Nodulus and Flocculus damage from a cerebellar astrocytoma

Timothy C. Hain, MD • Page last modified: March 27, 2021

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A young man was self referred for dizziness, 3 years following resection of a cerebellar astrocytoma. The main complaint was dizziness, and sensitivity to multiple sensory inputs.

Cerebellar astrocytoma

The images above show a cystic cerebellar astrocytoma, with a tumor nodule in the anterior portion of the cerebellum, and a large cyst in the left cerebellum, compressing the nodulus and flocculus on the left.

Post-surgical MRI

The images above show similar sections after surgery. The anterior lower portion of the left cerebellum is resected. The flocculus appears to be absent, but the nodulus is probably still present.

Poor fixation suppression


Computerized balance testing (CDP) was completely normal shortly after surgery.

On examination, about 3 years after surgery, he had normal coordination and balance, but visual fixation was very poor, there was positional nystagmus, and vertical head movement as well as vertical OKN provoked torsional eye movement.