Anterolateral thigh flaps (ALT flaps) are useful for soft tissue reconstruction in the treatment of severe limb trauma. Many anatomical variations of the vascular pedicle of ALT flaps require skilled flap elevation. Although there have been many reports on anatomical variations of the vascular pedicle of ALT flaps, those on the anatomical anomalies of the venae comitantes of the perforator are limited. We report a case of an ALT flap with an anatomical anomaly of the venae comitantes of the perforator. The ALT flap was performed for a patient with a traumatic soft tissue defect in the lower extremity. Due to anatomical anomaly of the venae comitantes of the perforator, the perforating artery was ligated during flap elevation. The ligated perforator artery was anastomosed microscopically to the distal part of the descending branch of the lateral circumflex femoral artery to secure circulation of the ALT flap. The ALT flap survived without complications and the postoperative course was uneventful.
