BACKGROUND Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. More rarely neoplasms with histology and immunohistochemistry similar to GISTs may occur outside the gastrointestinal tract ( omentum, mesentery and retroperitoneum) and are so-called Extra-gastrointestinal Stromal Tumors (EGISTs). EGISTs arising in the retroperitoneum are...

although the majority of mesenchymal lesions of the gastrointestinal tract are neoplastic in nature, but nonneoplastic reactive processes may also involve the gastrointestinal tract and mesentery. some more aggressive neoplasms located in same area, such as fibromatosis or gastrointestinal stromal  tumors  may  be  cause  of  diagnostic  confusion.  reactive  nodular  fibrous  pseudo  tumor (rn...

Objectives CD200 expression has been well studied in hematopoietic malignancies; however, CD200 expression has not been well-characterized in neuroendocrine neoplasms. We examined CD200 expression in 391 neuroendocrine neoplasms from various anatomic sites. Methods Tissue blocks containing pulmonary small cell carcinoma, pulmonary carcinoid, large cell neuroendocrine carcinoma, pancreatic neu...

Carcinoid tumour accounts for one per cent of all gastrointestinal neoplasms and has been reported in 0.5% of appendicectomy specimens. Local gastrointestinal complications occur infrequently and we report a case of repeated and massive gastrointestinal haemorrhage from a non-metabolically active carcinoid tumour of the distal ileum diagnosed by colonoscopy.

Gastrointestinal stromal tumors (GISTs) are relatively rare neoplasms of the gastrointestinal tract originating from the pluripotential mesenchymal stem cells, which differentiate into interstitial Cajal cells. They are usually located in the upper gastrointestinal track. These tumors are typically defined by the expression of c-KIT (CD117) and CD34 proteins in the tumor cells. A small percenta...

Gastrointestinal stromal tumors (GIST) are uncommon mesenchymal spindle-cell or epithelioid neoplasms, located mainly with higher frequency in the stomach and small bowel. GISTs represent the majority of primary non-epithelial neoplasms of the digestive tract, most frequently expressing the KIT protein a transmembrane tyrosine kinase receptor for stem cell factor. Extra-gastrointestinal stromal...

Gastrointestinal stromal tumors are a heterogeneous group of mesenchymal neoplasms of the gastrointestinal tract in which routine histopathological evaluation fails to reveal definitive evidence of differentiation. Given the heterogeneity in clinical presentation and the frequent morphological overlap, the biological behavior of these neoplasms is difficult to predict. We have evaluated, by Cox...

BACKGROUND Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are complex tumors whose incidence is rising and whose treatment requires precise classification and risk stratification. METHOD Selective review of the relevant literature, including recently published guidelines. RESULTS GEP-NENs are initially classified by their degree of histological differentiation and their graded c...