Focal sonographic periventricular pattern associated with mild ventriculomegaly in foetal cytomegalic infection revealing cytomegalic encephalitis in the third trimester of pregnancy

Objectives To report focal sonographic periventricular pattern related to residual germinal matrix lesions in foetal cytomegalic infection in association with mild ventriculomegaly seen during the third trimester of pregnancy correlating with neuropathological findings of encephalitis. Methods We reviewed prenatal cerebral sonographic examination performed in three patients, during the third trimester of pregnancy, looking for either late ‘isolated’ ventriculomegaly (n = 2) or sonographic follow‐up of cerebral structures following a known primary CMV infection in the early stage of pregnancy (n = 1). In cases of isolated ventriculomegaly, serological examination identified prenatal CMV infection. Magnetic resonance imaging (MRI) was performed in all cases. Imaging findings were compared with those following neuropathological examination. Results In all cases, ultrasound examination revealed an abnormal focal symmetrical bilateral periventricular pattern on the mid‐lateral border of the lateral ventricles, including a mainly hyperechogenic lesion containing a few microcysts (case 1), a mixture of echogenic tissue and cysts (case 2) and mainly cystic areas (case 3). No alteration of cephalic biometry was noted. Neuropathological examination correlated these abnormal areas with lesions of the residual germinal matrix including inflammation and necrosis, but revealed also an extensive inflammatory process of the whole foetal brain. Conclusions This focal sonographic periventricular pattern associated with mild ventriculomegaly without any abnormalities of the cerebral and cerebellar organogenesis nor cephalic biometry alteration in the third trimester of pregnancy should be considered as a marker of encephalitis following CMV infection of the foetal brain. Copyright © 2004 John Wiley & Sons, Ltd.