Neuroendocrine tumors, such as carcinoid tumors, overexpress somatostatin receptors in their membranes. Octreotide is an analogue whose molecule is a shortened version of somatostatin's with a high affinity for these receptors. The labelled form of octreotide is able to be imaged in scans (Octreoscan) and, therefore, pathological conditions overexpressing somatostatin receptors are easily recognized in this technique. Specifically, in the case of the detection of carcinoid tumors, the Octreoscan has sensitivity nearly to 90%.
A research article to be published on September 14, 2008 in the World Journal of Gastroenterology addresses this question. The research team led by Alberto Fernandez from POVISA Hospital in Spain presents a case of a patient with a high suspicious of ileal carcinoid tumor (according to CT-scan and colonoscopy results) with a positive Octreoscan, showing uptake in the same bowel reported as pathological in CT. The patient underwent surgery and histological analysis reported Crohn's disease.
This article is the second report of CD a cause of false positive in octeotride scan. In order to explain this abnormal uptake, immunohistochemical studies were performed but the authors did not find somatostatine receptors in the sample. In the previous report published of CD mimicking an ileal carcinoid there is no evidence that somatostatin receptors were determined.
The authors did not find any explanation, and concluded encouraging physicians to be aware of CD as a cause of false positive results of Octreoscan and that further studies should be made in order to assess the possible causes of this abnormal uptake.
Reference: Fernandez A, Tabuenca O, Peteiro A. A "false positive" octreoscan in ileal Crohn's disease. World J Gastroenterol 2008; 14(34): 5349-5352
http://www.wjgnet.com/1007-9327/14/5349.asp
Correspondence to: Alberto Fernandez, Servicio de Aparato Digestivo, Hospital POVISA, c/ Salamanca 5, Vigo (Pontevedra) 36211, Spain. afvillaverde@gmail.com
Telephone: +34-98-6413144 Fax: +34-98-6421439
About World Journal of Gastroenterology
World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H pylori infection. It provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2003-2000 IF: 3.318, 2.532, 1.445 and 0.993. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th of every month. The WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the title China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.
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World Journal of Gastroenterology