Leiomyoma of the Forehead

165 Leiomyoma is a benign proliferation of smooth muscle cells that may be found in various anatomical locations. Leiomyoma of the uterus is the most common, and there have been a few case reports of extra-uterine leiomyomas including on the hand, foot, esophagus, trachea, heart, and even in vessels. However, there have been no reports of leiomyoma of the frontalis muscle. We present a case of leiomyoma of the frontalis muscle that was excised using an endoscopic method. A 5-year-old boy was referred to our hospital with a palpable mass on his left forehead. It was first observed when he was 4-year-old (Fig. 1). Computed tomography revealed a nonspecific soft tissue lesion on his left forehead. Except for the lesion, there were no other abnormalities on his skull, ventricle, or brain parenchyma. The patient revisited the hospital 1 year after the first visit because the size of the mass had increased. The mass was 1 cm in diameter and non-tender, and the patient did not experience any discomfort. The mass was somewhat firm and movable. There were no clinical signs suggesting an inflammatory lesion such as an epidermal cyst. We initially suspected a lipoma. The mass was excised using an endoscopic approach under general anesthesia. Anesthesia and hydrodissection were performed by injecting an excessive amount of lidocaine mixed with epinephrine between the galea and the periosteum, to ease the performance of the dissection. Two incisions of 1.5 cm in length were made 1 cm behind the hairline for less visible scarring and to create the shortest distance and easiest approach to the lesion. The endoscope with a retractor and other surgical instruments were inserted through these incisions. We dissected the muscle using a Freer elevator with palpation (Fig. 2). The mass was identified intramuscularly, and was completely excised without any remnant lesion. It was solid with a fibrous capsule (Fig. 3). Pathologically, the mass showed the characteristics of a leiomyoma, and a definite diagnosis was confirmed based on the immunohistochemistry showing desmin Leiomyoma of the Forehead