically, therefore it is very difficult to foresee and prevent the disease. Symptoms of somatostatinoma The signs of this disorder depend on the size and the place of the tumor. [treatendocrine.com]
In cases where the tumor is located at a place where it cannot be resected then only chemotherapy is done to kill the cancer cells and prevent any further progression of the tumor. [epainassist.com]
Currently, there are no specific methods or guidelines to prevent Somatostatinoma. [dovemed.com]
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- Stelow EB, Woon C, Pambuccian SE, et al. Fine-needle aspiration cytology of pancreatic somatostatinoma: the importance of immunohistochemistry for the cytologic diagnosis of pancreatic endocrine neoplasms. Diagn Cytopathol. 2005 Aug;33(2):100-5.
- Mori Y, Sato N, Taniguchi R, et al. Pancreatic somatostatinoma diagnosed preoperatively: report of a case. JOP. 2014 Jan 10;15(1):66-71.