Primary Intraosseous Hemangioma in the Frontal Bone

Intraosseous hemangioma is a rare bone tumor accounting for 0.7% to 1.0% of all bone tumors. It can occur at all ages but is most common in the fourth and fifth decades of life and has a female preponderance (3:1) [1]. Intraosseous hemangiomas are usually found in the vertebral column and rarely seen in the calvarium. Among the calvarial bones, the parietal bone is the most commonly involved, followed by the frontal bone and less frequently by the occipital and temporal bones [2]. The pathogenesis is still unknown but a history of trauma seems to be related in some cases reported in the literature [3]. A 39-year-old woman presented with a swelling on the left forehead, which had been slowly enlarging for one year. She had a history of minor trauma on her forehead one-and-a-half years earlier and she seemed to believe that her swelling was related to her previous head trauma. Other medical history and a review of systems were insignificant. The mass was bony hard, tender, and measured approximately 3×3 cm. A plain skull X-ray showed a radiolucent lesion on the frontal bone and a bone window computed tomography (CT) scan demonstrated a 3×3.5×1.5 cm intradiploic osteolytic mass adjacent to the left frontal sinus wall and the orbital roof (Fig. 1). The mass was interpreted as a fibrous dysplasia by a radiologist. Under general endotracheal anesthesia, a bicoronal incision was made, and the mass was exposed. The mass had a hemorrhagic feature, which contained a cluster of small vessels replacing the bony structure (Fig. 2). The mass expanded externally and intracranially, and the inner surface of the mass had loosely adhered to the dura mater. The mass, along with 0.5 cm of normal bone margin, was removed en bloc by craniotome. The frontal sinus wall and orbital roof were preserved intact after the removal of the mass. The bony defect was reconstructed with two pieces of split calvarial bone harvested from the right parietal bone (Fig. 3). A histologic examination of the Fig. 1. Preoperative computed tomography (CT) scan. A bone window CT scan demonstrated a 3×3.5×1.5 cm intradiploic osteolytic mass adjacent to the left frontal sinus wall and the orbital roof.