MRI and CT findings of the giant cell tumors of the skull; five cases and a review of the literature.

PURPOSE: To investigate CT and MR findings of giant cell tumors (GCTs) of the skull, an unusual site for such tumors.
MATERIALS AND METHODS: CT and MR features of five histologically proven giant cell tumors of the skull were retrospectively reviewed. We also reviewed 22 cases in the literature that included MR or CT findings.
RESULTS: Three of the tumors originated from the temporal bone with predominantly medial extension, and the other two were centered in the body of the sphenoid bone and featured symmetrical soft tissue extension. CT images with bone window settings showed reactive bone changes for all three tumors of the temporal bone, suggesting slow growth for example, an expanded intradiploic space, expansive remodelling and development of foci of pressure erosion. GCTs of the sphenoid bone showed purely osteolytic changes without remodelling. Although the MR signals and enhancement patterns varied, all the tumors of the temporal bone had a markedly low intensity area on T2-weighted images, which was not seen in the tumors of the sphenoid bone. The findings for our cases generally corresponded to those reported in the literature.
CONCLUSION: Giant cell tumors of the skull have two preferential sites and may have characteristic tendencies as to their extent. Bone changes and MR signals appear to show differences between the two sites.