The pathologic diagnosis was lymphoma which is usually hyperdense on CT; helpful in differentiating it from other malignancies.

The main differential diagnosis for a corpus callosal mass includes:

• lymphoma (PCNSL)
• glioblastoma multiforme (butterfly glioma)
• less frequently encountered
  • tumefactive demyelination
  • radiation necrosis
  • evolving hemorrhage / contusion / infarct

Lipoma of the corpus callosum very rarely occurs, but the diagnosis is usually straight-forward since there is an obvious fat density.