2026 Volume 62 Issue 6 Pages 1064-1073
Desmoid-type fibromatosis is a rare fibroblastic tumor without metastatic potential but with marked local aggressiveness. We report a case of a 14-year-old boy who had experienced dyspnea for 8 months and had been treated for bronchial asthma without improvement. Contrast-enhanced computed tomography revealed a 20-cm mass occupying the right thoracic cavity, with leftward mediastinal shift, marked narrowing of the right main bronchus, and collapse of the right lung. Core needle biopsy confirmed desmoid-type fibromatosis. As his respiratory status worsened and the risk of asphyxia became imminent, the patient was managed as an oncologic emergency. Extracorporeal circulatory support was established under awake conditions, followed by surgery. Approximately 80% of the tumor was removed while preserving the involved vital structures, resulting in relief of the airway obstruction. Postoperatively, pazopanib induced slight shrinkage of the residual tumor, but treatment was discontinued because wound dehiscence developed as a suspected adverse effect, and therapy was switched to methotrexate/vinblastine. Pazopanib was resumed 11 months after surgery, and the patient has remained free from regrowth for 47 months postoperatively. In addition, we conducted a literature review of 95 pediatric cases of desmoid-type fibromatosis reported in Japan.
