Spontaneous Resolution Chiari I Malformation in an Adult.

BACKGROUND AND IMPORTANCE: With the wide availability of MRI for brain and cervical spine complaints, adult patients are diagnosed with Chiari I malformation (CMI) frequently. Although there are few reports of spontaneous resolution of CMI in adults, it is important to consider when choosing conservative vs surgical management in minimally symptomatic and asymptomatic patients. CLINICAL PRESENTATION: A woman presented at age 55 with a 2-year history of left-sided headaches and left facial numbness. MRI brain demonstrated cerebellar tonsillar ectopia 12 mm below the foramen magnum. Owing to atypical symptoms, surgical management was not recommended. She presented 10 years later with dizziness and gait disturbance. MRI cervical spine showed resolution of cerebellar tonsillar ectopia and no syringomyelia. CONCLUSION: We identified 7 cases of spontaneous regression of adult CMI in the literature. Unlike the previous cases, this patient never had definitive symptoms attributable to CMI. This case illustrates radiographic resolution of cerebellar tonsillar ectopia and strengthens the argument for conservative management in patients with radiographic cerebellar tonsillar ectopia and atypical symptoms.