Pericallosal lipoma

13-year-old male with a pericallosal lipoma and agenesis of the corpus callosum. Sagittal T1- (A), fat-saturated (fs) T2-weighted (B), and transverse axial FLAIR (C) and fsT2-weighted (D) MRIs show a T1/FLAIR hyperintense, midline mass that is uniformly hypointense on fsT2-weighted images. Note the absent corpus callosum on sagittal images and widely-spaced ventricles oriented in parallel on transverse axial MRIs. Cranial lipoma is a nonneoplastic, congenital malformation consisting of adipose tissue and is therefore isointense with fat (note similar signal intensity of lipoma and subcutaneous fat) on all pulse sequences.