Cervical ecchordosis physaliphora: CT and MR features.

We report a case of cervical ecchordosis physaliphora in an elderly man who presented with hemihypoaesthesia and contralateral hemiparesis. MRI showed a well defined, non-enhancing extradural mass lesion on the dorsal surface of the odontoid process of the axis. The lesion was of intermediate signal intensity on T1 weighted images and of low signal intensity on T2 weighted images. CT showed a small bony defect on the adjacent cortex of the odontoid process. Recognition of the imaging features of ecchordosis physaliphora is helpful in suggesting the diagnosis and differentiating the lesion from chordoma.