AP view of skull xp (a) showing the bony defect of the left occipital lesion. Bone image CT at the level of the subcutaneous mass (b) demonstrating the bony defect of the left occipital bone without a change in the intraaxial lesion. The skull surface of the defective part was swollen. Axial T1-weighted MRI with contrast medium (c) showing a cystic change corresponding to the bony defect and partial enhancement around the cystic change. 99mTc-HMDP bone scintigraphy (d) showing accumulation of tracer in the part of the bone cyst corresponding to the strongly enhanced lesion found on MRI. Head DSA study (e, lateral view) demonstrating no abnormal vessels, including tumor feeder or aneurysmal changes.
