Hemimegalencephaly with Facial Congenital Infiltrating Lipomatosis in a Child.

We report an unusual case of hemimegalencephaly (HMG) associated with ipsilateral congenital-infiltrating lipomatosis of the face in a five-month-old boy. Hemimegalencephaly is a rare but unique malformation characterized by enlargement of all or parts of a cerebral hemisphere. The affected hemisphere may have focal or diffuse neuronal migration defects, with areas of polymicrogyria, pachygyria and heterotopia. Our aim was to investigate morphologic abnormalities occurring on the affected hemisphere by Magnetic Resonance Imaging (MRI), but some MRI findings were also noted outside of the affected hemicerebrum. There are a few case reports that have described various other abnormalities accompanying this condition, such as enlargement of ipsilateral brainstem, cerebellum and left lateral ventricle. MRI may be the most useful method demonstrating features of hemimegalencephaly with infiltrating lipomatosis of the face. However, studies using electroencephalogram (EEG) and brain single photon emission computerized tomography (SPECT) can show distinct variants of discharges and brain-perfusion anomalies.