Case of the month: May 1999 - 16 year old male with an unexpected MRI finding - Pilocytic astrocytoma (WHO grade I) with widespread dissemination in the CNS.

Four years after resection of a supratentorial pilocytic astrocytoma this 1 6-year-old boy displayed widespread leptomeningeal seeding. Although the pr imary tumor lacked contrast enhancement, the multiple metastatic nodules we re markedly contrast enhancing. Both the initial and disseminated tumor wer e consistent with a pilocytic astrocytoma. He was treated with vincristin a nd carboplatinum and the tumor was stable up to Dec. 1998. Dissemination of low-grade intracranial astrocytoma in children occurs in only 4%. It is no t a sign of malignancy. The present case is similar to previously published cases. The prognosis of these patients might be quite favorable when treat ed with radiotherapy and/or chemotherapy.