Tumefactive dilated perivascular space with spontaneous regression.

Tumefactive (giant) perivascular spaces of the brain are a rare benign lesion that may occasionally result in localized neurological symptoms and typically do not change in appearance on subsequent imaging studies. Here we report a case of a 65-year-old woman with newly diagnosed lung cancer that underwent routine staging MRI of the brain. She was found to have a cystic temporal lobe lesion with imaging features consistent with a tumefactive perivascular space.