{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T12:51:09Z","timestamp":1774615869473,"version":"3.50.1"},"reference-count":12,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T00:00:00Z","timestamp":1774569600000},"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>Protein-losing enteropathy (PLE) is an uncommon and often underrecognized manifestation of lymphoproliferative disorders and may be difficult to diagnose when conventional gastrointestinal investigations are unrevealing. We present an 82-year-old woman with recurrent hospital admissions initially spanning six months for diarrhea, weight loss, peripheral edema, and persistent hypoalbuminemia. Initial upper gastrointestinal endoscopy was normal, and colonoscopy was deferred due to intercurrent infection. Despite extensive laboratory and radiologic evaluation, including routine biochemical testing and imaging, the etiology of PLE remained unclear. Peripheral blood flow cytometry subsequently identified a small kappa-restricted monoclonal B-cell population compatible with marginal zone lymphoma, later confirmed on bone marrow biopsy, raising suspicion for gastrointestinal involvement. Video capsule enteroscopy demonstrated diffuse erosive and ulcerative disease throughout the small intestine, providing an anatomical explanation for the patient\u2019s protein loss. Following lymphoma-directed therapy, repeat capsule enteroscopy showed complete normalization of the small bowel mucosa. This case highlights the diagnostic value of combining peripheral blood flow cytometry and capsule endoscopy in unexplained protein-losing enteropathy, a rare and diagnostically challenging presentation of indolent lymphoma, and illustrates the role of capsule imaging in both disease localization and treatment monitoring. As a single-case report, these findings are not generalizable, and further studies are required to evaluate the broader applicability of this diagnostic approach.<\/jats:p>","DOI":"10.3390\/diagnostics16071006","type":"journal-article","created":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T11:32:47Z","timestamp":1774611167000},"page":"1006","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Capsule Endoscopy-Guided Diagnosis of Small Bowel Lymphoma Presenting as Protein-Losing Enteropathy: Complementary Role of Peripheral Blood Flow Cytometry"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-6057-9858","authenticated-orcid":false,"given":"Mohammed","family":"Abdulrasak","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, Lund University, 202 13 Malm\u00f6, Sweden"},{"name":"Department of Gastroenterology, Sk\u00e5ne University Hospital, 205 02 Malm\u00f6, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Olof","family":"Axler","sequence":"additional","affiliation":[{"name":"Department of Clinical Genetics and Pathology, Sk\u00e5ne University Hospital, 221 84 Lund, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bal\u00e1zs","family":"Kap\u00e1s","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, Sk\u00e5ne University Hospital, 221 85 Lund, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9314-9239","authenticated-orcid":false,"given":"Ervin","family":"Toth","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Lund University, 202 13 Malm\u00f6, Sweden"},{"name":"Department of Gastroenterology, Sk\u00e5ne University Hospital, 205 02 Malm\u00f6, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gajzer, D.C., and Fromm, J.R. (2025). Flow Cytometry for B-Cell Non-Hodgkin and Hodgkin Lymphomas. Cancers, 17.","DOI":"10.3390\/cancers17050814"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Yasui, S., Nishimura, K., Tanimoto, Y., Mugitani, M., Sugano, T., Sy-Janairo, M.L., Watanabe, D., Sakai, R., Yamada, H., and Saegusa, J. (2026). A Case of Diffuse Large B-Cell Lymphoma Presenting with Protein-Losing Enteropathy During Treatment for Systemic Lupus Erythematosus. Intern. Med.","DOI":"10.2169\/internalmedicine.5934-25"},{"key":"ref_3","first-page":"9351408","article-title":"Marginal Zone Lymphoma Complicated by Protein Losing Enteropathy","volume":"2016","author":"Stanek","year":"2016","journal-title":"Case Rep. Hematol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1174","DOI":"10.1055\/s-2005-921045","article-title":"Capsule Endoscopy in Gastrointestinal Lymphomas","volume":"37","author":"Flieger","year":"2005","journal-title":"Endoscopy"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"e000320","DOI":"10.1136\/bmjgast-2019-000320","article-title":"Gastrointestinal Lymphoma: The New Mimic","volume":"6","author":"Thomas","year":"2019","journal-title":"BMJ Open Gastroenterol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1097\/MCG.0b013e31823832ac","article-title":"Endoscopic and Imaging Findings in Protein-Losing Enteropathy","volume":"46","author":"Takenaka","year":"2011","journal-title":"J. Clin. Gastroenterol."},{"key":"ref_7","first-page":"22","article-title":"Protein-losing enteropathy: Diagnosis and management","volume":"41","author":"Copland","year":"2017","journal-title":"Pract. Gastroenterol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"968","DOI":"10.1016\/j.gie.2023.07.024","article-title":"Disease Surveillance Evaluation of Primary Small-Bowel Follicular Lymphoma Using Capsule Endoscopy Images Based on a Deep Convolutional Neural Network (with Video)","volume":"98","author":"Sumioka","year":"2023","journal-title":"Gastrointest. Endosc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"E1220","DOI":"10.1055\/a-1210-4830","article-title":"How to Read Small Bowel Capsule Endoscopy: A Practical Guide for Everyday Use","volume":"8","author":"Rondonotti","year":"2020","journal-title":"Endosc. Int. Open"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1177\/2050640619895864","article-title":"Nomenclature and Semantic Descriptions of Ulcerative and Inflammatory Lesions Seen in Crohn\u2019s Disease in Small Bowel Capsule Endoscopy: An International Delphi Consensus Statement","volume":"8","author":"Leenhardt","year":"2019","journal-title":"United Eur. Gastroenterol. J."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Su, C.-C., Chou, C.-K., Mukundan, A., Karmakar, R., Sanbatcha, B.F., Huang, C.-W., Weng, W.-C., and Wang, H.-C. (2025). Capsule Endoscopy: Current Trends, Technological Advancements, and Future Perspectives in Gastrointestinal Diagnostics. Bioengineering, 12.","DOI":"10.3390\/bioengineering12060613"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1055\/s-0044-1800916","article-title":"Capsule Endoscopy Technology: A New Era in Digestive Tract Examination","volume":"15","author":"Huang","year":"2024","journal-title":"J. Dig. Endosc."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1006\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T11:56:19Z","timestamp":1774612579000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1006"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,27]]},"references-count":12,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["diagnostics16071006"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16071006","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,27]]}}}