Presentation
Sudden onset headache. No focal neurology.
Patient Data
There is a curvilinear fat density lesion which lies immediately superior to the corpus callosum consistent with a pericallosal lipoma.
Case Discussion
The magnified sagittal images enable measurement of the Hounsfield units and reveal the lesion to be of fat density (-50 HU) and not the density of air, as the initial appearances suggested possible pneumocephalus.
Furthermore, the configuration of the fat can be seen on the sagittal images to lie both above the corpus callosum and posteriorly underneath the splenium of the corpus callosum, which excludes air, as this would rise dependently.