A 55-year-old man with a previous diagnosis of chronic otomastoiditis in his left ear was admitted to our hospital with complaints of a 1-month history of progressive posterior cervicalgia. He also presented with dysphasia and repetitive aspirations three months before his admission. His neurologic examination revealed diffuse paravertebral tenderness, neck motion limitation to the left side, left facial nerve palsy (House-Brackmann grade 4) and severe ipsilateral hearing loss. The findings of a cerebellar function test were unremarkable. There was no previous history of surgical operation. Due to the progressive and severe nature of his symptoms, he underwent magnetic resonance imaging (MRI) of the brain with a 1.5T MR unit. MRI imaging disclosed a homogenously enhancing solid mass occupying the clivus, extending posterolaterally into the epidural space of posterior fossa beyond temporal bone, and anteriorly to prevertebral space at cervicomedullary junction (Fig. 1). Its intracranial portion occupying the posterior fossa engulfed intraosseous segment of left intra cranial artery (ICA). There was no connection between the mass and the sellar or suprasellar regions. The size and location of the pituitary gland were unremarkable. It was mainly isointense to the brain cortex on both T1-weighted and T2-weighted images (Fig. 1). On high resolution bone algorithm CT images revealed that permeative bone destruction was excessively demonstrated in clivus, occipital condyle, petrous and mastoid portions of left temporal bone (Fig. 2). However, there was no calcification or cystic change observed within the lesion. Carotid and vertebral angiography revealed that the tumor was avascular and moved left vertebral artery toward the medial direction (Fig. 2). The differential diagnosis included chordoma, sarcoma and metastasis of skull base.

The patient underwent resection of the mass via suboccipital craniectomy using the left transcondylar approach and C1 hemilaminectomy. The tumor mass began to bulge out when the occipital condyle was drilled. The intracranial segment of the vertebral artery was displaced posteriorly and medially by the tumor mass. The vertebral artery adhered to the surrounding soft tissue and tumor mass itself. The glossopharyngeal, vagal and hypoglossal nerves were intermingled with the tumor mass, which was rubbery and of hard consistency and moderate vascularity. A dural incision was made after the tumor mass was partially removed, but there were no signs of a definite tumor in the intracranial space. The pathological results demonstrated irregular nests of multistratified squamous cells with peripheral palisading of the nuclei and keratin (Fig. 3).

His symptoms, however, were not improved. Then, the patient was referred for radiotherapy at a dose of 72 Gy (40 fractions), however, the radiation therapy was stopped after the administration of the 36 Gy dose because of deterioration of his general condition. One 1 month later, he died of aggravation of aspiration pneumonia which did not respond to antibiotic treatment.