| Abstract|| |
Gastrointestinal stromal tumors (GISTs) are rare and account for 0.1% -0.3% of all gastrointestinal neoplasms and 5.7% of sarcomas. GISTs were classified as smooth muscle tumors, namely, leiomyomas, leiomyosarcomas, until 1983, when electron microscopy and immunohistochemistry findings demonstrated a lack of smooth muscle and schwann cells. GISTs are now defined as spindle cell, epitheloid, or occasionally plemorphic mesenchymal tumors of the gastrointestinal tract, which express the KIT protein (CD117, stem cell factor receptor) detected at immunohistochemistry.
Here we are presenting a case of 33yrs old female with a palpable lump in the epigastrium and vague abdominal pain in the epigastric region. The patient had undergone both the endoscpic examination and Barium meal study and had come to us for the computed tomographic examination.
Keywords: Tumour, Gists, Epigastric
|How to cite this article:|
Arora A, Vaghani M, Shah S. Gastrointestinal stromal tumour of stomach. Indian J Radiol Imaging 2005;15:429-31
Here we are presenting a case of 33yr old female who presented to us with complaint of palpable lump in the epigastrium and vague abdominal pain in the epigastric region.
On Barium meal study, there was mucosal irregularity noticed in the fundus, body and pyloric antrum of the stomach with a large extrinsic impression noticed over the fundus and body of the stomach with a soft tissue opacity noticed medial to the fundus and along the lesser curvature. The gastro esophageal junction appeared to be normal. There was no definite evidence of any luminal narrowing noticed.
The patient had got done upper gastrointestinal endoscopic examination in which the esophagus appeared normal. There was a deep ulceration noted in the posterior wall of stomach along the lesser curvature. There was no definite evidence of any mass lesion or infiltration of the mucosa noted. On endoscopy the lesion was reported as gastric ulcer with localized perforation.
The patient had come to us for the computed tomographic examination. The CT study showed a large, minimally enhancing, (precontrast density of 20-25 HU, and post contrast density of 30-35HU) mass lesion arising from the wall of stomach with a large exogastric component and few necrotic areas within. The mass was medial to the fundus and lesser curvature of the stomach. There was a large ulcer crater noticed in the posterior wall of the stomach along the lesser curvature, thus confirming the endoscopic finding.
There was no lymphadenopathy noticed.
The Biopsy of the lesion was taken and it showed presence of smooth muscle cells of mesenchymal origin with increased mitotic figures and showing aggressive behaviour. The section was also sent for the immunohistochemical diagnosis and it turned out to be KIT receptor positive. Hence, the diagnosis of malignant GIST was made.
Most GISTs (70% -80%) are benign tumor with behavior varying according to the anatomic site of origin. Benign behavior is particularly common in gastric tumor, where benign tumors outnumber malignant one by a ratio of 3-5:1. The stomach and small bowel consistently account for the vast majority of case of GIST.
Clinically, presentations are dependent on tumor size. Small tumors are usually an incidental surgical finding, while large tumors are usually symptomatic. Symptoms include gastrointestinal hemorrhage, often with an acute episode, abdominal pain, a mass, weight loss, nausea, and vomiting. It is, however, difficult to predict the clinical behaviour of GIST and because pathologists believe that no GIST are truly benign, the 'benign' versus 'malignant' terminology is being replaced by the more useful distinction of 'low risk' versus 'high risk', and the phrase 'of uncertain malignant potential'.
On pathologic evaluation of the gross specimen GISTs are soft, fleshy, lobulated masses with a heterogeneous internal appearance and areas of necrosis and cystic degeneration.
GISTs are currently defined as KIT positive mesenchymal stromal tumours with specific histological character. On immunohistochemistry, the consistent expression of CD117 (KIT Protein) is seen in nearly all cases.
The malignant variety of the GISTs represents only about 3% of all malignant gastrointestinal tumours. It is known that about 10-30% of GISTs are malignant and the risk of malignancy increases with extragastric location, diameter greater than 5cms, and extension into the adjacent organs.
CT features of GIST include large, heterogeneous mass that extends outside the gastric wall, showing central necrosis and liquefaction. Large ulcerations and calcifications are other important features favoring malignant potential of the GIST.,
Until recently, patients with GIST have had limited treatment options. Prior to 2000, surgery was the only successful treatment option for GIST, and complete surgical resection of the disease trying to avoid tumour rupture is still the only treatment demonstrated to definitely cure the disease. However, even in patients whose tumours are completely removed and microscopically clean margins, there is a high probability of local tumour recurrence in the abdomen. The median time of recurrence being 19months.
Treatment options for the metastatic or recurrent GIST are even more limited and include surgery, systemic chemotherapy, and radiation. The probability of second recurrence after re-excision reaches 100%, with a median time of progression of less than 4months.
Radiation therapy is rarely used for the GIST because of the radiation sensitivity of the adjacent organs and the relative radioresistance of these tumours.
The response rate of GIST from older chemotherapy trials can be estimated between 0 and 15%.However, the tyrosine kinase inhibitor, Imatinib mesylate (Glivec) is the first rationally designed molecularly targeted drug therapy. Imatinib mesylate is a specific competitive inhibitor of the KIT receptor tyrosine kinase that is expressed in, and drives the development of GIST. It is being projected as the safe and effective systemic therapy currently available for this otherwise untreatable disease. However, larger and long term prospective study trials would be needed to test the efficacy of this drug.,
In our case, exploratory laparotomy was done with excision of the tumour performed. The patient is being followed up every three months on sonographic examination to specifically look for the recurrence of the disease.
| References|| |
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|2.||Florence Duffaud, Jean-Yves Blay. Gastrointestinal Stromal Tumours : Biology and Treatment. Oncology2003; 65: 187-197. |
|3.||Naitoh I, Okayama Y, Hirai M et al. Exophytic pedunculated gastrointestinal stromal tumor with remarkable cystic change. J Gastroenterol. 2003;38(12):1181-1184. |
|4.||Belloni M, De Fiori E, Mazzarol G et al. Endoscopic ultrasound and Computed Tomography in gastric stromal tumours. Radiol Med (Torino). 2002 Jan-Feb;103(1-2):65-73. |
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]