Incongruent radiographic indication of calvarial metastatic diploic space invasion with absent histologic findings in a patient with basal cell carcinoma of the scalp.

Surgeons should be wary of diploic space changes in the absence of cortical erosion demonstrated in MRI as it may not explicitly indicate tumor invasion. Biopsy of the diploe is necessary in such cases to determine the surgical course and to avoid morbidity associated with calvarium removal.