声門下炎症性筋線維芽細胞腫：小児患者における稀な症例報告

Background: Inflammatory myofibroblastic tumour (IMT) of the pediatric laryngotracheal complex is exceedingly rare, with fewer than nine subglottic IMT cases reported in the literature up to 2025. We present an additional case and highlight the importance of early recognition. Case presentation: A previously healthy 10-year-old boy presented with a 3-week history of progressive dyspnea on exertion and nocturnal biphasic stridor, initially mislabelled as refractory asthma. Contrast-enhanced CT revealed a left-sided subglottic soft-tissue mass that reduced the airway lumen to 2.7 mm, while rigid bronchoscopy confirmed an 80% occlusion caused by a 10 mm submucosal lesion spanning the cricoid and first tracheal ring. After emergent tracheostomy at the referring institution, he underwent lesion resection and simultaneous decannulation. Histopathology demonstrated spindle-cell proliferation within a myxoid inflammatory stroma; immunohistochemistry was ALK-1-positive, confirming IMT. Post-operative bronchoscopy on day seven showed a widely patent airway. Five years later the child remains asymptomatic and oxygen-independent, with no radiological or endoscopic evidence of recurrence. Conclusion: This case reinforces that persistent pediatric stridor mandates prompt endoscopic evaluation and that complete surgical excision remains the gold-standard therapy for airway IMT. Given the tumour's intermediate malignant potential and a reported 18-40% recurrence rate when margins are positive, meticulous long-term surveillance is indispensable, and ALK-directed therapy should be considered when resection is not feasible. Timely diagnosis and radical local therapy can avert prolonged tracheostomy and enrich the scant literature on pediatric subglottic IMT.