Author Affiliations: Department of Radiology, Mayo Clinic, Rochester, Minnesota.
A 46-year-old man presented with a history of dizziness, headache, and incoordination. His symptoms started suddenly 1 month before presentation and gradually progressed. Magnetic resonance imaging (Figure, A and B) demonstrated a prepontine mass with numerous T1 hyperintense droplets indicating a ruptured posterior fossa epidermoid with dissemination of its contents around the cerebellar hemispheres and along the leptomeninges of the parietooccipital sulcus (Figure, A, arrows). Fat-fluid level in the lateral ventricle was also seen (Figure, A, asterisk). Remarkable hydrocephalous was noted and the patient underwent ventriculoperitoneal shunting. Because of persistent symptoms after shunting, a computed tomographic scan (Figure, C) was done 1.5 months after initial presentation that revealed fat density in the prepontine and ambient regions of T1 hyperintensity, confirming the lipid content (Figure, C, arrow) and improvement of the ventriculomegaly. His symptoms progressively improved without additional treatment and were “tolerable” 17 months after original presentation.
Loumiotis I, Morris JM. Central Nervous System Epidermoid Cyst Rupture. Arch Neurol. 2012;69(1):136–137. doi:10.1001/archneurol.2011.550