A patient with acromegaly may develop herniation of the cerebellar tonsils, possibly due to expansion of intracranial structures. A patient with acromegaly and certain clinical findings should have brain imaging to detect cerebellar herniation. Successful treatment of the acromegaly is usually associated with reversal of findings.

Clinical findings may include:

(1) headache

(2) vision problems

(3) other neurologic findings (sudden loss of leg strength, etc)


Some patients with cerebellar tonsillar herniation may be asymptomatic.


Imaging findings:

(1) Cerebellar tonsillar herniation was defined as distance > 3 mm (Barkovich, 1986).

(2) syringomyelia


The distance of cerebellar tonsillar herniation is based on a mid-sagittal MRI scan.

(1) A line is drawn from the lowest point of the basion to the lowest portion of the opisthion (foramen magnum).

(2) The distance that the cerebellar tonsils extend below this line is measured in millimeters.

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