Closed Meningo(encephalo)cele: a new feature in Hunter syndrome.

Hunter syndrome (MPS type III) is a rare X-linked recessive disease caused by lysosomal enzyme iduronate-2-sulfatase deficiency, characterized by frequent and variable brain and skull involvement. Our objective was determine the frequency of closed cephaloceles in a large cohort of subjects affected with Hunter syndrome and to investigate possible correlations with clinical and neuroradiologic findings. Brain MR imaging of 33 patients (32 males and 1 female, age range 2.5-30.8 years, mean age 10.4 years) affected with Hunter syndrome were retrospectively evaluated. Eleven (age range 3.6-30.8 years; mean age 15.1) presented with an "attenuated" phenotype, while 22 (age range 2.5-19.1 years; mean age 8.2) had a "severe phenotype. A closed cephalocele was detected in 9/33 patients (27%) at the level of anterior and middle fossa in 6 and 3 cases, respectively; 6/9 subjects were affected with the attenuated phenotype and 1/9 suffer from epilepsy. Closed cephaloceles did not show a significant association with other brain and spine MR imaging features of Hunter disease, such as enlargement of perivascular spaces, cisterna magna, pituitary sella, ventricles and subarachnoid spaces, craniosynostosis, dens hypoplasia, white matter abnormalities, spinal stenosis due to periodontoid cap, platyspondylia, or intervertebral disk anomalies. Closed cephaloceles are frequent in Hunter syndrome and should be considered a neuroradiologic feature of this disease.