[Neuroradiological findings of sporadic olivopontocerebellar atrophy with marked laterality and degenerative changes in the corticopontine tract].

We report a case of sporadic olivopontocerebellar atrophy (OPCA) with marked laterality of cerebellar atrophy and degenerative changes in the corticopontine tract. A 35-year-old man was admitted to our hospital for evaluation of titubation, gait disturbance, dysarthria, and urinary and fecal incontinence. Neurological examination showed a wide based gait, slurred speech, truncal ataxia, slightly saccadic ocular movement, and finger-to-nose incoordination, greater on the right than the left. Deep tendon reflexes were hyperactive and preserved with the right side greater than the left. Bilateral Babinski signs were present, and the patient had neurogenic bladder without orthostatic hypotension. Cranial MRI showed atrophy of the cerebellum with right dominance and of the pons. On T2- and PD-weighted images, high-intensity areas were detected at the left internal capsule, crus cerebri and ventral pons. These findings were compatible with the right dominance of the clinical symptoms. The high intensity area detected at the posterior internal capsule was more extensive than that seen in patients with motor neuron disease. This finding may coincide with the degenerative changes in the corticopontine tract. Moreover, 99mTc-HMPAO-SPECT showed the crossed cerebello-cerebral diaschisis (CCCD) pattern, which indicates the decreased CBF in the right cerebellar hemisphere and the left frontal lobe. These findings may reflect degenerative changes in the corticopontine tract in OPCA.