{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T06:15:08Z","timestamp":1783318508808,"version":"3.54.6"},"reference-count":19,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T00:00:00Z","timestamp":1783296000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Pediatr."],"abstract":"<jats:p>\n                    Mediastinal actinomycosis is rare in children, and when it presents as a mass-like lesion, its clinical and imaging features overlap substantially with lymphoma, making differential diagnosis extremely challenging. We report a 2-year-1-month-old girl admitted with fever and cough. Contrast-enhanced chest computed tomography (CT) showed multiple enlarged mediastinal and bilateral hilar lymph nodes coalescing into a mass-like lesion with heterogeneous enhancement and small hypoenhancing foci, encasement of adjacent mediastinal vessels, and compression of the left main bronchus and the origin of the lingular bronchus. Magnetic resonance imaging (MRI) demonstrated heterogeneous signal intensity and enhancement; the radiologic differential included lymphoproliferative and granulomatous disease. Bone marrow biopsy, leukemia immunophenotyping, and tumor markers did not support malignancy. Ultrasound-guided biopsy of the mediastinal lesion revealed necrotizing granulomatous inflammation. Metagenomic next-generation sequencing (mNGS) of unstained tissue sections detected\n                    <jats:italic>Actinomyces oris<\/jats:italic>\n                    with mixed oropharyngeal flora, while\n                    <jats:italic>Mycobacterium tuberculosis<\/jats:italic>\n                    complex, fungi, viruses, and atypical pathogens were not detected. Pulmonary inflammation improved with antimicrobial therapy; however, repeat CT on January 28, 2026 showed little change in the mediastinal\u2013hilar lesions. Because lymphoma could not be excluded, thoracoscopic partial resection was performed at another hospital, and postoperative pathology again showed granulomatous inflammation with caseous necrosis and negative acid-fast staining. Oral amoxicillin\u2013clavulanate was continued postoperatively, in line with the principle of 2\u20136 weeks of intravenous therapy followed by 6\u201312 months of oral antibiotics for thoracic actinomycosis, with duration individualized to residual disease, imaging response, and drug tolerance. Follow-up ultrasonography on April 13, 2026 demonstrated reduction of the residual lesion, and the patient remained asymptomatic. This case highlights that pediatric mediastinal actinomycosis can mimic lymphoma and that integrated assessment of deep-tissue pathology, mNGS, serial imaging, and treatment response can guide diagnostic and therapeutic decision-making, preventing misdiagnosis and mistreatment.\n                  <\/jats:p>","DOI":"10.3389\/fped.2026.1882250","type":"journal-article","created":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T05:37:08Z","timestamp":1783316228000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Pediatric mediastinal actinomycosis mimicking lymphoma diagnosed by tissue metagenomic next-generation sequencing"],"prefix":"10.3389","volume":"14","author":[{"given":"Meng","family":"Yi","sequence":"first","affiliation":[{"name":"Department of Hematology and Oncology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ying","family":"Dai","sequence":"additional","affiliation":[{"name":"Department of Hematology and Oncology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chao","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Hematology and Oncology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huiping","family":"Lang","sequence":"additional","affiliation":[{"name":"Department of Hematology and Oncology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xianping","family":"Jiang","sequence":"additional","affiliation":[{"name":"Department of Pathology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiuli","family":"Yuan","sequence":"additional","affiliation":[{"name":"Department of Hematology and Oncology, Shenzhen Children\u2019s Hospital","place":["Shenzhen, Guangdong, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,6]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"183","DOI":"10.2147\/IDR.S39601","article-title":"Actinomycosis: etiology, clinical features, diagnosis, treatment, and management","volume":"7","author":"Valour","year":"2014","journal-title":"Infect Drug Resist"},{"key":"B2","doi-asserted-by":"publisher","first-page":"419","DOI":"10.1128\/CMR.00100-14","article-title":"Actinomyces and related organisms in human infections","volume":"28","author":"K\u00f6n\u00f6nen","year":"2015","journal-title":"Clin Microbiol Rev"},{"key":"B3","doi-asserted-by":"publisher","first-page":"490","DOI":"10.1016\/j.jiph.2023.02.004","article-title":"The diagnosis and management of pulmonary actinomycosis","volume":"16","author":"Boot","year":"2023","journal-title":"J Infect Public Health"},{"key":"B4","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1016\/j.prrv.2021.09.001","article-title":"Paediatric pulmonary actinomycosis: a forgotten disease","volume":"43","author":"Goussard","year":"2022","journal-title":"Paediatr Respir Rev"},{"key":"B5","doi-asserted-by":"publisher","first-page":"1186","DOI":"10.1148\/rg.2021200180","article-title":"Mediastinal masses in children: radiologic-pathologic correlation","volume":"41","author":"Biko","year":"2021","journal-title":"Radiographics"},{"key":"B6","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1007\/BF02303555","article-title":"Mediastinal tumors in children: experience with 196 cases","volume":"1","author":"Grosfeld","year":"1994","journal-title":"Ann Surg Oncol"},{"key":"B7","doi-asserted-by":"publisher","first-page":"541","DOI":"10.1007\/BF02012144","article-title":"Multifocal thoracic actinomycosis simulating lymphoma","volume":"23","author":"Wu","year":"1993","journal-title":"Pediatr Radiol"},{"key":"B8","doi-asserted-by":"publisher","first-page":"52","DOI":"10.7883\/yoken.JJID.2006.52","article-title":"Actinomycosis as a neglected diagnosis of mediastinal mass","volume":"59","author":"Alborzi","year":"2006","journal-title":"Jpn J Infect Dis"},{"key":"B9","doi-asserted-by":"publisher","first-page":"409","DOI":"10.18683\/germs.2022.1346","article-title":"Actinomyces in the mediastinum. Surprise is key in all art","volume":"12","author":"Severiche-Bueno","year":"2022","journal-title":"Germs"},{"key":"B10","doi-asserted-by":"publisher","first-page":"e00534","DOI":"10.1002\/rcr2.534","article-title":"Unusual aetiology of lymphocyte-predominant exudative pleural effusion: primary mediastinal actinomycosis","volume":"8","author":"Seong","year":"2020","journal-title":"Respirol Case Rep"},{"key":"B11","doi-asserted-by":"publisher","first-page":"d6099","DOI":"10.1136\/bmj.d6099","article-title":"Actinomycosis","volume":"343","author":"Wong","year":"2011","journal-title":"BMJ"},{"key":"B12","doi-asserted-by":"publisher","first-page":"125","DOI":"10.1177\/0036933018789312","article-title":"Masking and misleading: concomitant actinomycosis and B-cell lymphoma\u2014a case report and review of literature","volume":"63","author":"Lim","year":"2018","journal-title":"Scott Med J"},{"key":"B13","doi-asserted-by":"publisher","first-page":"778","DOI":"10.1093\/cid\/cix881","article-title":"Understanding the promises and hurdles of metagenomic next-generation sequencing as a diagnostic tool for infectious diseases.","volume":"66","year":"2018","journal-title":"Clin Infect Dis"},{"key":"B14","doi-asserted-by":"publisher","first-page":"10","DOI":"10.1186\/1471-2334-14-10","article-title":"Multivariate analysis of prognostic factors in patients with pulmonary actinomycosis","volume":"14","author":"Park","year":"2014","journal-title":"BMC Infect Dis"},{"key":"B15","doi-asserted-by":"publisher","first-page":"80","DOI":"10.4103\/1817-1737.62470","article-title":"Treatment of thoracic actinomycosis: a retrospective analysis of 40 patients","volume":"5","author":"Song","year":"2010","journal-title":"Ann Thorac Med"},{"key":"B16","doi-asserted-by":"publisher","first-page":"33","DOI":"10.3760\/cma.j.cn112140-20200430-00453","article-title":"Pulmonary actinomycosis in children: a case report and literature review","volume":"59","author":"Huang","year":"2021","journal-title":"Zhonghua Er Ke Za Zhi"},{"key":"B17","doi-asserted-by":"publisher","first-page":"955554","DOI":"10.3389\/fped.2022.955554","article-title":"Pediatric pulmonary actinomycosis: a misdiagnosed case report","volume":"10","author":"Zhao","year":"2022","journal-title":"Front Pediatr"},{"key":"B18","doi-asserted-by":"publisher","first-page":"2211","DOI":"10.1378\/chest.128.4.2211","article-title":"Optimal duration of IV and oral antibiotics in the treatment of thoracic actinomycosis","volume":"128","author":"Choi","year":"2005","journal-title":"Chest"},{"key":"B19","first-page":"346","article-title":"CT Findings of paediatric thoracic actinomycosis; report of four cases","volume":"91","author":"Ng","year":"1992","journal-title":"J Formos Med Assoc"}],"container-title":["Frontiers in Pediatrics"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fped.2026.1882250\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T05:37:12Z","timestamp":1783316232000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fped.2026.1882250\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,6]]},"references-count":19,"alternative-id":["10.3389\/fped.2026.1882250"],"URL":"https:\/\/doi.org\/10.3389\/fped.2026.1882250","relation":{},"ISSN":["2296-2360"],"issn-type":[{"value":"2296-2360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,6]]},"article-number":"1882250"}}