Recurrent medulloblastoma. There are postoperative findings related to prior right suboccipital craniotomy. There is a heterogeneous mass in the right cerebellar hemisphere treatment bed, which measures up to nearly 4 cm. There is no evidence of other intracranial lesions. The ventricles are unchanged in size and configuration, including partial effacement of the fourth ventricle, but no evidence of hydrocephalus. The cerebellar tonsils are mildly low-lying, but there is no midline shift. There are skin fiducial markers.
Preoperative planning MRI demonstrates a mass in the right cerebellar hemisphere treatment bed, which likely represents recurrent neuroblastoma.