Hypertrophic olivary degeneration resulting from posterior fossa masses and their treatments.

ABSTRACT

PURPOSE: Characterize hypertrophic olivary degeneration (HOD) that develops from posterior fossa masses and their treatments. METHODS: Retrospectively reviewed MR images and clinical data of 10 patients with posterior fossa masses and HOD. RESULTS: Eight patients had cerebellar lesions, and two patients had pontine lesions. Lesions consisted of tumors, demyelination, and nonspecific necrosis. MRI showed T2 hyperintense signal in the inferior olive a median 86 days after the diagnosis of a posterior fossa lesion. HOD presented prior to surgery (n=2), after surgery (n=3), after surgery/radiation therapy (n=4), or without treatment (n=1). CONCLUSIONS: HOD may develop from posterior fossa masses and surgical and/or radiation therapy.