Differential diagnosis of solitary gastric Peutz-Jeghers-type polyp with stomach cancer: a case report.

INTRODUCTION: Solitary Peutz-Jeghers-type polyps of the stomach are extremely rare. They are defined as unique polyps that are not associated with Peutz-Jeghers syndrome (PJS). PRESENTATION OF CASE: A 37-year-old woman presented at our hospital with anemia and epigastric discomfort. Esophagogastroduodenoscopy to determine the cause of anemia revealed a 5 × 6-cm pedunculated polypoid tumor at the greater curvature of the upper gastric body. Pathological examination of a biopsy specimen confirmed a Group 1 hyperplastic polyp. Computed tomography revealed neither lymph node swelling nor distant metastasis. A malignant component of the polypoid tumor was difficult to deny because of its size. The patient underwent local resection of the stomach. Her postoperative course was uneventful. A pathological examination of the surgical specimen revealed a Peutz-Jeghers-type, hamartomatous polyp containing an enlarged crypt with hyperplastic foveolar epithelium and smooth muscle proliferating into the lamina propria. No atypical cells were found in the overlying epithelium. Based on these findings, we performed colonoscopy and capsule endoscopy of the intestine. No polyps were found in the intestine or colon. She had no family history of any type of tumor and no mucocutaneous pigmentation. DISCUSSION: There were only 10 reports of solitary gastric Peutz-Jeghers polyps published to date. Although most of them did not have atypical cells, one case has proliferative component. A few reports have described relationship with malignant tumor. CONCLUSION: Solitary gastric PJ-type polyps are rare. Careful follow-up should be recommended and further studies are needed to evaluate cancer risk of solitary gastric PJ-type polyps.

Gastric carcinogenesis by N-Methyl-N-nitrosourea is enhanced in db/db diabetic mice.

In 2005, a Japanese epidemiological study showed that increase in plasma glucose levels is a risk factor for gastric cancer. However, no animal model has hitherto shown any association between diabetes mellitus and neoplasia in the stomach. Diabetic (db/db) mice have obese and diabetic phenotypes, including hyperglycemia, because of disruption of the leptin receptor. In the present study, effects of hyperglycemia and/or hyperinsulinemia on the development of proliferative lesions were therefore examined in db/db mice given N-methyl-N-nitrosourea (MNU). A total of 120 mice were assigned to four groups: Group A, 40 db/db mice with MNU; Group B, 40 + /db mice with MNU; Group C, 30 misty (wild-type) mice with MNU; Group D, 10 db/db mice without MNU. MNU was given at 60 ppm in drinking water for 20 weeks. Subgroups of animals were sacrificed at weeks 21 and 30 and blood samples were collected to measure glucose, insulin, leptin, and adiponectin concentrations. The removed stomachs were fixed in formalin, and embedded in paraffin for histological examination and immunohistochemistry. At week 30 in Groups A, B, C and D, hyperplasia was observed in 100, 79, 57, and 0%, and dysplasia in 91, 43, 71, and 0%, respectively. Adenocarcinomas and pepsinogen-altered pyloric glands (PAPG), putative preneoplastic lesions, were observed only in Group A, at an incidence of 45%. The serum levels of insulin and leptin were also elevated in Group A. Gastric carcinogenesis by MNU was enhanced in db/db mice, possibly in association with hyperinsulinemia and hyperleptinemia.

Emergence of spasmolytic polypeptide-expressing metaplasia in Mongolian gerbils infected with Helicobacter pylori.

Spasmolytic polypeptide (TFF2)-expressing metaplasia (SPEM) is observed in mucosa adjacent to human gastric cancer and in fundic glands showing oxyntic atrophy in Helicobacter felis-infected mice. Mongolian gerbils infected with Helicobacter pylori (Hp) develop goblet cell intestinal metaplasia and adenocarcinoma, but the presence of SPEM has not been studied in gerbils. We therefore have sought to examine the development of metaplastic mucosal changes in Hp-infected Mongolian gerbils. Mongolian gerbils were assigned to either uninfected controls or infected with Hp at 17 weeks of age. The animals were killed at 17, 20, 26, 31, 41 and 56 weeks of age. Stomach sections were stained using antibodies for TFF2, intrinsic factor, H/K-ATPase, BrdU and MUC2. Dual immunofluorescence staining for TFF2 with intrinsic factor and for TFF2 with MUC2 was performed. In uninfected animals, no SPEM or intestinal metaplasia was observed. Infected gerbils developed SPEM initially in the intermediate zone along the lesser curvature and subsequently spread out towards the greater curvature. In the earlier stages of infection, SPEM glands demonstrated TFF2 and intrinsic factor double staining cells. However, after 35 weeks of infection, the number of double staining SPEM cells decreased. While early in infection SPEM organized in straight glands, in the later stages of infections, SPEM glands became distorted or dilated along with the development of gastritis cystica profunda that was TFF2 positive. Goblet cell intestinal metaplasia developed only late in the infection. Dual staining for TFF2 and MUC2 showed glands containing both SPEM- and MUC2-positive goblet cell intestinal metaplasia. SPEM develops early in Hp infection in Mongolian gerbils, and alterations in gland morphology arise from SPEM glands during the course of gastric infection with goblet cell intestinal metaplasia developing subsequent to SPEM.

Helicobacter pylori-negative / API2-MALT1 translocation-negative low-grade MALT lymphoma.

A 71-year-old man with a Helicobacter pylori infection-negative and API2-MALT1 translocation-negative extranodal marginal-zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type of the stomach has been followed conservatively for over 5 years. The lesion has shown no major morphological changes or malignant progression into a diffuse large-cell type during the time course. The absence of genetic translocation of API2-MALT1 was confirmed with fluorescence in situ hybridization (FISH). The prognosis of H. pylori-negative and API2-MALT1 translocation-negative low-grade MALT lymphoma is unknown, and a standard treatment for such lymphoma has yet to be defined. The case of MALT lymphoma negative for both of the above factors that we report has shown no obvious rapid progression or malignant change over the long-term course. Although curative operation and/or chemoradiotherapy should still be discussed as the treatment of choice, the treatment of this type of lymphoma must be carefully determined on a case-by-case basis, according to its biological status and prognosis.