Imaging Findings of the Pediatric Clivus Chordomas

Abstract

Both computed tomography (CT) and magnetic resonance imaging (MR) are required for evaluation of clivus chordomas due to anatomic complexity of the skull base, bone involvement, and the proximity of these tumors to many important neural and vascular structures. They have complementary roles in the evaluation of chordoma. The excellent imaging capabilities of MRI and CT allow precise delineation of the clivus chordoma with respect to volume and relation to adjacent structures. The pretreatment goal of the imaging of clivus chordomas is to delineate the tumor margins, adjacent cranial nerves, and vascular structures. The posttreatment goal of the imaging is to define the extent of the surgery; to guide for the additional therapy, if needed; and to differentiate the recurrence from the post-therapy changes. The classical radiologic feature of the clivus chordoma is a destructive soft-tissue mass with calcification due to sequestra from bone destruction and/or dystrophic mineralization (Fig. 1a-c). Intracranial chordomas most often originate from the spheno-occipital synchondrosis of the clivus and located in the midline (Fig. 2). However, it presents with more or less marked symmetric or asymmetric lateral extension (Fig. 3a-j). Furthermore, it may extend into the cavernous sinus, sphenoid sinus, and nasopharynx. But the site of origin is usually along the caudal margin of the clivus, and extension through the foramen magnum is common in younger children (Fig. 4a, b). But it may also be originated from the cranial margin of the clivus (Fig. 5a).