Nerve-sparing surgical management of pediatric desmoid tumors involving major peripheral nerves: A case series.

Introduction: Desmoid tumors (DTs) are rare, locally aggressive fibroblastic neoplasms that, despite lacking metastatic potential, may cause significant morbidity due to infiltrative growth and local recurrence. Pediatric cases involving major peripheral nerves are exceptional and present unique diagnostic and therapeutic challenges. Research question: This study aimed to characterize pediatric DTs with peripheral nerve involvement and to evaluate outcomes of nerve-sparing surgical strategies focused on oncologic control and functional preservation. Material and methods: A retrospective case series of seven pediatric patients (6-19 years) with histologically confirmed DTs involving major peripheral nerves were analyzed. All patients underwent microsurgical resection at the Division of Neurosurgery, Gaffrée and Guinle University Hospital (UNIRIO) between 2010 and 2024. Clinical, radiological, and surgical variables were assessed, including motor function, pain (VAS), margin status, recurrence, and multimodal treatment strategies. Results: Tumors affected the lower limbs: fibular (n = 3), sciatic (n = 3), and tibial nerve (n = 1). Mean tumor size was 15.3 ± 4.1 cm. R0 resection was achieved in four patients (57.1%), R1 in one (14.3%) and R2 in two (28.6%) due to nerve encasement. Motor function was fully preserved postoperatively (M5), and pain improved markedly (median VAS 8 to 0-2). One patient (14.3%) developed local recurrence and required repeat surgical excision. Discussion and conclusion: Pediatric DTs involving peripheral nerves are rare, typically sporadic, and require individualized management. Nerve-sparing surgery achieved local control and pain relief without functional compromise. Prognoses depend more on tumor biology and anatomical constraints than to margin status, underscoring the value of function-preserving and long-term multidisciplinary follow-up.