case_images: PMC4714509_01
case_images: PMC4714509_02
case_images: Computed tomography with intravenous and oral contrast from case 2. Coronal section of the abdomen and pelvis. Arrow points to 14.0 x 9.8 x 10.8 cm heterogeneous mass in the right upper quadrant abutting the ascending colon and duodenum. Oral contrast is seen within the mass. The fat plane between the mass and the second segment of the duodenum is obscured
case_images: 12957_2015_755_Fig1_HTML.jpg
case_images: PMC4714509_02_12957_2015_755_Fig1_HTML.jpg
case_images: Fig1
case_images: CT demonstrated a 14-cm heterogeneous mass in the right hemi-abdomen (Fig. 1). Colonoscopy revealed a partially obstructing tumor near the hepatic flexure (Fig. 2a), biopsies were consistent with adenocarcinoma, and immunohistochemistry revealed the absence of DNA mismatch repair enzymes hMSH2 and hMSH6 with retention of normal hMLH1 and hPMS2.
case_images: Endoscopy images, gross pathology, and histopathology from case 2. a Colonoscopy revealed an ulcerated, partially obstructing, large mass in the transverse colon (marked by asterisk). The pediatric colonoscope could not completely traverse this large mass due to tumor obstruction and alteration in the normal colon anatomy. b Upper endoscopy showed a large malignant ulcerated mass (marked by asterisk) with no bleeding in the second part of the duodenum. c Part of the surgical specimen including colon (marked by single arrow), duodenum (marked by double arrow), with the mass (marked by asterisk) with a diffusely mucinous appearance. d Hematoxylin and eosin stain of primary colonic adenocarcinoma (viewed at x40) with large pools of mucin evident. The tumor was 14 cm, low grade mucinous adenocarcinoma of the colon with loss of mismatch repair proteins and high microsatellite instability. There was mild to moderate intratumoral lymphocytes, mild to moderate peritumor lymphocytes, with low grade tumor budding, and no lymphovascular invasion. Margins were negative and 22 lymph nodes were negative (not shown)
case_images: 12957_2015_755_Fig2_HTML.jpg
case_images: PMC4714509_02_12957_2015_755_Fig2_HTML.jpg
case_images: Fig2
case_images: CT demonstrated a 14-cm heterogeneous mass in the right hemi-abdomen (Fig. 1). Colonoscopy revealed a partially obstructing tumor near the hepatic flexure (Fig. 2a), biopsies were consistent with adenocarcinoma, and immunohistochemistry revealed the absence of DNA mismatch repair enzymes hMSH2 and hMSH6 with retention of normal hMLH1 and hPMS2. Upper endoscopy revealed a 7-cm partially obstructing ulcerated mass in the second part of the duodenum (Fig. 2b); biopsies revealed a well-differentiated adenocarcinoma with immunostains suggesting a colonic primary (CK20/CDX2-positive, CK7-negative). Examination of the specimen revealed mucinous adenocarcinoma arising from the right colon with direct extension to the duodenal mucosa (Fig. 2c, d), and histopathology showed absence of DNA mismatch repair and high microsatellite instability (MSI-H).