Venous malformations invade the median nerve: A rare case and surgical management

Abstract

• Intraneural venous malformation may mimic schwannoma of the median nerve. • Sclerotherapy is potentially neurotoxic in intraneural locations. • Nerve-preserving interfascicular surgery provides excellent functional outcome. Intraneural venous malformation of the median nerve is an exceptionally rare condition that may mimic nerve sheath tumors. Preoperative diagnosis is challenging and optimal management remains controversial because radical excision risks neurological deficit, while sclerotherapy is potentially neurotoxic. A 13-year-old girl presented with a painful bluish mass of the distal palmar forearm associated with intermittent thumb paresthesia. Imaging demonstrated a low-flow venous malformation in close relationship with the median nerve. After multidisciplinary discussion, sclerotherapy was rejected due to suspected intraneural extension. Surgical exploration revealed venous channels infiltrating the nerve fascicles. A nerve-preserving interfascicular microsurgical debulking was performed rather than radical excision. The postoperative course was uneventful with no motor or sensory deficit. At three-year follow-up, a small stable residual lesion persisted without symptoms or progression. Intraneural venous malformations require individualized management. When nerve infiltration is present, functional preservation should prevail over radical resection, and sclerotherapy should be avoided because of potential neurotoxicity.