Male, 15 years old, status post posterior fossa tumor resection. Evidence of recent occipital craniotomy is again seen for debulking of the cystic and solid posterior fossa tumor. Relative to the preoperative examinations, the dominant cystic portion of the lesion, which sits predominantly at the level of the CP angle cistern, has decreased in size likely representing resection or drainage. For example, the cystic portion now measures up to 33 mm in AP dimension, previously 38 mm. The more solid portion of the lesion, which is situated along the right aspect of the medulla and right foramen of Luschka projecting into the fourth ventricle has also been debulked to some degree. A small amount of T1 hyperintense blood product is evident within this portion of the lesion compatible with recent surgery.Ventriculomegaly appears similar to the prior exam. No evidence of any new supratentorial parenchymal signal abnormality or pathologic enhancement is seen.
Findings compatible with interval debulking of a large cystic and solid posterior fossa pilocytic astrocytoma.