Hemimegalencephaly in the Klippel-Trenaunay-Weber syndrome

The Klippel-Trenaunay-Weber syndrome is characterized by skeletal and soft-tissue hypertrophy, segmentally distributed cutaneous nevi, and vascular anomalies. Only a few cases of this syndrome associated with hemimegalencephaly have been reported previously. However, we have experienced such a case of Klippel-Trenaunay-Weber syndrome with hemicranial hypertrophy, and so have analyzed this case from the neuroradiological point of view. The patient was a 6-month-old female with hemihypertrophy and hemimegalencephaly on the same, right side. A skull X-ray showed that the skull and facial bones were all hypertrophic on the right side and that all the sutures were open. A CT scan demonstrated that all the intracranial structures, including the ventricle on the right, were larger than those on the left. On the right side, we noticed a periventricular low-density area and spotted a calcified high-density region adjacent to the anterior horn of the lateral ventricle. Metrizamide CT cisternography exhibited ventricular stasis at 6 hours and a delayed clear-up in the subarachnoid space over the cerebral convexity in 24 hours. When we used the inversion recovery method on magnetic resonance imaging, the white matter on the right, especially in the periventricular area, was shown by a lower signal intensity than was that on the left. This could be thought to indicate the poor progress of the myelination process on the right side of the cerebrum. (author)