Colon cancer with gastric invasion mimicking gastric submucosal tumor.

A 70-year-old woman presented to our outpatient department with several weeks of dull epigastric pain, belching, and early satiety. Physical examination revealed mild pallor and epigastric tenderness. Laboratory test results showed a leukocyte count of 14,400/mm3, hemoglobin of 10.7g/dL, and a positive fecal occult blood test. EGD disclosed an ovoid bulging mass at the posterior wall of the mid-gastric body (A, arrow) with intact overlying mucosa, a picture that suggested gastric submucosal tumor or external compression. CT showed a hypodense mass arising from the posterior greater curvature aspect of stomach (B, arrow), and extending to the adjacent colonic wall. EUS demonstrated a 4.5-cm exophytic dumbbell-shaped mass arising from the propria muscularis (C, arrow) with hyperechoic components (C, arrowheads); it was diagnosed as a GI stromal tumor. Colonoscopy found a stricture near the splenic flexure; biopsy specimens were negative for malignancy. During laparotomy, a 5-cm ill-defined tumor was found at the distal transverse colon with gastric invasion and regional lymph node involvement. Left hemicolectomy with lymph node dissection was performed, and pathology showed the tumor to be adenocarcinoma. (D, arrow, H&E. orig. mag. ×10). The final diagnosis was colon cancer with gastric invasion and lymph node involvement. She is currently receiving adjuvant chemotherapy and being followed in our oncology department.