Charcot-Marie-Tooth Disease: Extensive Cranial Nerve Involvement on CT and MR Imaging

Summary: We report a case of genetically verified Charcot-Marie-Tooth disease in which the patient had cranial nerve symptoms. CT and MR imaging demonstrated enlargement of several cranial nerves, as well as their skull-base foram-ina, with faint contrast material enhancement identified. Charcot-Marie-Tooth (CMT) disease is one of the hereditary motor and sensory neuropathy (HMSN) disorders, a group of genetically based disorders char-acterized by progressive motor weakness, decreased nerve conduction velocities, and nerve root enlarge-ment (1). Although these disorders are most often diagnosed clinically, MR and CT imaging in these patients is being used more frequently. The bulk of the imaging literature of this disorder concerns the identification of nerve root enlargement, often mas-sive, within the lumbosacral spine in patients with nerve compression syndromes (2–5). Involvement of cranial nerves, both clinically and radiographically, is thought to be quite rare. The following case illustrates involvement of several cranial nerves in a patient with CMT disease. Case Report At the time of initial presentation to our institution, the patient was a 64-year-old man with a history of lower extremity weakness that began in his second decade. Weakness had progressed over time and was associated with significant mus-cle wasting of both lower extremities and hands. The patient also had bilateral deafness and severe right facial pain diag-nosed as trigeminal neuralgia. The trigeminal neuralgia had been treated in the past with radio-frequency ablation and alcohol injection, but the patient had recurrent and severe symptoms (6). Of interest, review of the patient’s family history revealed two similarly affected relatives in an autosomal dominant pat-tern of inheritance (Fig 1). The diagnosis of CMT was verified with use of electrophysiologic testing, as well as genetic analysis (the latter was also performed on a total of 13 persons in the patient’s family). A novel deletion in the PMP22 gene was found in our patient (6). Both thin-section CT and MR imaging were performed. CT images demonstrated enlargement of multiple skull-base fo-ramina (Fig 2), whereas the MR images better demonstrated enlargement of the cranial nerves themselves (Fig 3)