PMC4602947_01
(A) Diagram of colon. (B) Representative endoscopic image of inflammatory scars in the cecum. (C) Representative endoscopic image of the intestinal stricture in the transverse colon (oral side) and inflammatory scars in the hepatic flexure. (D) Representative endoscopic image of the transverse colon (anal side) intestinal stricture caused by inflammatory polyps. (E) Representative endoscopic image of descending colon showing loss of the typical vascular pattern and haustra, indicating coarse, inflammed mucosa. (F) An endoscopic image of the proctosigmoid colon reveals normal mucosa.
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F1
The colonoscopy revealed, in the observation range, many scars caused by inflammation in the cecum and ascending colon, an intestinal stricture caused by inflammatory polyps in the transverse colon (Figure 1A-D), loss of both visible vascular patterns and haustra in the descending colon (Figure 1E), and normal mucosa in the sigmoid colon (Figure 1F), rectum, and ileum. We performed colonoscopy 4 times for 20 months since the fecal occult blood test was positive and each biopsy indicated colitis but no obvious malignancy (Figure 2C, Table 1).
(A) Histopathological examination of colonic mucosa reveals basophilic fringes on the luminal surface of intestinal mucosa (black arrows) and infiltration of lymphocytes and eosinophils in a subepithelial lesion. (Hematoxylin and eosin stain, x400). (B) At the initial evaluation, findings included colonic mucosa with infiltration of lymphocytes and eosinophils in a subepithelial lesion with no obvious dysplastic changes. (Hematoxylin and eosin stain, x200). (C) Eight months after the initial evaluation, colonic mucosa contains an infiltration of lymphocytes and eosinophils with no obvious atypical colonic glands. (Hematoxylin and eosin stain, x200).
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F2
Examination of biopsies from each segment of colon (including even specimens from normal mucosa) revealed chronic colitis accompanied by IS, as evidenced by basophilic fringes on the luminal surface of the intestinal mucosa and infiltration of lymphocytes and eosinophils in subepithelial lesions (Figure 2A). There were no obvious dysplastic changes (Figure 2B). We performed colonoscopy 4 times for 20 months since the fecal occult blood test was positive and each biopsy indicated colitis but no obvious malignancy (Figure 2C, Table 1).
(A) Computed tomography (CT) of abdomen revealed wall thickening of the transverse colon around the hepatic flexure (white arrowhead) at the initial evaluation. (B) and (C) At 20 mo after the initial evaluation, abdominal CT revealed exacerbation of the intestinal stricture in the transverse colon around the hepatic flexure (B, white arrow), dilatation of the ascending colon (C, black arrowhead), and extraintestinal fluid accumulation, which indicated abscess formation (C, black arrow).
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F3
Abdominal computed tomography (CT) revealed wall thickening in the transverse colon around the hepatic flexure (Figure 3A). Abdominal CT revealed exacerbation of the intestinal stricture in the transverse colon around the hepatic flexure (Figure 3B) and dilatation of the ascending colon with extraintestinal fluid (Figure 3C).
(A) Gross histology revealed circumferential coarse mucosa due to tumor formation in the transverse colon (white arrow). (B) On cross-section, the tumor was composed of cystic lesions that contained mucin (white arrowhead). (C)-(E) Histopathological examination revealed features of mucinous adenocarcinoma, including formations resembling lakes of mucin. Mucinous columnar epithelium glands with mild atypia infiltrated the muscularis propia and subserosal fatty tissue layers. (Hematoxylin and eosin stain - (C): x40, (D): x100, (E): x200.)
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F4
Histopathological examination of the specimens revealed MC that had infiltrated into the muscularis propia and subserous layers of the visceral peritoneum, purulent peritonitis due to perforation within the tumor and lymph node metastasis (Figure 4).
Immunohistochemical staining for DNA mismatch repair protein showed normal expression of MLH1, MLH2, PMS2, and MSH6. (x200).
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F5
An immunohistochemical stain for DNA MMR proteins, including MLH1, MSH2, PMS2, and MSH6, revealed no lack of these expressions (Figure 5).