Cerebellar mutism in adults after posterior fossa surgery: a report of 2 cases

Abstract

Background

Mutism has been associated with injury to midline cerebellar structures secondary to degenerative disease, tumors, hemorrhage, or surgery. Typically, cerebellar mutism syndrome (CMS) has been seen in children and only rarely described in adults after surgery of the posterior fossa. This syndrome typically arises 48 hours after the initiating event and resolves approximately 7 to 8 weeks later. Characteristics of CMS include complete absence of speech without impaired consciousness, other cranial nerve deficits, or long tract signs.

Case Description

The authors report on 2 patients each of whom developed cerebellar mutism after tumor resection using a posterior fossa approach. The first patient underwent gross total resection of a pineal region tumor via a supracerebellar approach. The second patient underwent posterior fossa decompression for a left cerebellar hemispheric renal cell carcinoma metastasis with adjacent hemorrhage. One patient displayed a variant of cerebellar mutism with severe ataxic dysarthria without complete absence of speech, whereas the other demonstrated frank mutism. After neuroimaging studies confirmed the absence of a surgically treatable postoperative cause for the patients' symptoms, they were managed in a supportive fashion (eg, speech therapy) and improved within 3.5 months and 1 year, respectively.

Conclusion

It is paramount that neurosurgeons be aware of cerebellar mutism with regard to its very rare occurrence in adults, its time of onset, and typical self-limiting course.

Introduction

Cerebellar mutism is often considered to be the most extreme form of ataxic dysarthria and is defined as a disturbance of speech and language caused by a lesion to the cerebellum [1], [7], [10]. The spectrum of disturbances can vary from complete absence of speech to hesitant outburst of speech or even monotonous explosive speech [1]. Cerebellar injury secondary to degenerative disease, tumors, hemorrhage, or surgery has been associated with mutism [2]. This condition has rarely been reported in adults as result of injury to cerebellar structures secondary to tumor resection in the posterior cranial fossa.