Over the last decade, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure gastrointestinal mesenchymal tumors to well-defined tumors with distinctive clinical, morphologic, ultrastructural, histogenetic, and molecular characteristics, for which targeted therapy is available. This is largely attributable to the discovery of CD117 overexpression and activating mutations in c-kit or platelet-derived growth factor alpha genes in most of GISTs. The availability of specific diagnostic tests and targeted therapy for GISTs has led to an increased awareness of these tumors. At the same time, the list of potential GIST mimics has lengthened considerably and it has become increasingly important that GISTs be distinguished from their mimics because correct diagnosis has implications for both treatment and prognosis. The purpose of this review is to provide an update of the expanding differential diagnosis of GISTS, to draw attention to unusual GIST variants, to provide a practical approach the differential diagnosis of GISTs and to highlight some of the challenges faced by pathologists in resolving this differential diagnosis.

Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis.

Gastrointestinal stromal tumor and gastric adenocarcinoma collision tumors

Gastritis and Gastropathies

/pdf/gastric-carcinogenesis-by-duodenal-reflux-through-gut-2wo14yhw5z.pdf

Gastric carcinogenesis by duodenal reflux through gut regenerative cell lineage

Gastric adenocarcinoma appearance in leiomyoma: A case report.

A case of gastrointestinal stromal tumor (GIST) with an unusual glandular component is reported. The tumor was found in the gastric fundus of a 93-year-old woman. Histologically, the lesion showed a biphasic adenosarcoma-like structure. Typical low-grade spindle cell patterns of GIST were intermingled with numerous and partly cystic glands. The glandular epithelium had pyloric/foveolar-like appearance, with foci of intestinal metaplasia and low-grade dysplasia. The stromal component was immunoreactive for CD117 (c-kit) and CD34, and negative for myoid and neuroid markers. The ultrastructural examination found nondescript and undifferentiated spindle cells. The gastric mucosa and submucosa near the tumor contained a small area with features of gastritis cystica profunda, with glands similar to those present inside the tumor. Therefore, a collision of GIST and gastritis cystica profunda is suggested in the histogenesis of the lesion.

/pdf/gastrointestinal-stromal-tumor-gist-with-glandular-component-4tydfz97io.pdf

A Chlumská

Papers

Gastrointestinal stromal tumor (GIST) with glandular component. A report of an unusual tumor resembling adenosarcoma