Plexiform neurofibroma at the thoracic inlet has rarely been reported and to our knowledge, the use of a temporary middle claviculectomy approach for thoracic inlet tumors has never been reported. We report a case of plexiform neurofibroma of the first intercostal nerve resected using a temporary claviculectomy approach. An abnormal shadow detected radiographically in a 16-year-old boy led to a diagnosis of neurofibromatosis 1 (NF-1) with a chest wall tumor at the thoracic inlet. The patient underwent resection of the tumor with the right first rib. The resected clavicle was reapproximated with a plate and postoperative shoulder function was satisfactory. The tumor was diagnosed pathologically as a plexiform neurofibroma and the patient's postoperative course was uneventful. The temporary middle claviculectomy approach provides excellent exposure of the subclavian vessels and brachial plexus before resection of the tumor. We recommend this approach for tumors of the anterior thoracic inlet.