{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T06:15:56Z","timestamp":1788156956316,"version":"build-2803163510"},"reference-count":25,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T00:00:00Z","timestamp":1788134400000},"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. Immunol."],"abstract":"<jats:p>Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm, approximately 50% of which harbor ALK rearrangements. ALK-negative gastric IMT (G-IMT) in pediatric patients is exceptionally rare and poorly characterized. We report a 6-year-old male with fever, melena, and severe anemia (Hb 30 g\/L). Imaging revealed a gastric fundus mass, and subtotal gastrectomy confirmed IMT with dense plasma-cell infiltrate and negative ALK immunostaining. We performed single-cell RNA sequencing on tumor and paired adjacent non-tumor tissue (14,103 cells). CellChat analysis inferred prominent CXCL12-CXCR4 communication between neoplastic myofibroblasts and immune cells. Macrophage subclustering identified an S100A9-high inflammatory tumor-associated macrophage state, and pseudotime analysis placed this state along a continuous transcriptional ordering with resident-like macrophages. To our knowledge, this is the first single-cell transcriptomic characterization of pediatric ALK-negative G-IMT and provides hypothesis-generating insight into its inflammatory microenvironment.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1855526","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T05:41:05Z","timestamp":1788154865000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Single-cell transcriptomic profiling of a pediatric ALK-negative gastric inflammatory myofibroblastic tumor"],"prefix":"10.3389","volume":"17","author":[{"given":"Jusen","family":"Nong","sequence":"first","affiliation":[{"name":"Department of Pediatric Surgery, The First Affiliated Hospital of Guangxi Medical University","place":["Nanning, Guangxi Zhuang Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weikun","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Pediatric Surgery, The First Affiliated Hospital of Guangxi Medical University","place":["Nanning, Guangxi Zhuang Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Shi","sequence":"additional","affiliation":[{"name":"Department of Pediatric Surgery, The First Affiliated Hospital of Guangxi Medical University","place":["Nanning, Guangxi Zhuang Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,31]]},"reference":[{"key":"B1","volume-title":"WHO Classification of Tumors: Soft Tissue and Bone Tumors","author":"Wcote","year":"2020"},{"key":"B2","volume-title":"Diagnostic Pathology: Soft Tissue Tumors E-Book","author":"Lindberg","year":"2024"},{"key":"B3","doi-asserted-by":"publisher","first-page":"102","DOI":"10.1007\/s12032-018-1161-0","article-title":"Clinical and histopathologic correlates and management strategies for inflammatory myofibroblastic tumor of the lung. 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