思春期における坐骨神経の孤発性びまん型巨大神経線維腫：稀な症例

Giant solitary neurofibromas involving deep peripheral nerves, particularly the sciatic nerve, are exceptionally rare in pediatric patients and pose unique diagnostic and surgical challenges. They often remain asymptomatic due to their deep intermuscular location, which delays detection until significant growth occurs. We report a 13-year-old male with a painless posterior thigh swelling, incidentally noticed while playing. MRI revealed a 12.8 × 6.6 × 3.8 cm lobulated intermuscular mass along the sciatic nerve. Tru-cut biopsy suggested a cellular neurofibroma. The patient underwent function-preserving excision under microscopic magnification, with careful dissection of the tumor from individual sciatic nerve fascicles. Intraoperative neurophysiological monitoring (IONM) was not available, highlighting the challenges of ensuring nerve preservation without real-time feedback. Postoperatively, transient foot drop occurred but resolved completely with physiotherapy. Histopathology confirmed a diffuse-type cellular neurofibroma with patchy S100 and SOX10 positivity, focal CD34 expression, and low Ki-67, supporting a benign profile. This case underscores the importance of meticulous surgical technique, the potential value of IONM, and vigilant postoperative care in achieving optimal outcomes for deep-seated pediatric neurofibromas.