Juvenile pilocytic astrocytoma presenting with subarachnoid hemorrhage. Case report and review of the literature.

The authors report a case of a 13-year-old boy with juvenile pilocytic astrocytoma (JPA) presenting with subarachnoid hemorrhage (SAH). The patient experienced sudden onset of headache, vomiting, and loss of consciousness. Cranial computerized tomography scanning revealed blood within basal cisterns and the third ventricle. Angiography demonstrated normal cerebral vasculature and upward displacement of the bilateral A, segments of the anterior cerebral artery. Magnetic resonance (MR) imaging revealed a chiasmatic/hypothalamic mass with evidence of hemorrhage. The mass was surgically decompressed. Histopathological examination showed evidence of JPA. In all cases of SAH in which there is blood around the third ventricle and a raised A1 segment on angiography, MR imaging should be performed. The presence of a normal sella turcica, as well as indistinct margins between the tumor and the opticochiasmatic apparatus should raise suspicion about the lesion.