Abstract
We reported a case of Wallerian degeneration of the unilateral middle cerebellar peduncle (MCP) that developed after ipsilateral paramedian lower pontine infarction. The patient was a 70-year-old woman with right hemiparesis and dysarthria. Using a 3-Tesla scanner, cranial magnetic resonance imaging was performed, and an infarct was found at the left paramedian lower pons. Seven months later, an abnormal signal was found at the central portion of the left MCP, indicative of Wallerian degeneration of the pontocerebellar tract (PCT). There was no abnormality at the contralateral MCP. Usually, Wallerian degeneration of the bilateral MCPs may develop after unilateral paramedian pontine infarction, because bilateral PCTs cross each other at the midline of the basis pontis. In the present case, however, Wallerian degeneration was found at only the ipsilateral MCP. The contralateral PCT was not affected because the PCT runs in the craniocaudal direction, and our patient had a lower pontine infarct. The location of the pontine infarct (affected PCT) and the Wallerian degeneration of the side of the MCP were well correlated.