Aggressive osteoblastoma involving the craniovertebral junction: A case report and review of literature
The present case report is about a 34-year-old gentleman who presented with a painful swelling behind the angle of left mandible of 5 months duration. He also complained of change in character of voice, dysphagia and weakness of left upper limb for 3 months prior to admission.\nOn neurologic examination, he had IX, X and XI cranial nerve palsy on the left side. There was a 3.5 cm × 3.0 cm bony hard swelling underneath the angle of left mandible leading to obliteration of post auricular groove. It was extremely tender. On examination of the oral cavity, the swelling was bulging into the tonsillar fossa and compressing the palatal arches.\nSince, the mass was palpable externally, fine-needle aspiration was attempted pre-operatively (twice) and on both occasions, but it was found to be inconclusive.\nThe axial and reformatted sagittal computed tomography showed a large expansile and destructive bony lesion involving the foramen magnum on the left side from lower clivus up to the axis. There were calcifications seen within the tumor. Thin sclerotic rim was visible around most of the periphery of the lesion [Figure –]. The lesion had involved the lateral masses and part of anterior and posterior elements of upper 2 cervical vertebrae.\nMagnetic resonance imaging showed a heterogenous mass (size approximately 5.3 cm × 6.2 cm × 5.5 cm) with strong post contrast enhancement. The lesion was displacing left internal carotid artery peripherally causing mild compression and had involved the left vertebral artery, the oblique part of V3 segment [Figure –].\nWith pre-operative impression of a high grade bony lesion, the patient was planned for surgical decompression of the mass through left sided far lateral approach. At surgery, near total excision of the tumor was achieved, deliberately leaving a thin rim of tumor tissue attached to posterior pharyngeal wall to prevent opening the oral cavity [Figure and ]. The tumor was very vascular and bled profusely. Occipito-cervical fusion was also done. The patient recovered uneventfully after surgery. Histopathological evaluation of the resected tissue showed epithelioid osteoblasts lining the bony trabeculae separated from the thin walled vessels by the osteoclastic giant cells. Mitotic figures were also seen. Hence, a pathological diagnosis of AO was made [Figure and ]. The patient was referred to radiotherapy for residual lesion. At 5 months follow-up, the patient was doing well.