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

PurposeCharacterize hypertrophic olivary degeneration (HOD) that develops from posterior fossa masses and their treatments.MethodsRetrospectively reviewed MR images and clinical data of 10 patients with posterior fossa masses and HOD.ResultsEight 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).ConclusionsHOD may develop from posterior fossa masses and surgical and/or radiation therapy.