ABSTRACT
PURPOSE: This study was designed to review the clinical characteristics of gastrointestinal stromal tumors (GISTs) of the colon and rectum and to evaluate their immunohistochemical and pathologic features based on the current National Institutes of Health criteria. METHODS: Patient and disease characteristics, pathologic features, surgical or endoscopic management, and clinical outcomes of 11 patients with GISTs diagnosed and primarily treated at our institution between March 1995 and February 2009 were evaluated. RESULTS: Colorectal GISTs accounted for 4.4% of all GISTs. The primary location was the rectum (8 cases). Four patients had high-risk GISTs, 4 patients had low-risk GISTs, and 3 patients had very low-risk GISTs. All tumors were c-kit positive. Four patients underwent a radical resection, whereas 7 patients underwent an endoscopic resection (n=3) or a transanal excision (n=4). Two high-risk patients without adjuvant Imatinib mesylate therapy developed metastases, but the other high-risk patients with adjuvant Imatinib mesylate therapy didn't. CONCLUSION: Colorectal GISTs occurred predominantly in the rectum. Because GISTs do not metastasize through the lymphatics, small GISTs that are amenable to local excision or endoscopic resection can be treated by either of these techniques as long as negative microscopic margins are obtained around the primary tumor. Patients with high-risk GISTs should be considered for the use of Imatinib mesylate as adjuvant therapy.
Subject(s)
Humans , Benzamides , Colon , Gastrointestinal Stromal Tumors , Imatinib Mesylate , Mesylates , Neoplasm Metastasis , Piperazines , Pyrimidines , RectumABSTRACT
PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract. Recent studies have revealed much of the biological and genetics underpinning GISTs. METHODS: KIT, PDGFRA, NF2 and GPHN mutations were examined by PCR-SSCP and DNA sequencing. Immunohistochemical analyses of CD117, CD34, SMA, S-100 and desmin were performed in 11 GISTs cases, and each tumor classified as being either very low, low, intermediate or high risk. RESULTS: Mutation in exon 11 of KIT was identified in 6 of the 11 GISTs, but mutations in exon 9, 13 and 17 of KIT were not detected. Three cases lacking KIT mutations showed PDGFRA mutations. No NF2 mutations were detected. GPHN gene mutation in exon 1 was identified in one case, which showed a simple point mutation in exon 11 of KIT. In a correlation between the mutation types and risk of aggressive behavior, four tumors involved multiple ( >2 codons) KIT mutations and one showed a point mutation of KIT plus a GPHN mutation were high risk, but one tumor with a point mutation of KIT showed a low risk. Three tumors having a PDGFRA mutation were of intermediate or very low risk. CONCLUSION: Mutations at exon 9, 13 or 17 of KIT and a NF2 mutation are considered rare in sporadic GIST. KIT and PDGFRA mutations appeared to be alternatives. A GPHN mutation occurring with a KIT mutation may be a secondary change in the pathogenesis of GIST, as the KIT mutation is a major event in GIST. KIT mutant GIST may have a poorer prognosis than PDGFRA mutant GIST.
Subject(s)
Desmin , Exons , Gastrointestinal Stromal Tumors , Gastrointestinal Tract , Genetics , Point Mutation , Prognosis , Sequence Analysis, DNAABSTRACT
PURPOSE: Gastrointestinal stromal tumors (GIST) are a heterogenous group of mesenchymal neoplasms of the gastrointestinal tract. This study was performed to determine the clinical characteristics and prognostic factors of GIST. METHODS: We studied 24 cases of GIST collected over a 9 year period. This retrospective review analyzed the clinical presentation, pathologic examination, and long-term follow-up of patients with GIST. The clinicopathological features were evaluated to identify the predictors of survival. RESULTS: The most common clinical presentation was pain or discomfort (37.5%). GISTs were found to be typically present in older individuals and be most common in the stomach (41.7%). All patients underwent surgical resection with curative intent. The follow-up period ranged from 3 to 110 months. Recurrence occurred in 11 (45.8%) of 24 patients. According to multivariate analysis, survival was inversely correlated with size (P=0.032) and the number of mitoses (P=0.030). Patients younger than 50 had an independent value for prognostic prediction (P=0.058). CONCLUSION: Tumor size, mitotic index and patient's age can be used as prognostic factors for GIST according to the results of our study. But, better pathological and immunohistochemical methods are still required to improve GIST prognosis.