Right frontotemporoparietal abnormal marrow signal with extensive periosteal reaction of the outer table (hair-on end appearance), and an overlying subgaleal soft tissue component that enhances peripherally, surrounding by an edematous scalp. The permeative process extends to the inner table of the skull, deep to which there is an extraaxial mass. The extraaxial lesion is heterogenously enhancing, with enhancement of the overlying meninges extending anteriorly and posteriorly. The extraaxial component demonstrates restricted diffusion. No blood products on EPI images. Mild mass effect of the extraaxial lesion compressing the underlying brain, partially effacing the sulci with minimal midline shift. No other abnormalities was identified.
Conclusion:
Right skull mass lesion as described centered on the skull bone with subgaleal and extraaxial components. Appearance is that of a neoplastic processes, including sarcoma of bone, and less likely metastatic deposits. Because of the heterogenous enhancement, meningioma including en plaque or atypical is considered less likely but remains a possibility.