Postoperative cerebellar mutism syndrome following treatment of medulloblastoma: neuroradiographic features and origin

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The origin and long-term outcome of cerebellar mutism syndrome (CMS), a postoperative syndrome of diminished speech, hypotonia, and ataxia that affects approximately 25% of patients with medulloblastoma, is poorly elucidated. The current study was undertaken to determine factors associated with development of CMS, a means to determine its severity or cause, and outcomes of patients with this syndrome.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The study included 28 children with medulloblastoma who either underwent an operation or were referred to the authors' institution soon after surgery. Eleven (39%) of these children had CMS. The preoperative, immediate postoperative, and 1-year postoperative MR images were reviewed by a neuroradiologist blinded to diagnosis of CMS. The severity of mutism and neurological and neurocognitive outcomes were examined.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Preoperative MR images showed no differences in tumor size, hydrocephalus, or peritumoral edema in patients with and without CMS. An association with brainstem invasion was significant (p &lt; 0.05), and there was a trend toward an association with involvement of the cerebellomedullary angle (p = 0.08). Images obtained immediately postoperatively showed cerebellar edema in 92% of all patients; there were trends for more middle and superior cerebellar peduncle edema in patients with CMS (p = 0.05 and 0.07, respectively). At 1 year postoperatively, patients with CMS showed more moderate to severe atrophy/gliosis of total cerebellum (p &lt; 0.01), vermis (p &lt; 0.01), and brainstem (p &lt; 0.05). Mean IQ was 16 points lower in patients with CMS (IQ = 84.2 ± 15.8) compared with those without CMS (IQ = 100.4 ± 17.4), with a trend toward significance (p = 0.07).</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>This study demonstrates that CMS is associated with postoperative damage to the cerebellum and brainstem, damage not predicted by immediate postoperative MR imaging, and with poorer associated functional outcome.</jats:p></jats:sec>

Clinical significance and limitations of repeat resection for pediatric malignant neuroepithelial tumors

“…In fact, 7 (26.9%) of 26 patients who had a medulloblastoma had cerebellar mutism after the initial surgery. The incidence of cerebellar mutism after medulloblastoma surgery is reported to range from 11% to 39%, 7,30 which is compatible with our findings. Moreover, none of our patients developed meningitis or required surgical treatment for wound infection.…”

Cerebellar mutism

“…Brainstem involvement seems to be the most important, including preoperative tumor invasion or postoperative edema. 26,52,108 Moreover, McMillan et al 61 supported that brainstem compression could be used as a predictor of postoperative CM. Some authors believe that midline location predisposes to the occurrence of CM, 9,36,53,55 while others have found no significant difference.…”

“…The incidence of CMS has been reported to range from 8% 46 to 39%, 9,15,40,52,55,62,82,108 although there are reviews reporting a lower rate of 1.6%. 17 In the largest prospective study so far of 450 children who underwent surgery for medulloblastomas, the incidence of CMS was found to be 24%.…”

“…A high incidence of brainstem compression preoperatively in addition to edema in brainstem and superior cerebellar peduncle among patients with CMS postoperatively seems to confirm their role in CMS. 108 Di Rocco et al 17 suggested that dominant-site DTC tract involvement was adequate enough for CMS to appear. Transient dysfunction of the neurons of the A9 to A10 dopaminergic cell group in the mesencephalon, which play a major role in the mesencephalofrontal activating system, has also been proposed as a possible anatomical substrate of CM.…”

“…It usually appears as a consequence of posterior fossa surgery in children with cerebellar or fourth ventricle tumors. 52,82,108 Other causes that have been reported are infections, 15,19,24,26,72 posterior fossa hematomas (surgically removed 31,89 or not 60 ), arteriovenous malformations, 33,51,82 a brainstem tumor, 82 a pineal gland tumor, 23 and traumatic cerebellar injury. 15,82 Although this clinical entity is mainly seen in children, there are also reports of CM in adults.…”