Cerebellopontine Angle Lipoma

cerebellopontine angle lipoma

This small CPA lipoma elegantly demonstrates the facial nerve and vestibulocochlear nerve coursing through it. (see here for annotated image). There is an association with intravestibular lipomas.

Intracranial lipomas are not tumours as such, but rather a result of “abnormal differentiation of embryologic meninx primitiva“. From this meninx primitiva cranial nerves, the arachnoid layer and pericallosal arteries form, explaining why often these structures are closely associated with intracranial lipomas. Additionally, adjacent underdevelopment of brain structures is frequently encountered: e.g. agenesis of the corpus callosum, underdevelopment of the inferior colliculus.

For a differential of cerebellopontine masses that are high on T1WI please visit Radiopaedia.org here.

References:
1. L.A. Loevner. Brain Imaging – Case review
2. StatDx.com
3. Dahlena, R. et al. CT and MR Imaging Characteristics of Intravestibular Lipoma. American Journal of Neuroradiology 23:1413-1417, September 2002

Credit: Dr Frank Gaillard