Pathology of Gastrointestinal Stromal Tumors

Department of Pathology, Medical University of Graz, Auenbruggerplatz 25, A 8036 Graz, Austria.
Hematology/oncology clinics of North America (Impact Factor: 2.3). 03/2009; 23(1):49-68, vii-viii. DOI: 10.1016/j.hoc.2008.12.002
Source: PubMed


Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The vast majority of GISTs harbor a KIT or PDGFRA mutation and express KIT by immunohistochemistry. However, KIT-negative tumors and tumors showing unusual morphologic features can cause major diagnostic problems. The ability to inhibit the active KIT or PDGFRA kinase with tyrosine kinase inhibitors and alternative drugs demands more than ever accurate tumor classification and risk assessment. This article focuses on the pathology of GIST, including unusual variants and morphologic changes resulting from treatment. Parameters for risk assessment, potentially helpful new immunohistochemical markers, differential diagnosis, and the application of molecular classification schemes are discussed.

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    • "A GIST can be located anywhere in the gastrointestinal tract, the most common sites being the stomach (63%), followed by small intestine (23%), colorectal (5%), and esophagus (1.6%) [4]. Histologically, they are mesenchymal spindle cells and immunohistochemically positive for tyrosine kinase receptor CD 117 (c-KIT), related tyrosine kinase receptor PDGFR (platelet-derived growth factor receptor α, a KIT), and CD34 expression [5]. KIT has been demonstrated as a very specific and sensitive marker to mesenchymal tumors in the GI tract and around 95% of GISTs express KIT. "
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    ABSTRACT: Introduction. Gastrointestinal stromal tumor (GIST) in the ileum is an extremely rare cause of recurrent lower gastrointestinal bleeding (GIB). Case Report. An 89-year-old man was admitted with melana. He had extensive PMH of CAD post-CABG/AICD, AAA repair, chronic anemia, myelodysplastic syndrome, lung cancer after resection, and recurrent GIB. Prior EGDs, colonoscopies, and upper device-assisted enteroscopy showed duodenal ulcer, A-V malformation s/p cauterization, and angioectasia. On admission, Hb was 6.0 g/dL. An endoscopic capsule study showed an ulcerated tumor in the ileum. CT showed no distant metastasis. The lesion was resected successfully and confirmed as a high-grade GIST. The patient was discharged with no further bleeding. Discussion. Early diagnosis for patients with ileal GIST is often challenging. Video capsule endoscopy and double balloon enteroscopy could be useful diagnostic tools. Surgical removal is the first line for a resectable GIST. Imatinib has become the standard therapy. Conclusion. This is a unique case of an ileal GIST in a patient with recurrent GIB which was diagnosed by video capsule. Complicated medical comorbidities often lead to a significant delay in diagnosis. Therefore, we recommend that if GIB does not resolve after appropriate treatments for known causes, the alternative diagnosis for occult GIB must be considered, including malignancy such as GIST.
    Full-text · Article · Aug 2013
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    • "Approximately ~95% of cases are positive for c-kit protein (Figs. 1, 2). c-kit negative GISTs account for ~5% of cases and can cause diagnostic difficulties, but given the rather limited choice in mesenchymal diagnostic considerations at these sites, they can often be diagnosed by excluding other potential mimics by immunohistochemical characterization (14). c-kit staining with polyclonal anti-c-kit antibody is mandatory for diagnosis. "
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    ABSTRACT: Despite the rarity in incidence and prevalence, gastrointestinal stromal tumor (GIST) has emerged as a distinct pathogenetic entity. And the clinical management of GIST has been evolving very rapidly due to the recent recognition of its oncogenic signal transduction pathway and the introduction of new molecular-targeted therapy. Successful management of GIST requires a multidisciplinary approach firmly based on accurate histopathologic diagnosis. However, there was no standardized guideline for the management of Korean GIST patients. In 2007, the Korean GIST study group (KGSG) published the first guideline for optimal diagnosis and treatment of GIST in Korea. As the second version of the guideline, we herein have updated recent clinical recommendations and reflected changes in diagnosis, surgical and medical treatments for more optimal clinical practice for GIST in Korea. We hope the guideline can be of help in enhancing the quality of diagnosis by members of the Korean associate of physicians involving in GIST patients's care and subsequently in achieving optimal efficacy of treatment.
    Full-text · Article · Nov 2010 · Journal of Korean medical science
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    ABSTRACT: Objective The purpose of this study was to search the ultrasound features of small intestinal stromal tumor (SIST) in women by reviewing their clinical data. Methods The study group consisted of 18 female patients with pathologically proven SIST in our hospital from 2000 to 2009. Medical records were reviewed for clinical information such as manifestation, findings of ultrasonography and immunohistochemical phenotype. Results The average age of 18 female patients with SIST was 55.2 years (ranged, 39–84 years). Seventeen cases of them had abnormal hypogastric masses, no mass in one case. The shapes of masses were round or lobulate beside tightly uterus or ovary. The echo of masses was low. It’s borders were clear and sometimes irregular. The sizes of the masses varied from 6.89–193.05 cm3, the diameter ranged from 24 mm–110 mm, 85.3% of which 50 mm–110 mm. There were rare color flow signals under color Doppler velocity mode or color Doppler power mode. Exploratory laparotomy confirmed that 16 cases of the tumors originated from small intestine, and 2 cases from the ileocecal. The positive rate of the immunohistochemical phenotype of CD117 was 88.2%, and CD34 was 76.5%. The examination of pathology confirmed that 16 cases were malignant and 2 cases borderline tumors. Eighteen cases underwent radical surgical resection. Conclusion The characteristics of SISTs in women pelvic cavity are: age > 40 years, a mass (proven not from productive system by ultrasonography) in pelvic cavity, melena, positive findings in pathology and CD117/CD34, especially notice masses which diameter is more than 50 mm and possess potential malignant. Ultrasonography is a convenient and effective tool of screening SISTs.
    No preview · Article · Dec 2010 · The Chinese-German Journal of Clinical Oncology
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