Stomach

Most GISTs arise from the stomach, accounting for 2% to 3% of all gastric tumors. According to a recently published study, 28 of 64 GISTs (44%) were located in the stomach.27 At CT, most tumors are large with an exogastric extension into the gastrohepatic ligament, gastrosplenic ligament, or the lesser sac.27 Most tumors have rim enhancement, with central areas of low attenuation due to hemorrhage, necrosis, or cystic degeneration (Figures 30.1-30.3). These findings have no correlation with malignant potential. Large tumors may also cav-itate, and the cavities may communicate with the gastric lumen and become filled with food residue, fluid, or air-fluid

figure 30.1. Large gastric gastrointestinal stromal tumor (GIST) in a 45-year-old man with history of abdominal pain and weight loss. (A) Coronal volume-rendered image through the upper abdomen reveals a large heterogeneous cystic and/or necrotic mass in the left upper quadrant that is inseparable from the stomach. Notice peripheral solid component with heterogeneous enhancement (arrow). The figure 30.1. Large gastric gastrointestinal stromal tumor (GIST) in a 45-year-old man with history of abdominal pain and weight loss. (A) Coronal volume-rendered image through the upper abdomen reveals a large heterogeneous cystic and/or necrotic mass in the left upper quadrant that is inseparable from the stomach. Notice peripheral solid component with heterogeneous enhancement (arrow). The

figure 30.2. Gastric GIST in a 92-year-old woman with early satiety, abdominal pain, and anemia. (A) Axial CT of the abdomen in the arterial phase reveals a large cystic/necrotic mass in the left upper quadrant, extending into the gastrosplenic ligament. The mass appears to arise from the posterior aspect of the stomach, which is displaced anteriorly (arrow). (B) Axial CT at the same level as (A) in figure 30.2. Gastric GIST in a 92-year-old woman with early satiety, abdominal pain, and anemia. (A) Axial CT of the abdomen in the arterial phase reveals a large cystic/necrotic mass in the left upper quadrant, extending into the gastrosplenic ligament. The mass appears to arise from the posterior aspect of the stomach, which is displaced anteriorly (arrow). (B) Axial CT at the same level as (A) in

mass abuts the liver without evidence of invasion. Oral contrast is seen in the large bowel from a prior computed tomography (CT) scan. (B) Coronal reconstruction reveals patency of portal vein (arrow) and superior mesenteric vein (small arrows). These findings are important for surgical planning.

the portal venous phase shows irregular enhancing peripheral solid components (arrow) and central necrosis. (C) Coronal volume-rendered image demonstrates the craniocaudal extension of the mass to the pelvis. (D) Sagittal reconstruction better reveals the extralu-minal nature of the mass. The mass is related to the posterior aspect of the stomach (arrow), which contains an air-fluid level.

imaging of gastrointestinal stromal tumor imaging of gastrointestinal stromal tumor

figure 30.2. (continued)

level (Figure 30.4). Homogeneous enhancement of the tumor is uncommon, accounting for 8% of cases according to one study.27 Calcifications are unusual and were reported in 3% of cases. Multidetector row CT with volume rendering allows for accurate delineation of the tumor outline and subtle gastric wall thickening at the site of tumor attachment to the gastric wall. These features help in determining the organ of origin in large tumors and their relationship to surrounding organs. CT may also demonstrate extragastric extension into the gastrohepatic ligament, gastrosplenic ligament, and lesser sac. It can demonstrate invasion of surrounding organs, ascites, or peritoneal carcinomatosis. Liver metastases may also be detected; these are usually hypovascular and best seen in the portal venous phase. Metastatic lymph node involvement is not observed in patients with GIST.

The differential diagnosis for gastric GISTs includes other mesenchymal neoplasms that arise in the gastric wall, including leiomyomas (Figure 30.5), leiomyosarcomas, schwanno-

ponents. This finding is somewhat atypical because most GISTs have an exophytic component. (B) Coronal reconstruction confirms the intraluminal nature of the mass. No extragastric extension was seen.

figure 30.3. Gastric GIST in a 48-year-old woman presenting with upper gastrointestinal bleeding. (A) Axial CT of the abdomen reveals a large mass (arrow) in the fundus of the stomach. The mass is entirely projecting into the gastric lumen, with no exophytic com ponents. This finding is somewhat atypical because most GISTs have an exophytic component. (B) Coronal reconstruction confirms the intraluminal nature of the mass. No extragastric extension was seen.

A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

Get My Free Ebook


Post a comment