Brain lipomas are not hamartomas or true neoplasms. They are comgenital malformations representing persistence and maldifferentiation of the mennix primativa ( a mesenchymal neural crest derivative which forms part of the dura, arachnoid, subarachnoid cisterns, and the pia). Greater than 50% are associated with other specific brain malformations. The incidence is rare representing only .1-.5% of brain tumors. There are 2 main subtypes
Tubulonodular- Large, bulky, round or cylindrical mass with high incidence of corpus callosum dysgenesis, frontal lobe anomalies and cephaloceles.
Curvilinear- Thin lesions which curve around the splenium. 80-95% of the time the lipomas are midline. 50% are dorsal and pericallosal. Other locations include the quadrigeminal, ambient, suprasellar and cerebello-pontine cisterns. A lipoma can be associated with agenesis or dysgenesis of the corpus callosum
Tubulonodular- Large, bulky, round or cylindrical mass with high incidence of corpus callosum dysgenesis, frontal lobe anomalies and cephaloceles.
Curvilinear- Thin lesions which curve around the splenium. 80-95% of the time the lipomas are midline. 50% are dorsal and pericallosal. Other locations include the quadrigeminal, ambient, suprasellar and cerebello-pontine cisterns. A lipoma can be associated with agenesis or dysgenesis of the corpus callosum
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