P05.55 Tumor location may be more predictive than histology for postoperative cerebellar mutism: case series

Abstract Background Assessment of complications from posterior fossa tumor surgery in children have been confounded by nonstandard definitions and nomenclature regarding speech, cognitive, and coordination deficits. Recently, a new definition of postoperative pediatric cerebellar mutism syndrome (PPCMS), emphasizing delayed onset reduced speech/mutism and emotional lability, has been proposed. Material and Methods A single-center, single-surgeon case series of posterior fossa brain tumor surgeries over a 6-year period was retrospectively reviewed. The relationships of PPCMS and discharge disposition to tumor location and diagnosis were examined. Tumor location was categorized as intrinsic to the 4th ventricle, cerebellar hemisphere, or brainstem; ventral brainstem and cerebellopontine angle tumors were excluded. Diagnosis was stratified as low grade or high grade histology. Discharge disposition was to home or an inpatient rehabilitation facility. Results 23 patients, age 11 months to 17 years at time of surgery, were studied. 9 patients had high grade histology (8 medulloblastoma, 1 anaplastic ependymoma) and 14 were low grade (7 pilocytic astrocytoma, 5 ganglioglioma, 2 low grade astrocytoma). By location, there were 12 4th ventricle, 7 cerebellar hemisphere, and 3 intrinsic brainstem tumors. 3 patients demonstrated PPCMS, all of which arose from 4th ventricle tumors (2 pilocytic astrocytomas, 1 medulloblastoma). By histology, 3 of 9 high grade and 8 of 14 low grade patients were discharged to inpatient rehab. By location, 7 of 12 4th ventricle and 2 of 7 cerebellar hemisphere patients were discharged to inpatient rehab. Conclusion Tumor location may be more predictive than histology of PPCMS and postoperative discharge disposition. Larger multiinstitutional studies using standardized definitions will better clarify PPCMS risk factors.