Indian Journal of Neurosurgery Vol. 1 ■ Issue 1 ■ January-March 2012 86 Access this article online Quick Response Code: Website: www.ijns.in DOI: 10.4103/2277-9167.94380 CASE REPORT outlined a faintly calcified mass in the anterior cranial fossa [Figure 1a]. No bony erosion could be appreciated. CT and MRI of brain [Figures 1b-f] showed a large extra- axial, solid, calcified, subfrontal mass extending into the nose and displacing the eyeballs. There was no cerebral edema or hydrocephalus. Bifrontal craniotomy was done which revealed solid, friable, vascular tumor in the ethmoidal region causing upward displacement of basal dura. Tumor could be excised by curetting and suction, and the intranasal portion was removed by endoscopy assistance. Anterior cranial fossa floor was covered with pericranial flap, bone flap was anchored back and scalp was closed with subgaleal drain. Postoperative period was uneventful and he was discharged on the seventh postoperative day. He remains asymptomatic (barring anosmia) over the past one year. Histopathology sections (H and E) showed randomly interconnected and separate trabeculae of osteoid and woven bone prominently rimmed by osteoblasts. The stroma around the trabeculae was densely populated by fibroblasts and contained many dilated and congested vessels [Figure 2]. Occasional osteoclastic giant cells were seen. No granuloma or inflammatory infiltrate were noted. Based on the clinical profile, imaging appearances and histopathological picture, a diagnosis of osteoblastoma was made. DISCuSSION Osteoblastoma is an uncommon bone tumor, representing nearly 3% of all benign bone tumors. [4] Osteoblastoma is Address for correspondence: Brig Harjinder S. Bhatoe, Department of Neurosurgery, Command Hospital (SC) and AFMC, Pune - 411 040, Maharashtra, India. E-mail: hsbhatoe@gmail.com INTrODuCTION Osteoblastoma is an uncommon tumor that was first described in 1956 in separate reports by Jaffe and Lichtenstein. [1,2] The neoplasm forms osteoid tissue, and is pathologically distinct from ossifying fibroma, classical osteoid osteoma and osteoma. It commonly involves the spine, long bones and small bones of hands and feet. Less often, it involves the calvaria, patella, ribs and scapula. Skull base involvement is rare, and has been reported with involvement of orbit, [2] ethmoids [Table 1], sphenoid sinus. [3] There are only eight well-documented cases reported that involved or arose from the ethmoid region and extended into the nasal cavity [Table 1]. CASe rePOrT A 22-year-old male was admitted with six-month-history of dull frontal headache and facial pain, feeling of nasal obstruction and mild prominence of both eyeballs. There was no history of nasal discharge, epistaxis, visual dimness or any limb weakness. Clinical evaluation revealed mild proptosis on both sides and anosmia. Anterior rhinoscopy revealed a firm nasal mass visible from both sides. The mass did not bleed on touch. Plain radiograph of the skull ABSTRACT Osteoblastoma is a rare, benign bony tumor of skull base. We report one such case. Clinical record. We reviewed the record of a 21-year-old-male, who presented with nasal obstructon and proptosis. The tumor had formed a large mass that displaced the frontal lobes, the orbits and projected into the nasal cavity. Imaging revealed a calcifed nodular expansile lesion. The tumor could be excised near-total by bifrontal craniotomy combined with endonasal approach. Histopathology was confrmatory of osteoblastoma. The patent was discharged on the seventh postoperatve day and is now on follow-up. Osteoblastoma is a rare tumor of the frontoethmoid region. Surgery requires metculous planning and team approach. Key words: Bone tumor, craniofacial, ethmoids, osteoblastoma, skull base Osteoblastoma of the ethmoid Harjinder S. Bhatoe, M. D. Venkatesh 1 , Prabal Deb 2 Departments of Neurosurgery & 1 ENT and 2 Pathology, Armed Forces Medical College and Command Hospital (SC), Pune, Maharashtra, India This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.