Background: Acute hemorrhagic occurrence of pilocytic astrocytomas is extremely rare but has become increasingly recognized and often presents in clinically emergent situations. The precise significance of hemorrhage in these tumors and its pathogenetic mechanisms have not yet been defined. Nothing is known about the natural history of bleeding pilocytic astrocytomas.
Case description: A 21-year-old man presented with acute biventricular hydrocephalus for repeat bleeding of a midbrain lesion that had been diagnosed 18 years earlier after a similar acute hemorrhagic episode. The patient had been initially treated conservatively, considering the high risk of surgery. He underwent urgent biventricular external shunt surgery and, subsequently, total removal of the lesion. Histopathological analysis revealed pilocytic astrocytoma. Including the present case, 59 cases were analyzed and reviewed, including 5 cases with a pilomyxoid variant. Different pathogenetic mechanisms have been proposed, including histological characteristics, rupture of the bridging veins torn by the neoplastic mass, and vascular instability determined by overexpression of vascular endothelial growth factor.
Conclusions: To the best of our knowledge, the presented case is completely unique owing to the long-term observational follow-up data available. The hemorrhagic potential did not decrease over time, representing a specific feature of this tumor. The occurrence of bleeding might not reflect either malignancy or aggressiveness. However, the worse prognosis is related to the clinical behavior, with life-threatening complications often associated. Surgery remains the standard treatment and will influence the final prognosis.
Keywords: Hemorrhage; Natural history; Pilocytic astrocytoma; Prognosis; Surgery.
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