Imaging Features of Skull Base Tumors with Special Attention to the Central Skull Base

Purpose: The skull base is an anatomically complex area where a variety of pathologic processes can develop. The purpose of this exhibit is to provide the non-radiologist with an easily accessible review of the computed tomography (CT) and magnetic resonance (MR) characteristics of skull base lesions, with special attention to the central skull base.

Approach/Discussion: This exhibit will begin with a review of skull base anatomy as it appears on cross-sectional imaging. The bulk of the exhibit will use a case-based format to discuss the imaging appearances of various lesions involving the skull base. CT and MR are used in complementary fashion in the evaluation of skull base lesions. Specifically, CT is excellent for assessing the extent of bony involvement, whereas MR is primarily used to more definitively characterize soft tissue components of a mass.

Common central skull base masses to be reviewed include pituitary macroadenoma, aneurysm, arachnoid cyst, epidermoid/dermoid, craniopharyngioma, hypothalamic glioma/hamartoma, metastasis, meningioma, and masses of the petrous apex. Rarer lesions to be discussed include pseudotumor, chordoma/chondrosarcoma, neuroblastoma, giant cell tumor, and fungal infection, among others. Comment will be made on key diagnostic clues and pitfalls, and imaging features of particular importance for surgical planning.

This review will also include “do not touch” lesion mimics, including trapped fluid within the petrous apex, asymmetric marrow/pneumatization of the petrous apex, and petrous apex cephalocele.

Finally, the reader will learn a systematic approach to characterizing complex lesions. Emphasis will be placed on identifying (1) lesion location and extension to critical adjacent anatomy, (2) typical imaging features, and (3) imaging technique.

Conclusion: The skull base is host to a wide range of pathologic processes. This imaging-based educational exhibit provides the non-radiologist with a review of CT and MR characteristics of skull base lesions as well as a systematic approach for characterizing complex lesions.