Intracranial organizing hematoma with papillary endothelial hyperplasia features after resection and involved field radiotherapy for cerebellar juvenile pilocytic astrocytoma.

This article describes a case of organizing hematoma with features of papillary endothelial hyperplasia arising at the site of a right cerebellar juvenile pilocytic astrocytoma previously treated with surgery and involved-field radiation therapy. CTA demonstrated a mass with abnormal vascularity in the treatment bed. MRI demonstrated the evolution of the lesion from a cystic mass with a heterogeneously enhancing nodule with blood products into a nearly solid-enhancing mass with abundant areas of susceptibility effect and surrounding vasogenic edema. These imaging features warrant considering papillary endothelial hyperplasia in the differential diagnosis for a mass that develops after radiotherapy.