Subtotal resection of enhancing lesion. There are interval postoperative findings related suboccipital craniotomy for biopsy with an extradural fluid collection that measures up to approximately 15 mm in thickness. There is a persistent focus of nodular enhancement along the posterior aspect of the inferior medulla that measures up to 8 mm. There is a left transfrontal catheter that terminates in the atrium of the left lateral ventricle and a right transparietal catheter that terminates in the right anterior parafalcine region. The ventricles are unchanged in size and configuration. There is unchanged encephalomalacia in the right posterior frontal and parietal lobes. There is no evidence of acute infarction. There is colpocephaly with dysgenesis and thinning of the corpus callosum. There is unchanged beaking of the tectum and prominence of the mass intermedia. The fourth ventricle remains partially effaced, with paucity of choroid plexus tissue. The CSF flow study demonstrates biphasic flow anteriorly at the level of the foramen magnum, but relative paucity of flow posteriorly.
1. Interval postoperative findings related to inferior cerebellar biopsy with a persistent subcentimeter lesion along the posterior aspect of the medulla, which likely represents ectopic choroid plexus.2. Unchanged intracranial stigmata of Chiari II malformation and the shunted ventricular system. 