{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T09:15:02Z","timestamp":1775121302574,"version":"3.50.1"},"reference-count":10,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T00:00:00Z","timestamp":1774828800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Gastric-type lesions in the duodenum, including pyloric gland adenoma and gastric foveolar metaplasia, have been increasingly recognized for their unique histogenesis and potential link through the metaplasia\u2013neoplasia sequence. However, the coexistence of neoplastic and non-neoplastic gastric-type lesions within the same histological section has not been previously reported. Here, we present a case of a 73-year-old Japanese woman who underwent endoscopic submucosal dissection for a 34 \u00d7 20 mm elevated lesion in the duodenal bulb. Based on the preoperative biopsy results, pyloric gland adenoma was diagnosed; however, histopathological examination of the resected specimen revealed a far more complex picture. The main lesion consisted of two contiguous components: a hyperplastic polyp with gastric foveolar-type phenotype (Lesion I) and a pyloric gland adenoma mixed with gastric foveolar-type hyperplastic polyp (Lesion II). Importantly, the transitional zone between these components demonstrated histological continuity, with areas showing admixture of hyperplastic and adenomatous features within the same microscopic field. A separate hyperplastic polyp with gastric foveolar-type phenotype (Lesion III) was also identified, separated from Lesions I and II by intervening normal duodenal mucosa. All lesions shared a gastric-type mucin phenotype (MUC5AC-positive, CD10-negative), and extensive Brunner\u2019s gland hyperplasia was observed throughout the specimen. This case provides compelling morphological evidence for a histogenetic link between non-neoplastic gastric-type hyperplasia and pyloric gland adenoma, supporting the concept of a metaplasia\u2013neoplasia sequence in the duodenum. Furthermore, the presence of an additional separate lesion with the same phenotype suggests a field change in the development of gastric-type lesions.<\/jats:p>","DOI":"10.3390\/diagnostics16071045","type":"journal-article","created":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T13:41:53Z","timestamp":1774878113000},"page":"1045","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Gastric-Type Mixed Neoplastic and Non-Neoplastic Lesions in the Duodenal Bulb: A Case Supporting the Metaplasia\u2013Neoplasia Sequence"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0400-280X","authenticated-orcid":false,"given":"Hidetoshi","family":"Satomi","sequence":"first","affiliation":[{"name":"Department of Diagnostic Pathology and Cytology, Osaka International Cancer Institute, 3-1-69 Otemae, Osaka 541-8567, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noriya","family":"Uedo","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Osaka 540-0008, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shingo","family":"Ishiguro","sequence":"additional","affiliation":[{"name":"PCL Osaka Pathology & Cytology Center, Osaka 533-0031, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshiki","family":"Kairiku","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Osaka 540-0008, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomoki","family":"Michida","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Osaka 540-0008, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryu","family":"Ishihara","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Osaka 540-0008, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5193-5891","authenticated-orcid":false,"given":"Keiichiro","family":"Honma","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Pathology and Cytology, Osaka International Cancer Institute, 3-1-69 Otemae, Osaka 541-8567, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1111\/his.14275","article-title":"The pathology of gastric and duodenal polyps: Current concepts","volume":"78","author":"Kim","year":"2021","journal-title":"Histopathology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1007\/s00428-002-0750-6","article-title":"Pyloric gland adenoma: A clinico-pathological analysis of 90 cases","volume":"442","author":"Vieth","year":"2003","journal-title":"Virchows Arch."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1097\/PAS.0b013e31817d7ff4","article-title":"Pyloric gland adenoma: An entity distinct from gastric foveolar type adenoma","volume":"33","author":"Chen","year":"2009","journal-title":"Am. J. Surg. Pathol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1046\/j.1365-2559.1999.00681.x","article-title":"Histogenesis of gastric foveolar metaplasia following duodenal ulcer: A definite reparative lineage of Brunner\u2019s gland","volume":"35","author":"Kushima","year":"1999","journal-title":"Histopathology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1398","DOI":"10.1038\/bjc.2015.104","article-title":"Activating GNAS and KRAS mutations in gastric foveolar metaplasia, gastric heterotopia, and adenocarcinoma of the duodenum","volume":"112","author":"Matsubara","year":"2015","journal-title":"Br. J. Cancer"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1111\/his.13996","article-title":"Clinicopathological features of pyloric gland adenomas of the duodenum: A multicentre study of 57 cases","volume":"76","author":"Miller","year":"2020","journal-title":"Histopathology"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e70207","DOI":"10.1002\/deo2.70207","article-title":"Gastric foveolar-type hyperplastic polyp of the duodenum with GNAS and KRAS mutations: A potential precursor to neoplasia","volume":"6","author":"Yamazaki","year":"2025","journal-title":"DEN Open"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8883","DOI":"10.3748\/wjg.v22.i40.8883","article-title":"Pathophysiological and clinical aspects of gastric hyperplastic polyps","volume":"22","author":"Markowski","year":"2016","journal-title":"World J. Gastroenterol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Akaki, M., Taniguchi, S., Hatakeyama, K., Kushima, R., and Kataoka, H. (2014). Duodenal mucosal damage is associated with proliferative activity of Brunner\u2019s gland hamartoma: A case report. BMC Gastroenterol., 14.","DOI":"10.1186\/1471-230X-14-14"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1097\/PAS.0000000000000785","article-title":"Duodenal neoplasms of gastric phenotype: An immunohistochemical and genetic study with a practical approach to the classification","volume":"41","author":"Hida","year":"2017","journal-title":"Am. J. Surg. Pathol."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1045\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T08:07:44Z","timestamp":1775117264000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1045"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,30]]},"references-count":10,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["diagnostics16071045"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16071045","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,30]]}}}