Teaching Case

An 11-year-old, mentally retarded boy presented with a long history of seizures and gradually progressive , bilateral motor weakness. The patient had total loss of vision on the right. He had a port-wine nevus on the right side of his face.

An 11-year-old, mentally retarded boy presented with a long history of seizures and gradually progressive , bilateral motor weakness. The patient had total loss of vision on the right. He had a port-wine nevus on the right side of his face. An MRI study of the cranium was performed in three planes with a 1.5 T MR scanner , with pre- and post- contrast SE T1, FSE PD-T2 and GRE T2* sequences. The examination revealed a left temporal lobe cystic mass, containing a hemorrhagic fluid-fluid level. The tumor also contained a solid component anteriorly. After IV Gd-DTPA injection, the solid tumor nodule and the rim around the cyst enhanced strongly. Taking into account the size of the mass, there was little vasogenic edema. There was mass effect with compression of the mesencephalon, midline shift, and displacement of the third and left lateral ventricles. Compression at the level of the foramen of Monro, caused dilatation of right lateral ventricle and transependymal CSF resorption. Dystrophic cortical and subcortical calcifications are seen with as hypointense lesions on the GRE T2* sequence. Post contrast T1 WI demonstrated extensive enhancement of leptomeningeal surface over the right cerebral hemisphere and deep in multiple sulci. In the right bulbus oculi there was a “V” shaped lesion, hyperintense on T1 WI and hypointense on T2 WI consistent with retinal detachment. After surgical resection of the left temporal lobe mass, the histopathologic diagnosis was pleomorphic xanthoastrocytoma.

Sturge-Weber syndrome is a rare neurocutaneous disorder characterized by cutaneous facial angioma, leptomeningeal angioma associated with seizures and other neurologic complications including mental retardation, and glaucoma. Seizures often begin in the first year of life. They are the initial presenting feature in 80 % of patients and are often intractable. Hemiparesis is also present. Glaucoma occurs on the affected side in up to 40% of the patients. In the gross pathology of the disease, a lack of superficial cortical veins leeds to impaired venous drainage, resulting in hemostasis and eventually ischemic injury to the brain. The meningeal angioma usually confined to the pia matter. Cortical calcifications occur subjacent to the meningeal angioma and usually are not seen in the first years of life. Tram track calcifications may be seen on skull films.CT examination of the cranium reveals cortico-subcortical calcifications and hemispheric atrophy. On MRI of the cranium,parenchymal atrophy, marked gadolinium enhancement in areas of leptomeningeal angiomatosis is seen. T2 shortening in the white matter underlying the angiomatous malformation, usually seen in infants is possibly due to ischemia. In our case, a left temporal lobe pleomorphic xanthoastrocytoma (PXA), which was not reported in the literature before was seen coincidentally. PXA is a rare, usually benign neoplasm that represents a histologically different astrocytoma subtype. It’s thought to originate from subpial astrocytes of the superficial cortex. The most common location is in the temporal lobes. These tumours mostly occur in children and young adults. Seizures and headaches are common clinical features.These tumors are well-demarcated, cortically-based, partially cystic masses with a discrete mural nodule. The nodule usually enhances after contrast material injection. Leptomeningeal adhesion is common. Although generally regarded as a benign lesion in the literature, PXA has potential for aggressive behavior.As PXA can become malignant even after many years of benign behaviour, a long term follow up is necessary.