Metastatic carcinoma occurring in a gastric hyperplastic polyp mimicking primary gastric cancer: the first reported case. Case Rep Pathol. 2014;2014:781318. [PMID: 25400965 PMCID: PMC4221967 DOI: 10.1155/2014/781318]

Deficiency of Stomach-Type Claudin-18 in Mice Induces Gastric Tumor Formation Independent of H pylori Infection

BACKGROUND & AIMS

Epithelial cells are joined by tight junctions (TJs) to form a cell sheet. In the stomach, epithelial cell sheet forms an essential barrier against gastric material, including gastric acid. Although the decreased expression of stomach-type claudin-18 (stCldn18), a TJ protein, is generally observed in human gastritis and gastric cancer, its pathological roles are not fully understood. We previously reported that mice lacking stCldn18 (stCldn18-/-) exhibit gastric acid leakage through TJs, which induces active gastritis at a young age. Here, we examined the gastric pathologies in mice after long-term stCldn18 deficiency.

METHODS

The gastric pathologies in stCldn18-/- mice were sequentially analyzed from youth to old age, and compared to those in humans. To examine the relationship between stCldn18 deficiency-induced gastric pathologies and Wnt-dependent tumorigenesis, we generated Wnt1-overexpressing stCldn18-/- mice.

RESULTS

StCldn18-/- mice developed chronic active gastritis at middle age, with expression of the chemoattractant CCL28. At old age, 20-30% of these mice developed gastric tumors with CXCL5 expression, indicative of EMT. In this process, spasmolytic polypeptide-expressing metaplasia (SPEM) cells appeared. Increased expressions of CD44-variants, TLR2, and CXCL5 indicated age-dependent changes in cell characteristics. Some features of the stCldn18-/- mouse gastric tumorigenesis resembled H pylori-infection-related human carcinogenesis. The gastric tumorigenesis was accelerated in Wnt1-overexpressing stCldn18-/- mice, indicating that Wnt is involved in the stCldn18-/- mouse gastric tumorigenesis.

CONCLUSIONS

StCldn18 deficiency induced gastric tumorigenesis in mice without H pylori infection. Our findings revealed that several signaling networks, including the cytokine-, stemness-, and Wnt-signaling pathways, may be activated under the stCldn18-deficiency-induced chronic active gastritis to accelerate the gastric tumorigenesis.

[Gastric adenocarcinoma arising in giant hyperplastic polyp]

Gastric hyperplastic polyps are usually solitary, their development is supposed to be associated with excessive proliferation of foveolar cells. It is essential to differentiate hyperplastic polyps from other sporadic polyps (adenomatous and fundic gland polyps) and lesions, included in familial polyposis syndromes. The frequency of adenocarcinoma in large gastric hyperplastic polyps (more than 1-2 cm in size) is about 2,1%. This article includes case report of gastric adenocarcinoma arised in large hyperplastic polyp in a 56-year-old patient. On histological examination a well-differentiated adenocarcinoma without invasion in the peduncle was identified. Immunohistochemically cells of adenocarcinoma showed elevated expression of claudin-3, CDX2, p53 and Ki67 compared to hyperplastic glands and dysplastic areas of the polyp. Also focal expression of MUC2 was revealed in adenocarcinoma. Expression of MUC5AC, CD44 and cyclin D1 was less prominent in cancer areas compared to hyperplastic and dysplastic glands. Levels of expression of claudin-1, claudin-4 and β-catenin were equal in adenocarcinoma and hyperplastic structures. Control endoscopic examination with following morphologic examination was performed three months after surgical operation. No signs of tumor growth were identified.

Gastric metastases from gynaecologic tumors: case reports and review of the literature

The stomach is an infrequent localization of tumor metastases, and metastases originating from primary gynaecological cancers are particularly rare. We described the case of three females with ovarian, uterine, and breast metastases in the stomach, and we performed a systematic review of the literature of cases diagnosed at endoscopy. Overall, data of 18 patients with gastric metastases originating from the ovary, 11 from the uterus, and 159 from breast cancer were analyzed. Therefore, gastric metastasis mainly occurs from breast cancer, whilst both ovarian and uterine metastases are distinctly less frequent, but not impossible.

Pathophysiological and clinical aspects of gastric hyperplastic polyps

Gastric polyps become a major clinical problem because of high prevalence and tendency to malignant transformation of some of them. The development of gastric hyperplastic polyps results from excessive proliferation of foveolar cells accompanied by their increased exfoliation, and they are macroscopically indistinguishable from other polyps with lower or higher malignant potential. Panendoscopy allows detection and differentiation of gastric polyps, usually after obtaining histopathological biopsy specimens. Unremoved gastric hyperplastic polyps may enlarge and sometimes spontaneously undergo a sequential progression to cancer. For this reason, gastric hyperplastic polyps larger than 5 mm in size should be removed in one piece. After excision of polyps with atypical focal lesion, endoscopic surveillance is suggested depending on histopathological diagnosis and possibility of confirming the completeness of endoscopic resection. Because of the risk of cancer development also in gastric mucosa outside the polyp, neighboring fragments of gastric mucosa should undergo microscopic investigations. This procedure allows for identification of patients who can benefit most from oncological endoscopic surveillance. If Helicobacter pylori (H. pylori) infection of the gastric mucosa is confirmed, treatment strategies should include eradication of bacteria, which may prevent progression of intestinal metaplasia. The efficacy of H. pylori eradication should be checked 3-6 mo later.