Carpal tunnel syndrome caused by a vascular malformation in a 48-year-old woman

INTRODUCTION: Vascular malformation can present as nerve compression syndrome in middle age due to slow lesion growth, after first appearing in childhood. In a case of vascular malformation involving the peripheral nerve, surgical resection may cause uncontrollable hemorrhage and further nerve compression. Therefore, a more conservative approach is needed in such cases. CASE PRESENTATION: A 48-year-old woman complained of pain and paresthesia of the fingers, and was diagnosed with a large vascular malformation expanding from the proximal forearm to the palm on MRI. Because of the size of the lesion and involvement of soft tissue, resection had a risk of major hemorrhage and incomplete removal. Thus, carpal tunnel release was performed as a less invasive procedure, and was effective for reducing pain while avoiding the risks associated with resection. DISCUSSION: Our case indicates that a vascular lesion is a possible cause of nerve compression in the carpal tunnel. Finger numbness and pain were caused by this nerve compression, but the lesion itself was not painful. The median nerve was separate from the venous structure, and the case was diagnosed as an extraneural type. CONCLUSION: Symptoms that develop in middle age due to an extraneural vascular malformation in the carpal tunnel can be treated successfully using carpal tunnel release, instead of more invasive resection of the lesion.