2023 年 2 巻 3 号 p. 217-221
The perivascular space is a normal anatomical structure that forms around perforating arteries and is filled with cerebrospinal fluid. In rare cases, the perivascular space is enlarged and form multiocular cysts measuring 1.5 cm or larger, which are called giant tumefactive perivascular spaces. Seventy-four cases who harbored tumefactive perivascular spaces have been reported to date, and about half of them required CSF diversion. The treatment for multiocular cysts themselves has been reported as being unnecessary. Herein, we report a case of a giant tumefactive perivascular space that caused obstructive hydrocephalus. In the case of obstructive hydrocephalus due to giant tumefactive perivascular spaces, the surgical intervention for the hydrocephalus, such as third ventriculostomy or ventricle-peritoneal shunt, would be the therapeutic choice. Thus, it is crucial to understand the characteristic imaging findings of giant tumefactive perivascular spaces; the signal of the lesions is isointense to the cerebrospinal fluid on each MRI sequence with minimum perifocal edema.