Colorectal cancer (CRC) is a major global health concern. Its early diagnosis is extremely important, as it determines treatment options and strongly influences the length of survival. Histologic diagnosis can be made by pathologists based on images of tissues obtained from a colonoscopic biopsy. Convolutional neural networks (CNNs)-i.e., deep neural networks (DNNs) specifically adapted to image data-have been employed to effectively classify or locate tumors in many types of cancer. Colorectal histology images of 28 normal and 29 tumor samples were obtained from the National Cancer Center, South Korea, and cropped into 6806 normal and 3474 tumor images. We developed five modifications of the system from the Visual Geometry Group (VGG), the winning entry in the classification task in the 2014 ImageNet Large Scale Visual Recognition Competition (ILSVRC) and examined them in two experiments. In the first experiment, we determined the best modified VGG configuration for our partial dataset, resulting in accuracies of 82.50%, 87.50%, 87.50%, 91.40%, and 94.30%, respectively. In the second experiment, the best modified VGG configuration was applied to evaluate the performance of the CNN model. Subsequently, using the entire dataset on the modified VGG-E configuration, the highest results for accuracy, loss, sensitivity, and specificity, respectively, were 93.48%, 0.4385, 95.10%, and 92.76%, which equates to correctly classifying 294 normal images out of 309 and 667 tumor images out of 719.

Mutations in CDH1, which encodes E-cadherin, have been associated with hereditary diffuse gastric cancer (HDGC) in Western populations but have not been shown to play a major role in Asians. Recently, a patient with familial gastric cancer (FGC) was shown to harbor a germline mutation in the TP53 gene, which encodes p53 and has been previously associated with LiFraumeni Syndrome (LFS). To determine whether mutations in TP53 are associated with FGC in Asians, we screened the entire coding region of TP53 in probands from 23 Korean FGC families. We identified a nonsense (E287X) TP53 germline mutation in a family whose history is compatible with both HDGC and LFS. Two members of this family (SNU-G2) were afflicted with brain tumors, seven with gastric cancers, two with sarcomas, and one with both gastric cancer and a sarcoma. The E287X TP53 mutation segregated with the cancer phenotype in the family members from whom DNA samples were available. To our knowledge, this is the first report of a large family with both HDGC and LFS. Our results suggest that TP53 mutational screening in FGC families should be interpreted with caution because additional TP53 mutation-carrying HDGC families may also show LFS-related phenotypes.

Mesenchymal hamartoma (MH) of the liver is an uncommon benign lesion related to ductal plate malformation. It is usually cystic and mainly composed of myxoid mesenchymal tissue with tortuous or cystic bile ducts. In order to characterize the clinicopathological features of MH, the Korean Gastrointestinal Pathology Study Group collected a total of 17 MH cases diagnosed in 7 hospitals from 1992 to 2002 and compared the clinicopathologic findings of cystic MH with those of solid variant. Among the 17 cases, 7 (41%) were solid. The solid form showed a higher serum level of α-fetoprotein (AFP), the smaller bile ducts, and more frequent proliferation of vessels. Serum AFP level was related to the amount of hepatocytes. Two of seven solid cases harbored a larger amount of evenly distributed hepatocytes and proliferation of small duct with focal hepatocyte-bile duct transition. These histologic findings are similar to those of mixed hamartoma. Therefore, the mixed hamartoma and the MH of both solid and cystic types could be the variants of one disease spectrum. And hepatocytes within MH might be rather a genuine tumor component than entrapped into the tumor. In conclusion, MH can show various clinicopathological features and recognition of these features will facilitate accurate diagnosis of MH.

OBJECTIVE:Self-expanding metallic stents (SEMS) are useful palliative option and a bridge to surgery in malignant colorectal obstruction. The aim of this study was to evaluate the clinical outcomes of SEMS to palliate colorectal malignant obstruction. METHODS:Malignant colorectal obstructive patients who underwent SEMS insertion at the National Cancer Center, Korea from January 2004 to June 2008 were enrolled in the study. Patients' clinical characteristics, outcomes and complications for palliative SEMS insertion were retrospectively analyzed. RESULTS:A total of 54 patients were enrolled in the palliative SEMS group and 48 patients with obstructive CRC were included in the SEMS as the bridge to surgery group. Obstruction of the left colon occurred in 52 patients of the palliative SEMS group and all patients in SEMS as bridge to surgery group. For primary SEMS insertion, the technical success (TS) rate was 87.0% and the clinical success (CS) rate 89.4%, while the rates of early and late complications were 24.1% and 23.4%, respectively. There was no procedure-related mortality. Stent migration rate was higher in the cases treated with small diameter and covered type of stents. Median time to reobstruction and migration were 85 and 101 days, respectively. TS and CS rates for SEMS reinsertion were comparable to those for primary SEMS insertion. CONCLUSIONS:Palliative SEMS are effective and favorable procedures for malignant colorectal obstruction but with some complications. Stent migration is associated with covered type and small diameter stents while other factors including length of stent and chemotherapy do not affect stent complications in the present study.

The histopathological diagnosis of gastric mucosal biopsy and endoscopic mucosal resection/endoscopic submucosal dissection specimens is important, but the diagnostic criteria, terminology, and grading system are not the same in the East and West. A structurally invasive focus is necessary to diagnose carcinoma for most Western pathologists, but Japanese pathologists make a diagnosis of cancer based on severe dysplastic cytologic atypia irrespective of the presence of invasion. Although the Vienna classification was introduced to reduce diagnostic discrepancies, it has been difficult to adopt due to different concepts for gastric epithelial neoplastic lesions. Korean pathologists experience much difficulty making a diagnosis because we are influenced by Japanese pathologists as well as Western medicine. Japan is geographically close to Korea, and academic exchanges are active. Additionally, Korean doctors are familiar with Western style medical terminology. As a result, the terminology, definitions, and diagnostic criteria for gastric intraepithelial neoplasia are very heterogeneous in Korea. To solve this problem, the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists has made an effort and has suggested guidelines for differential diagnosis: (1) a diagnosis of carcinoma is based on invasion; (2) the most important characteristic of low grade dysplasia is the architectural pattern such as regular distribution of crypts without severe branching, budding, or marked glandular crowding; (3) if nuclear pseudostratification occupies more than the basal half of the cryptal cells in three or more adjacent crypts, the lesion is considered high grade dysplasia; (4) if severe cytologic atypia is present, careful inspection for invasive foci is necessary, because the risk for invasion is very high; and (5) other structural or nuclear atypia should be evaluated to make a final decision such as cribriform pattern, papillae, ridges, vesicular nuclei, high nuclear/cytoplasmic ratio, loss of nuclear polarity, thick and irregular nuclear membrane, and nucleoli.