{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T10:19:53Z","timestamp":1788776393433,"version":"build-2803163510"},"reference-count":25,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T00:00:00Z","timestamp":1767916800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Reports"],"abstract":"<jats:p>Background and Clinical significance: Cowden syndrome is an autosomal dominant disorder caused by germline loss-of-function mutations in the PTEN tumor suppressor gene. It is characterized by multiple hamartomas and an increased lifetime risk of malignancies affecting the breast, thyroid, endometrium, and gastrointestinal (GI) tract. Pediatric presentations may include macrocephaly, scrotal tongue, and intellectual disability. Gastrointestinal involvement is frequent, with juvenile-like hamartomatous polyps occurring in at least half of patients and distributed throughout the GI tract, posing a risk for malignant transformation. Early diagnosis and surveillance are crucial for improving patient outcomes. Case Presentation: We report a case of a 10-year-old Caucasian female with Cowden syndrome, with a history of a malignant germ cell tumor of the ovary consisting of a yolk sac tumor and low-grade immature teratoma diagnosed at age six, and thyroidectomy at age nine. The patient has mild intellectual disability. Routine radiological surveillance revealed a right colon intraluminal mass, prompting referral for pediatric gastroenterology evaluation. Endoscopy identified multiple polyps throughout the colon, stomach, and small intestine. Polypectomy of larger lesions was performed, and histopathology confirmed juvenile-like hamartomatous polyps without dysplasia or malignancy. This case highlights the necessity of comprehensive gastrointestinal evaluation in pediatric Cowden syndrome patients. Endoscopic surveillance is essential for early detection and management of polyps. Conclusions: Given the multisystem involvement and elevated cancer risk associated with PTEN mutations, a multidisciplinary approach that includes genetic counseling, dermatologic evaluation, and ongoing oncologic monitoring is recommended. Increased awareness of gastrointestinal manifestations enables timely intervention and may reduce morbidity and mortality in this high-risk population.<\/jats:p>","DOI":"10.3390\/reports9010021","type":"journal-article","created":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T08:09:06Z","timestamp":1767946146000},"page":"21","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Cowden Syndrome in Childhood: Gastrointestinal Involvement in a Multisystem Genetic Disorder\u2014A Case Report"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5617-2432","authenticated-orcid":false,"given":"Maria","family":"Rogalidou","sequence":"first","affiliation":[{"name":"Division of Gastroenterology & Hepatology, First Department of Paediatrics, National and\u00a0Kapodistrian, University of Athens \u2018Aghia Sophia\u2019 Children\u2019s Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0421-7712","authenticated-orcid":false,"given":"Nikolaos","family":"Katzilakis","sequence":"additional","affiliation":[{"name":"Department of Pediatric Hematology-Oncology, University Hospital of Heraklion, 71110 Crete, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kalliopi","family":"Stefanaki","sequence":"additional","affiliation":[{"name":"Pathology Department, Agia Sofia Children\u2019s Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-4581-9030","authenticated-orcid":false,"given":"Konstantina","family":"Dimakou","sequence":"additional","affiliation":[{"name":"Gastroenterology Department, Agia Sofia Children\u2019s Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dafni","family":"Margoni","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology & Hepatology, First Department of Paediatrics, National and\u00a0Kapodistrian, University of Athens \u2018Aghia Sophia\u2019 Children\u2019s Hospital, 11527 Athens, Greece"},{"name":"First Department\u00a0of Paediatrics, National and Kapodistrian, University of Athens \u2018Aghia Sophia\u2019 Children\u2019s Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5737-3770","authenticated-orcid":false,"given":"Iordanis","family":"Pelagiadis","sequence":"additional","affiliation":[{"name":"Department of Pediatric Hematology-Oncology, University Hospital of Heraklion, 71110 Crete, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra","family":"Papadopoulou","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology & Hepatology, First Department of Paediatrics, National and\u00a0Kapodistrian, University of Athens \u2018Aghia Sophia\u2019 Children\u2019s Hospital, 11527 Athens, Greece"},{"name":"Gastroenterology Department, Agia Sofia Children\u2019s Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3343-5110","authenticated-orcid":false,"given":"Eftichia","family":"Stiakaki","sequence":"additional","affiliation":[{"name":"Department of Pediatric Hematology-Oncology, University Hospital of Heraklion, 71110 Crete, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1038\/s41698-025-00847-3","article-title":"Extended spectrum of cancers in PTEN hamartoma tumor syndrome","volume":"9","author":"Yehia","year":"2025","journal-title":"NPJ Precis. 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