One of the most critical characteristics of colorectal cancer (CRC) is the difference between proximal (right-sided colon cancer, RCC) and distal (left-sided colon cancer, LCC) disease. The recent CRC studies showed the unique characteristics of RCC; RCCs were more prevalent in women than men and old patients, and the age difference between RCC and LCC was more apparent in women. Moreover, relatively poor protection against RCC by colonoscopy is a clearly hot issue for alarm. Thus, the left and right colon have been considered as dichotomous or even different organs in the view of molecular, histopathological, epidemiologic and clinical bases for over three decades. However, the evolutionary data suggesting linearity from the rectum to ascending colon beyond the simple right-left dichotomization in the views of cancer molecular features and site-specific clinicopathological differences, support the need for a paradigm shift to the colorectal continuum model rather than the traditional two-colon concept. This new multi-segmental or colorectal continuum hypothesis would provide both the better understanding of the complex etiology of colorectal carcinogenesis and the tailored preventive and therapeutic strategies for CRC including individualized CRC screening programs.
Adenoma/pathology ; Age Factors ; Colon, Ascending/pathology ; Colon, Descending/pathology ; Colorectal Neoplasms/genetics/*pathology ; Gene Expression Regulation, Neoplastic ; Humans ; Sex Factors

Adult intussusception represents 1% of patients with bowel obstruction and 5% of all intussusception. It presents with a variety of acute, intermittent and chronic symptoms, thus making its preoperative diagnosis is difficult. Overall, colonic intussusception in adults is most often related to a primary carcinoma and benign smooth muscle tumors of the gastrointestinal tract are uncommon. We experienced a case of adult intussusception of the colon caused by leiomyoma. The 18-year old man was suffered from intermittent, colicky left lower quadrant pain and bloody diarrhea. Physical examination revealed a mass in the left lower abdomen. An abdominal CT scan revealed a "target mass" in the distal colon. The patient was treated with segmental resection of the descending colon and anastomosis. Pathology revealed a benign leiomyoma of the distal colon as the leading point of the colo-colic intussusception. His postoperative course was uneventful and did well.
Abdomen ; Adolescent ; Adult* ; Colon* ; Colon, Descending ; Diagnosis ; Diarrhea ; Gastrointestinal Tract ; Humans ; Intussusception* ; Leiomyoma* ; Pathology ; Physical Examination ; Smooth Muscle Tumor ; Tomography, X-Ray Computed

BACKGROUND/AIMS: There have been several studies showing that retroflexion (RF) in the right colon (RC) could reduce the polyp miss rate of proximal colon during colonoscopy. This study was conducted to evaluate the additional benefit of RF technique in the RC. METHODS: Patients who underwent colonoscopy from May 2008 to April 2011 were enrolled in the study. Data were obtained by retrospectively reviewing the medical records. RF was attempted in every patients undergoing colonoscopy since May 2008 except in cases of small RC vault, co-morbidity, severe diverticulosis, failed RF despite two trials, complaints of severe abdominal pain, or time burden. At first, RC was examined under direct vision. It was then examined by RF to detect missed polyps during the initial observation. Finally, the RC was re-examined with direct view. RESULTS: The cumulative RF success rate in the RC was 78.84% (1,805 of 2,319). The RF success rate increased with the number of cases (50% at 160 cases, 70% at 400 cases, and reached near 90% over 1,000 cases). Few polyps (4.88%) were detected only with RF and the additional adenoma detection rate was 3.32%. The additional polyp/adenoma detection rates were higher in the old age group (p<0.01). There were no RF associated perforation or severe complication. CONCLUSIONS: Using RF examination, additional 4.88% of polyps could be detected in the RC. This technique could be a useful and safe method to detect hidden polyp during colonoscopy.
Adenoma/diagnosis/pathology ; Adult ; Aged ; Colon, Descending/pathology ; Colonic Neoplasms/diagnosis/pathology ; Colonic Polyps/*diagnosis ; *Colonoscopy ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies

Although colorectal granular cell tumors (GCTs) are rare, their incidental finding has increased as the use of diagnostic colonoscopy has become more common. Here we describe the case of a 41-yr-old man with a GCT in the descending colon that was detected after a screening colonoscopy. Endoscopic examination revealed a yellowish submucosal tumor, 13x12 mm in diameter, in the descending colon. Endoscopic mucosal resection (EMR) followed by histological examination revealed that the tumor was composed of plump histiocyte-like cells with an abundant granular eosinophilic cytoplasm and small round nuclei. The tumor cells expressed S-100 protein and stained with periodic acid-Schiff, but were negative for desmin and cytokeratin. The resected tumor was diagnosed as a GCT. Colonoscopists should consider the possibility of GCT in the differential diagnosis of yellowish submucosal tumors of the colon. In such patients, EMR seems to be a feasible and safe approach for diagnosis and treatment.
Adult ; *Colon, Descending/pathology ; Colonic Neoplasms/diagnosis/*pathology/surgery ; Colonoscopy ; Diagnosis, Differential ; Granular Cell Tumor/diagnosis/*pathology/surgery ; Humans ; Male ; S100 Proteins/metabolism

A colon cancer presenting as psoas muscle abscess is very rare. A 27-year-old woman was admitted with abdominal pain, fever, and discomfort on left thigh. She had been administered on anti-tuberculosis medication for colonic tuberculosis since 3 months ago. Abdominal CT scan revealed a mass lesion obstructing the descending colon with an abscess formation within left psoas muscle. We undertook segmental resection of obstructing descending colon after the percutaneous drainage of psoas abscess. The pathologic report was mucinous adenocarcinoma of the colon. We report the first case of colon cancer manifested with psoas abscess in Korea, with the review of literature associated with the correlation of colon cancer and tuberculosis.
Adenocarcinoma, Mucinous/complications/*diagnosis/pathology ; Adult ; Colectomy ; Colon, Descending ; Colonic Neoplasms/complications/*diagnosis/pathology ; Drainage ; Female ; Humans ; Psoas Abscess/*diagnosis/etiology ; Tomography, X-Ray Computed

PURPOSE: Postinfectiously irritable bowel syndrome (PI-IBS) develops in 3-30% of individuals with bacterial gastroenteritis. Recent studies demonstrated increases in inflammatory components in gut mucosa of PI-IBS patients even after complete resolution of infection. We aimed to investigate histological changes in colon and rectum of PI-IBS subjects after long term period of infection. MATERIALS AND METHODS: We recruited PI-IBS subjects who had been diagnosed IBS after complete resolution of enteritis caused by shigellosis outbreak 3 years earlier. We compared unmatched four groups, PI-IBS (n = 4), non PI-IBS (n = 7), D-IBS (n = 7, diarrhea predominant type) and healthy controls (n = 10). All of them underwent colonoscopic biopsy at three areas, including descending colon (DC), sigmoid colon (SC) and rectum, which were assessed for 5-hydroxytryptamine (5-HT)/peptide YY (PYY)-containing enterochromaffin (EC) cell, intraepithelial (IEL) and lamina propria T lymphocyte (CD3), CD8 lymphocytes, mast cells and CD68/calprotectin+ macrophages. RESULTS: All subjects had no structural or gross abnormalities at colonoscopy. In PI-IBS, 5-HT containing EC cells, PYY containing EC cells, IELs, CD3 lymphocytes, CD8 lymphocytes, mast cells, and CD68 + macrophages were increased compared to control (p < 0.05). In D-IBS, PYY containing EC cells, IELs, and CD3 lymphocytes were increased compared to control (p < 0.05). In PI-IBS, 5-HT containing EC cells tended to increase and PYY containing EC cells, CD8 lymphocytes, mast cells, and CD68+ macrophages were increased compared to non PI-IBS (p < 0.05). Calprotectin + marcrophages were decreased in PI-IBS, non PI-IBS and IBS compared to control. CONCLUSION: The immunoendocrine cells were sporadically increased in PI-IBS, non PI-IBS and D-IBS compared with control. Our findings in a very small number of patients suggest that mucosal inflammation may play a role in long-term PI-IBS, and that other sub-groups of IBS and larger scale studies are needed to confirm this observation.
Adult ; Antigens, CD/metabolism ; Antigens, Differentiation, Myelomonocytic/metabolism ; CD8-Positive T-Lymphocytes/cytology ; Case-Control Studies ; Colon, Descending/pathology ; Colon, Sigmoid/pathology ; Colonoscopy ; Dysentery, Bacillary/*complications ; Enterochromaffin Cells/cytology ; Female ; Humans ; Immunohistochemistry ; Intestinal Mucosa/*pathology ; Irritable Bowel Syndrome/metabolism/*pathology ; Macrophages/cytology ; Male ; Mast Cells/cytology ; Peptide YY/metabolism ; Rectum/pathology ; Serotonin/metabolism

OBJECTIVETo retrospectively analyze KRAS and BRAF gene mutation features in Chinese colorectal cancer (CRC) and their clinicopathologic relationship.

METHODS557 colorectal cancer cases were collected, including 325 colon cancer and 232 rectal cancer. PCR amplification and DNA sequencing were used to detect mutations in exon 2 of KRAS gene and exon 15 of BRAF gene mutation.

RESULTS(1) KRAS mutation was found in 40.4% (225/557) colorectal cancer. The most common mutation locations were in codon 12(79.1%, 178/225) and codon 13 (20.4%, 46/225). The most common mutation types were GGT > GAT (G12D) (37.8%, 85/225), GGT > GTT(G12V) (20.0%, 45/225) in codon 12 and GGC > GAC (G13D) in codon 13 (19.6%, 44/225). These three point mutations accounted 77.3% (174/225) in total KRAS gene mutation cases. All cases showed only one of point mutation types. (2) Among 557 CRC cases, KRAS mutation was significantly higher in female (46.2%, 92/199) than in man (37.2%, 133/358; P < 0.05). KRAS gene codon 13 mutation was higher in right colon cancer (11.3%, 12/106) than that in left colon cancer (4.8%, 6/124), but it didn't show any statistical significance (P > 0.05). (3) BRAF gene mutation was 5.1% (10/197) in colorectal cancer and 8/10 were the point mutation of GTG > GAG (V600E). Eight colorectal cancer cases with GTG > GAG (V600E) were not showing KRAS gene mutation. Both two cases with mutation on codon 600 (GTG > ATG, V600M) and codon 606 (GGG > AGT, G606S) showed codon 12 mutation of KRAS gene. (4) BRAF (V600E) gene mutation was higher in female (8.5%, 6/71) than that in male (1.6%, 2/126; P = 0.05); BRAF mutation in colon cancer (8.3%, 6/72) was higher than that in rectum cancer (2.1%, 2/94), but hadn't statistical significance (P > 0.05).

CONCLUSIONS(1) Codon 12, 13 in KRAS gene and codon 600 in BRAF gene are the most common mutation points in Chinese colorectal cancer. KRAS and BRAF mutations are mutually exclusive. (2) KRAS and BRAF gene mutation is higher in female than that in male, suggesting that RAS-RAF-MAPK signal pathway is probably related to hormones directly or indirectly. (3) There is a trend that codon 13 mutation in KRAS and codon 600 mutation in BRAF in right colon cancer are higher than that in left colon cancer, respectively, however, which needs more cases to be further verified.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Asian Continental Ancestry Group ; genetics ; Codon ; Colon, Ascending ; pathology ; Colon, Descending ; pathology ; Colonic Neoplasms ; genetics ; pathology ; Colorectal Neoplasms ; genetics ; pathology ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Proto-Oncogene Proteins ; genetics ; Proto-Oncogene Proteins B-raf ; genetics ; Proto-Oncogene Proteins p21(ras) ; Rectal Neoplasms ; genetics ; pathology ; Sex Factors ; Young Adult ; ras Proteins ; genetics