{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:01:44Z","timestamp":1785416504911,"version":"3.56.0"},"reference-count":17,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T00:00:00Z","timestamp":1776902400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100015763","name":"University of Szeged","doi-asserted-by":"publisher","award":["IV-114-1\/2026.SZAOK"],"award-info":[{"award-number":["IV-114-1\/2026.SZAOK"]}],"id":[{"id":"10.13039\/501100015763","id-type":"DOI","asserted-by":"publisher"}]},{"award":["IV-114-1\/2026.SZAOK"],"award-info":[{"award-number":["IV-114-1\/2026.SZAOK"]}],"id":[{"id":"https:\/\/ror.org\/01pnej532","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003825","name":"Hungarian Academy of Sciences","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100003825","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/02ks8qq67","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>A 27-year-old male presented with chronic diarrhea, bloating, and abdominal pain since age 13. Initially attributed to lactose intolerance, treated with dairy-free diet, symptoms persisted despite negative workup\u2014normal celiac serology, stool studies, and abdominal ultrasound. Recent symptoms included severe diarrhea, fatigue, weakness, 8 kg weight loss, hair loss, elevated IgE and fecal calprotectin. Gastroscopy showed flattened, granular gastric mucosa with focal hyperemia in the antrum and greater curvature. Histology revealed severe chronic inactive H. pylori-negative gastritis with a prominent subepithelial collagen band (verified by Crossmon\u2019s trichrome), confirming collagenous gastritis\u2014a rare entity first described in 1989. The condition has a slight female predominance and bimodal age peaks (adolescence and &gt;60 years). Symptoms are nonspecific, including abdominal pain, diarrhea, weight loss and anemia. Pediatric cases often feature nodular mucosa and anemia; adults more commonly present with watery diarrhea, sometimes linked to collagenous colitis. Diagnosis requires histological features including patchy subepithelial collagen band \u2265 10 \u03bcm thick, lymphocytic or eosinophilic infiltration of the lamina propria, epithelial changes and entrapped capillaries. Patterns include atrophic, lymphocytic-like, and eosinophil-rich. Crossmon\u2019s or Masson\u2019s trichrome, Congo red, and tenascin immunohistochemistry aid in proving collagen and excluding amyloidosis. Treatment is mainly symptomatic or with proton pump inhibitors; corticosteroids may be effective in refractory cases.<\/jats:p>","DOI":"10.3390\/diagnostics16091261","type":"journal-article","created":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T08:11:14Z","timestamp":1776931874000},"page":"1261","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Chronic Diarrhea and Weight Loss in a 27-Year-Old: Highlighting Collagenous Gastritis as a Rarely Encountered Entity"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-3262-8567","authenticated-orcid":false,"given":"\u00c1d\u00e1m","family":"Ferenczi","sequence":"first","affiliation":[{"name":"Department of Pathology, University of Szeged, 6725 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9434-2989","authenticated-orcid":false,"given":"Anita","family":"Sejben","sequence":"additional","affiliation":[{"name":"Department of Pathology, University of Szeged, 6725 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1552","DOI":"10.1016\/0016-5085(89)90403-4","article-title":"Collagenous gastritis","volume":"97","author":"Colletti","year":"1989","journal-title":"Gastroenterology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1111\/his.15542","article-title":"Collagenous gastritis: Clinical features, histologic correlates and unanswered questions","volume":"87","author":"Li","year":"2025","journal-title":"Histopathology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"265","DOI":"10.4253\/wjge.v7.i3.265","article-title":"Collagenous gastritis: Review","volume":"7","author":"Kamimura","year":"2015","journal-title":"World J. Gastrointest. Endosc."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1136","DOI":"10.1016\/j.dld.2021.03.010","article-title":"Collagenous gastritis: Epidemiology and clinical associations","volume":"53","author":"Genta","year":"2021","journal-title":"Dig. Liver Dis."},{"key":"ref_5","first-page":"3103","article-title":"Collagenous gastritis is an underdiagnosed cause of anaemia and abdominal pain: Systematic scoping review","volume":"68","author":"Kozai","year":"2023","journal-title":"Dig. Liver Dis."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1055\/s-2007-966730","article-title":"Collagenous gastritis","volume":"39","author":"Dray","year":"2007","journal-title":"Endoscopy"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1977","DOI":"10.1016\/j.cgh.2021.11.033","article-title":"Collagenous gastritis: Characteristics and response to topical budesonide","volume":"20","author":"Choung","year":"2022","journal-title":"Clin. 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Nutr."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/j.arcped.2023.03.013","article-title":"Collagenous gastritis in children: A national cohort","volume":"30","author":"Montero","year":"2023","journal-title":"Arch. Pediatr."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1111\/j.1443-1661.2012.01391.x","article-title":"Collagenous gastritis","volume":"25","author":"Jin","year":"2013","journal-title":"Dig. Endosc."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e00527","DOI":"10.14309\/crj.0000000000000527","article-title":"Collagenous gastritis masquerading as eosinophilic gastritis","volume":"8","author":"Klein","year":"2021","journal-title":"ACG Case Rep. 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