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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neoplasms of the colonic submucosa are rare in children. Gastrointestinal stromal tumors (GISTs) are undifferentiated tumors, usually diagnosed by immunohistochemistry. We report a 4-year-old girl with a submucosal GIST of the ascending colon, which was detected by computed tomography. Diagnosis after ileocecal resection was established by histology. In addition, sections were examined immunohistochemically, using antibodies against vimentin, desmin, alpha-smooth muscle actin, S100, neuron-specific enolase, c-kit, and CD34. Hematoxylin and eosin-stained sections showed interlacing fascicles with occasional palisades of epithelioid and spindle cells. The tumor cells were positive for vimentin and CD34. To our knowledge, this is the first reported case of colonic stromal tumor in a child.
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PMID:Clinical and histopathological features of colonic stromal tumor in a child. 1086 54

Gastrointestinal autonomic nerve (GAN) tumor is a relatively newly defined member of the gastrointestinal stromal tumor family, which is a rare group of mesenchymal neoplasms originating in the bowel wall throughout the entire gastrointestinal tract. A thorough search of the literature revealed only one brief mention of this tumor arising in the rectum. We present a full description of such a tumor and summarize the clinical characteristics, therapeutic measures used, biological behavior, and outcome of this unique case.
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PMID:Gastrointestinal autonomic nerve (GAN) tumor of the rectum. 1087 77

Germline mutations in one of two alleles of c-ret, c-met and c-kit protooncogenes have been revealed to be the causes of three autosomal dominant hereditary tumors; multiple endocrine neoplasia type 2(MEN2), hereditary papillary renal cell carcinoma (HPRCC), and familial gastrointestinal stromal tumor(FGIST), respectively. Patients with MEN2A have missense mutations at extracellular cysteine rich domain of c-ret, those with MEN2B have missense mutations at tyrosine kinase domain of c-ret, those with HPRCC have missense mutations at tyrosine kinase domain of c-met, and those with FGIST have in-frame deletion mutations at juxtamembrane domain of c-kit. All of these mutations are assumed to cause constitutive activation of protooncogenes without binding to ligands, resulting in tumor formation.
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PMID:[Mechanism of carcinogenesis by germline mutation of protooncogene in hereditary tumors]. 1087 45

Intra-abdominal fibromatosis (IAF) is an uncommon benign neoplasm that usually occurs in the mesentery or retroperitoneum and may, on occasion, mimic a gastrointestinal stromal tumor (GIST). Differentiating between these two entities is important clinically because IAF is a benign tumor whereas GISTs frequently have malignant potential. In this study, the authors identified 13 cases of IAF with prominent involvement of the bowel wall as well as 35 GISTs of the small intestine, colon, or mesentery and analyzed their clinical, gross, histologic, immunophenotypic, and ultrastructural characteristics to identify important distinguishing features. Patients with IAF were younger (mean, 34 yrs) than patients with GIST (mean, 54 yrs). Both types of tumors tended to be large, but GISTs were soft and lobulated with hemorrhage, necrosis, or cystification whereas IAFs were firm, tan, and homogeneous. Histologic features characteristic of GIST included the presence of spindle or epithelioid cells with variable architecture, mitotic activity (range, <1-95 mitoses/50 high-power fields [hpf]; mean, 15 mitoses/50 hpf), nuclear atypia, and myxoid or hyalinized stroma. Necrosis and hemorrhage were seen in 16 and 25 tumors, respectively. In contrast, IAFs were composed of broad, sweeping fascicles of monotonous spindle cells with mitotic activity (range, <3-11 mitoses/50 hpf; mean, 4 mitoses/50 hpf), bland nuclear features, and finely collagenous stroma. Necrosis, hemorrhage, and myxoid degeneration were not seen. Immunohistochemical studies performed on a limited number of GISTs and IAFs demonstrated that cells expressed vimentin (100% GIST and IAF), CD117 (88% GIST and 75% IAF), CD34 (42% GIST and 0% IAF), smooth muscle actin (63% GIST and 75% IAF), muscle actin (75% GIST and 75% IAF), desmin (8% GIST and 50% IAF), and S-100 protein (16% GIST and 0% IAF). Ultrastructural analysis of 21 GISTs revealed incomplete smooth muscle differentiation in some tumors whereas IAFs were shown to have complete myofibroblastic/fibroblastic differentiation. Information regarding clinical outcome was available on 29 patients and revealed that three patients with histologically benign GISTs were alive with no evidence of disease at 5 months to 6 years (mean, 3.5 yrs) and one patient with a histologically benign tumor died of disease after 7 years. Of patients with histologically malignant GIST, one died of surgical complications, 10 were alive without disease at I to 13 years (mean, 5.4 yrs), four were alive with disease at 4 months to 15 years (mean, 3.8 yrs), three had disseminated disease at operation, and seven were dead of disease at 10 months to 3 years (mean, 2.2 yrs). Follow up of eight patients with IAF demonstrated that five were alive without disease at 4 months to 15 years (mean, 5.3 yrs) and three had recurrences at 1 (two patients) and 2 years (one patient). In summary, IAFs can have many features (large size, infiltration of adjacent structures, mitotic activity) that can cause diagnostic confusion with GISTs and, importantly, the degree of mitotic activity present in IAFs may overlap that seen in malignant GISTs. These entities can be distinguished primarily by their light microscopic and ultrastructural features but there is a notable overlap in their immunohistochemical profiles. The distinction between these neoplasms is important because there are important clinical implications for the patient.
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PMID:Gastrointestinal stromal tumor versus intra-abdominal fibromatosis of the bowel wall: a clinically important differential diagnosis. 1125 38

To identify genetic changes related to tumor progression and find out diagnostic and prognostic genetic markers in gastrointestinal stromal tumors (GISTs), 95 tumor samples (24 benign GISTs, 36 malignant primary GISTs, and 35 GIST-metastases) from 60 patients were studied using comparative genomic hybridization. DNA copy number changes were detected in all samples. Benign GISTs had a mean of 2.6 aberrations/ sample (losses:gains, 5:1) and significantly fewer DNA copy number changes and fewer gains than malignant primary and metastatic GISTs (P < 0.01). High-level amplifications were not seen in benign GISTs. Malignant primary GISTs had a mean of 7.5 aberrations/tumor (losses: gains, 1.6:1), whereas the mean number of aberrations/metastatic GIST was 9 (losses:gains, 1.8:1). Frequent changes observed in all GIST groups included losses in chromosome arms 1p (51%), 14q (74%), and 22q (53%). Gains and high-level amplifications at 8q and 17q were significantly more frequent in metastatic GISTs (57 and 43%) than in benign GISTs (8 and 0%; P < 0.001) and malignant primary GISTs (33 and 25%; P < 0.05). Gains and high-level amplifications at 20q were only seen in malignant primary and metastatic GISTs (P < 0.01), and gains at 5p were not detected in benign GISTs (P < 0.01). Losses in chromosome arm 9p were never seen in benign tumors (P < 0.001), and they were more frequent in metastatic GISTs than in malignant primary GISTs (63 and 36%; P < 0.05). Losses in 13q were less frequent in benign GISTs than in malignant primary (P < 0.05) and metastatic (P < 0.01) GISTs. Our results show that several DNA copy number changes are related to the behavior of GISTs and can be used as prognostic markers for tumor progression.
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PMID:DNA sequence copy number changes in gastrointestinal stromal tumors: tumor progression and prognostic significance. 1091 66

Gastrointestinal stromal tumors (GISTs), also referred to as "gastrointestinal pacemaker cell tumors (GIPACT)" are mesenchymal neoplasms that are phenotypically similar to the interstitial cells of Cajal (ICC). Cytogenetic studies of this entity are rare and molecular cytogenetic studies utilizing chromosome-specific probes are nonexistent. In the current study, cytogenetic and molecular cytogenetic analysis of 12 histologically and immunohistochemically confirmed GISTs revealed loss of a whole chromosome 14 or region(s) of 14q in 8 tumors evaluated (67%) and loss of a whole chromosome 22 or region(s) of 22q in 8 (67%) patients. Loss of 14q and 22q were observed in histologically benign and malignant GISTs. Structural rearrangements of chromosome 1 were observed in 2 malignant GISTs. These findings indicate that loss of 14q and 22q are nonrandom, early events in GIST tumorigenesis and suggest that tumor suppressor genes responsible for the development of this neoplasm may be located on these chromosomal arms.
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PMID:Loss of 14q and 22q in gastrointestinal stromal tumors (pacemaker cell tumors). 1094

Gastrointestinal stromal tumors (GISTs) comprise a heterogeneous group of neoplasms of the gastrointestinal tract previously referred to as leiomyomas, leiomyosarcomas, or schwannomas. GISTs derive from the interstitial cell of Cajal and, in addition to variable expression of smooth muscle and neural markers, they characteristically express CD34 and CD117. To our knowledge, the cytologic appearance of gastric neoplasms designated as GISTs has never been reported. We illustrate the fine-needle aspiration (FNA) cytology findings of a gastric stromal tumor having spindle cells with delicate cytoplasm and prominent nuclear palisading. Consistent core biopsy and immunochemistry findings further supported the diagnosis of GIST. Pathologic evaluation of the resected tumor confirmed the cytologic diagnosis. In the appropriate clinical and radiologic setting, a confident diagnosis of GIST can be established by FNA cytology and core biopsy. The roles of immunochemical stains and other ancillary techniques in reaching the correct diagnosis are addressed.
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PMID:Cytomorphology of gastrointestinal stromal tumor: diagnostic role of aspiration cytology, core biopsy, and immunochemistry. 1094 1

Fine-needle aspiration biopsy is a reliable and accurate method for the endoscopic diagnosis of gastrointestinal malignancies and it is particularly well suited for evaluation of submucosal lesions. We report the cytopathologic findings of a case of malignant carcinoid tumor of a 44-year-old male who presented with melena and a nonhealing duodenal ulcer. Endoscopic ultrasound examination revealed a submucosal lesion in the pyloric region. Fine-needle aspiration revealed abundant cellularity with tumor cells arranged in sheets and loose groups and dispersed single cells in a clean background. Papillary fragments, capillaries cuffed by tumor cells, and rosette formation were also noted. The cells were moderate in size, round to oval, with a small subpopulation of spindle-shaped cells. The nuclei were uniform, round to oval, with smooth nuclear borders. The chromatin pattern was finely granular with a salt-and-pepper appearance. The cytoplasm of the cells was small to moderate in amount, pale, and showed fine granularity. The differential diagnosis included a neuroendocrine neoplasm vs. an epithelioid gastrointestinal stromal tumor. The tumor cells were focally positive for chromogranin and negative for CD34, supporting the diagnosis of a neuroendocrine neoplasm. The differential diagnosis of primary gastrointestinal carcinoid tumors from gastrointestinal stromal tumors can be very difficult in cytologic material. In cases when diagnostic material is scant, or only present on one smear, the use of smear division and cell transfer in order to perform immunocytochemical stains may be of considerable value to confirm the neuroendocrine nature of the neoplasms.
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PMID:Duodenal carcinoid tumor: report of a case diagnosed by endoscopic ultrasound-guided fine-needle aspiration biopsy with immunocytochemical correlation. 1094 6

Tumors of the small intestine are relatively rare. The diagnosis is difficult to establish because the symptoms are vague and non-specific. Although the small intestine constitutes 75% of the length and over 90% of the mucosal surface area of the gastrointestinal tract, only 1 to 2% of gastrointestinal malignancies occur in this segment. Metastases are usually present at the time of diagnosis. The outcome of these patients can be improved if the possibility of a malignant small bowel tumor is considered in all cases of unexplained abdominal pain or gastrointestinal bleeding, especially in younger age. Malignant tumors occur with increasing frequency in distal small bowel with a preponderance of malignant lesions in the ileum compared with the jejunum and the duodenum. Adenocarcinoma is the most common tumor of the primary malignant small bowel tumors, followed by carcinoid, lymphoma and leiomyosarcoma. Mesenchymal tumors of the gastrointestinal tract, traditionally regarded as smooth muscle tumors, have demonstrated different cellular differentiations based on immunohistochemical and ultrastructural features. Therefore the terms leiomyoma and leiomyosarcoma have been replaced by a more encompassing term, gastrointestinal stromal tumor (GIST). The majority of GISTs occurs in the stomach; stromal tumors involving the small intestine (SISTs) are far less common but seem to have greater malignant potential. The clinical a case of a small intestinal stromal tumor (SIST), localised in the jejunum and characterised by an uncertain histological aspect, is presented and a review of the literature is made.
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PMID:[Gastrointestinal stromal tumors. A case of small intestine stromal tumor (SIST) with an uncertain biological aspect]. 1095 71

The authors describe a patient with a bleeding gastrointestinal stromal tumor of the stomach who was treated successfully by laparoscopic proximal gastrectomy with jejunal interposition. Immunohistochemically, the tumor was positive for vimentin and CD34 and was diagnosed as a gastrointestinal stromal tumor of low-grade malignancy. Because it is difficult to diagnose this disease preoperatively and a malignant phenotype has been reported, resulting in liver metastasis and peritoneal dissemination, it is desirable to treat this disease with as little manipulation as possible. To achieve this, laparoscopic surgery is a feasible option for the treatment of gastrointestinal stromal tumors.
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PMID:Gastrointestinal stromal tumor of the stomach successfully treated by laparoscopic proximal gastrectomy with jejunal interposition. 1096 54


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