Rate of spontaneous hemorrhage in histologically proven cases of pilocytic astrocytoma

Object. Spontaneous intracerebral hemorrhage is an uncommon but recognized initial presenting sign of both primary and metastatic brain tumors. The rate of tumor-related intracranial hemorrhage is variably reported from < 1 to 14.6%. Hemorrhage in primary gliomas occurs in 3.7-7.2% of gliomas, mainly in glioblastoma muliforme and oligodendroglioma with low-grade astrocytomas accounting for < 1%. Hemorrhage associated with pilocytic astrocytomas (PAs) is only sporadically reported. The authors report on a series of patients in whom PAs presenting as hemorrhages prompted them to examine the incidence of bleeding in these tumors. Methods. Cases involving a confirmed tissue diagnosis of PA from 1994-2005 were reviewed retrospectively. The authors included only patients with evidence of hemorrhage on computed tomography and/or magnetic resonance imaging seen prior to biopsy or resection and in the absence of trauma or other vascular pathological entities. Results. In 138 patients with histologically proven PAs, the mean age at diagnosis was 23 years. In 11 patients (8%; 5 male and 6 female) there was evidence of hemorrhage at presentation. There were no locations more susceptible to hemorrhage than any other, although no bleeding occurred within the cerebellum. All but 1 patient was treated with a gross-total resection. Conclusions. Hemorrhage in association with PAs likely results from the frequently observed abnormal vasculature in these tumors, occurs with a greater frequency than previously thought, and should be considered in the differential diagnosis of spontaneous intracerebral hemorrhage.