Inflammatory myofibroblastic tumors in children: clinicopathological characteristics and treatment outcomes

Abstract Background Pediatric inflammatory myofibroblastic tumors (IMTs) are rare soft tissue neoplasms. We present a 15-year Egyptian study on IMTs in children, detailing clinicopathological features, management strategies, and outcomes. This retrospective analysis included all children with histologically confirmed IMTs treated at our tertiary center between 2009 and 2024. Data collected included demographic and clinical characteristics, tumor location, imaging findings, surgical and systemic treatments, and survival outcomes. Results A total of 38 patients were enrolled, with a median age of 8.5 years (range: 3 months-17 years). Abdominopelvic tumors were the most common, observed in 27 patients (71%), including 13 with urinary bladder involvement. Thoracic tumors were identified in 8 patients (21%), and head and neck tumors in 3 patients (8%). The median largest tumor diameter was 7 cm (range: 3–15 cm). Anaplastic lymphoma kinase (ALK) gene expression was assessed in 25 patients, of whom 17 tested positive (68%). Primary surgical resection was performed in 29 patients (76%), and 4 of these received adjuvant therapy (2 received ALK inhibitors and 2 received chemotherapy and steroids). The remaining 9 patients (24%) underwent delayed surgery following neoadjuvant therapy. After a median follow-up of 90 months, local recurrence or progression occurred in four patients—all with abdominal IMTs and all initially managed with incomplete resections. One patient with brain metastases died despite salvage therapies. The 5-year overall survival was 97% (95% CI: 91.4%–99.2%), and the 5-year event-free survival was 86% (95% CI: 76.6%–91.3%). Tumor location had no significant impact on recurrence ( p = 0.402). However, incomplete surgical margins (R1 and R2) were significantly associated with an increased risk of recurrence/progression compared to complete (R0) resections (p-value = 0.019 and <0.001, respectively). Conclusions Surgical resection leads to favorable outcomes in all children with IMTs. Neoadjuvant therapies are crucial in patients with initially unresectable tumors. Achieving complete tumor resection remains the cornerstone of long-term event-free survival. Meticulous follow-up is essential for early detection and treatment of tumor recurrence.