1/32. Malignant gastrointestinal stromal tumor of the ampulla of vater: a case report.GIST is a rare neoplasm, the majority of GISTs are located in the stomach and small intestine. Most GISTs are diagnosed histopathologically after resection because of submucosal location. A 37-year-old female patient presented with a 2-weeks history of generalized weakness, nausea accompanied by intermittent passage of black, tarry stools. Esophagogastroduodenoscopy and ERCP showed a large round mass measuring 5 cm in diameter in the ampulla of vater with ulcer crack. Endoscopic multiple biopsies from the mass including ulcer base were taken. light microscopic findings showed spindle-shaped and epitheloid tumor cells having high cellularity and frequent mitotic figures. On immunohistochemical stainings, the tumor cells were positive for CD34 and smooth muscle actin. Based on these preoperative findings, a diagnosis of malignant GIST of the ampulla of vater was made probably. After operation, immunohistochemical studies revealed positive reaction for c-kit and vimentin, as well as focally reactive for CD34 and smooth muscle actin. We report a case of GIST in the ampulla of vater presenting with melena that was diagnosed preoperatively and postoperatively.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
2/32. Immunohistopathological and molecular genetic features of a case in which gastrointestinal stromal tumor recurred five times.Gastrointestinal stromal tumor (GIST) is a distinct group of mesenchymal neoplasms recently shown to exhibit differentiation toward interstitial cells of Cajal. Although previous studies have shown that the clinical outcome of patients with GIST is associated with mitotic activity, the proliferation index determined by the Ki-67 labeling index, immunophenotype (CD34 and/or p53) and mutation in exon 11 of the c-kit, a definitive discrimination between benign and malignant GIST has not yet been established. We report a patient in whom malignant GIST in the abdomen recurred five times. In this case, the primary GIST and the five recurrent GIST were associated with c-kit immunoreactivity, but the mitotic index of the GIST tended to be increasingly higher with subsequent recurrences. Mutational analysis of the c-kit revealed that the primary and recurrent GIST were mutant-negative. These data indicated that 'morphologically appearing benign' tumors with lower proliferative parameters may also have the capacity of metastasis and recurrence.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
3/32. Gastrointestinal stromal tumor of the retroperitoneum: CT and MR findings.Gastrointestinal stromal tumor (GIST) is a non-epithelial neoplasm arising from the wall of the gastrointestinal (GI) tract. Although the majority of GISTs are located in the GI tract, some GISTs occur in the omentum, mesentery and retroperitoneum. GIST arising in the retroperitoneum is extremely rare, and its radiological findings have not been well described. We report a case of primary retroperitoneal GIST and discuss its imaging findings.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
4/32. Gastrointestinal stromal tumor of the stomach with rhabdoid phenotype: immunohistochemical, ultrastructural, and immunoelectron microscopic evaluation.A variety of neoplasms with rhabdoid differentiation have been reported in many sites. The authors describe a case of gastrointestinal stromal tumor (GIST) of the stomach that exhibited prominent rhabdoid features. Immunohistochemically, the tumor cells displayed positive staining for vimentin, c-kit, CD34, and alpha smooth muscle actin. Ultrastructural examination of the rhabdoid tumor cells revealed paranuclear whorls of intermediate filaments, which were immunoreactive for vimentin by both light microscopic immunohistochemical and protein A gold immunoelectron microscopic techniques. On H&E light microscopic examination alone, such a tumor could be mistaken for a variety of epithelial, mesenchymal, or other neoplasms that may show rhabdoid features. One report of GIST with a rhabdoid histologic phenotype has been described. This is the second known report of such a case with immunophenotypic and ultrastructural evaluation, and the first case with immunoelectron microscopic examination.- - - - - - - - - - ranking = 2keywords = neoplasm (Clic here for more details about this article) |
5/32. Gastrointestinal stromal tumor presenting as a recurrent vaginal mass.gastrointestinal stromal tumors are CD117 (c-Kit)-positive mesenchymal neoplasms with histologic and ultrastructural features of the interstitial cell of Cajal. While tumors outside of the gastrointestinal tract have been described, to our knowledge the case we present is the first such case in the vagina. We describe a 75-year-old woman with a recurrent vaginal gastrointestinal stromal tumor without apparent rectal involvement. This tumor was characterized by short intersecting fascicles of spindled cells, focal necrosis, and 12 to 15 mitoses per 50 high-power fields. immunohistochemistry revealed diffuse cytoplasmic positivity for CD117 (c-Kit), CD34, vimentin, and h-caldesmon. Tumor cells were negative for S100, desmin, actin, and CAM 5.2. The differential diagnosis in this case included a vaginal smooth muscle tumor. While histologically similar to a smooth muscle neoplasm, the immunohistochemical profile ruled out smooth muscle differentiation. Gastrointestinal stromal tumor should be considered in the differential diagnosis of vaginal mesenchymal neoplasms.- - - - - - - - - - ranking = 3keywords = neoplasm (Clic here for more details about this article) |
6/32. Imatinib in gastrointestinal stromal tumors.gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasms of gastrointestinal tract. The tumors express the cell surface transmembrane receptor KIT that has a tyrosine kinase activity and is a protein product of KIT protoeoncogene. These tumors occur in the whole of gastrointestinal tract. Treatment includes surgical resection for localized tumors. For metastatic disease treatment options include systemic chemotherapy, radiation therapy, with a response rate of less than 10%. Presently Imatinib; a tyrosine kinase inhibitor has shown promising result with response rates upto 59-69% in phase II results in metastatic setting; and ongoing phase II & phase III trials in adjuvant setting will help to establish its role as an adjuvant to surgery. We have treated eleven patients of metastatic GIST with Imatinib and we hereby present these cases.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
7/32. bronchogenic cyst of the stomach masquerading as benign stromal tumor.Gastric bronchogenic cyst is an extremely rare lesion. A 62-year-old Korean woman presented with an incidentally found perigastric nodule. An abdominal ultrasonogram and computed tomography showed a 1.5 cm solid, homogeneous, low-density nodule in the hepatogastric ligament near the gastric lesser curvature. At the time of surgery, a soft 1.7 cm nodule was found in the lesser curvature side just below the gastroesophageal junction, and a gelatinous mass was protruded from the nodule during the resection. Microscopically, the gastric subserosa showed cystic structures lined by pseudostratified ciliated columnar epithelium, seromucinous gland, connective tissue and complete layers of smooth muscle bundles. Neither cartilage nor gastrointestinal epithelium was identified. A mucocele was found near the cyst and foamy cells and faintly bluish mucinous substances were found near the cystic structures. All the mucinous substances were stained by alcian blue at pH 2.5 with varying degrees of staining intensity. The present case is the smallest reported cyst among the gastric bronchogenic cysts, and these lesions are unusually located at the lesser curvature side of the stomach. Although these lesions are very rare, gastric bronchogenic cyst should be included in the differential diagnosis of gastric wall mass.- - - - - - - - - - ranking = 0.0067240889132785keywords = soft (Clic here for more details about this article) |
8/32. Primitive mesenteric gastrointestinal stromal tumor with autonomic nerve/ganglionic differentiation presenting as a huge mass with small synchronous nodules.We present a case of a primary mesenteric ectopic gastrointestinal stromal tumor. The pathologic characteristics of this neoplasm, autonomic nerve/ganglionic differentiation and presentation as a huge mass with small synchronous nodules, have not been previously described in the literature.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
9/32. Esophageal GIST: therapeutic implications of an uncommon presentation of a rare tumor.gastrointestinal stromal tumors (GISTs) are rarely reported in the esophagus. The authors report a patient with an esophageal GIST, incidentally found after an echocardiogram. CT scan and endoscopic ultrasonography showed the tumor in the dependence of the muscularis propria of the esophageal wall. An Ivor-Lewis esophagectomy was performed. The tumor was well-circumscribed involving the submucosal and the muscular layers of the esophagus, measuring 13.5 x 8.5 x 7.6 cm, without involving the surgical margins. Histologically, the tumor consisted of spindle cells, with low mitotic index (2/50 HPF), that were immunoreactive for KIT (CD117) and CD34, consistent with GIST of high risk of aggressive behavior. No adjuvant therapy was given to the patient, who is alive and without evidence of disease 1 year after surgery. Since esophageal GISTs are rarely reported in the literature and usually have a poor prognosis, the diagnostic differentiation of these tumors from other more common mesenchymal neoplasms is essential, both for therapeutic and prognostic reasons.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
10/32. A case of gastrointestinal stromal tumour of the ampulla of vater.Gastrointestinal stromal tumour rarely develops in the duodenal ampulla region. We report here a case of gastrointestinal stromal tumour of the ampulla of vater found in a 44-year-old Japanese man presenting with biliary obstruction. He died of hepatic failure with diffuse liver metastasis. The postmortem examination showed a large Borrman type III-like tumour in the duodenal ampullary region with direct invasion of the pancreas and extrahepatic bile duct as well as metastases to the liver and regional lymph nodes. The duct orifice was located at the centre of the tumour. Microscopically, the tumour consisted of anaplastic spindle cells with high mitotic activity (90 mitoses per 50 high-power fields). Immunohistochemically, the spindle cells were positive for KIT and CD34. The final diagnosis was high-grade malignant gastrointestinal stromal tumour of the ampulla of vater. Considering the recent advances in the diagnosis and treatment of gastrointestinal stromal tumour, this neoplasm should be included in the differential diagnosis of the tumours appearing in the duodenal ampulla region.- - - - - - - - - - ranking = 1keywords = neoplasm (Clic here for more details about this article) |
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