[A 63 year-old man with progressive gait disturbance and dysarthria]

We report a 63-year-old man with progressive gait disturbance and dysarthria. The patient was apparently well until the age of 62 (February, 1990) when he noted unsteadiness of gait. Two months later, dysarthria appeared. He was admitted to Juntendo Izunagaoka Hospital on April 23, 1990. Neurologic examination revealed a mentally sound man with normal higher cerebral functions. Cranial nerves were unremarkable except for scanning speech. His gait was ataxic with positive Romberg sign. No motor weakness was noted, however, he had hypotonia and cerebellar ataxia. Deep tendon reflexes were retained and the plantar response was flexor. Pain, touch and vibration senses were diminished in the distal parts of the lower extremities. Laboratory examination revealed a 2.5 cm mass in the left lung field. Cranial MRI revealed a small T1-low and T2-high signal intensity lesion in the left temporal lobe. Abdominal CT scan revealed multiple low density lesions in the liver. His subsequent course was complicated by progressive deterioration in his gait and loss of deep tendon reflexes. He expired on November 24, 1990. The patient was discussed in the neurological CPC and the chief discussant arrived at the conclusion that the patient had anti-Hu associated paraneoplastic encephalomyelitis and sensory neuropathy. Some other participants thought that the patient had carcinomatous cerebellar degeneration. Postmortem examination revealed a 4x4 cm mass lesion involving the left S4-S5 segments. Histologic examination of the tumor was small cell carcinoma. Many metastatic foci were found in the liver. The cerebral hemispheres were unremarkable except for a small wedge-shaped tissue defect in the left temporal lobe which appeared to have been caused by old head trauma which the patient had received. The cerebellar vermis showed slight enlargement of cortical sulci, however, the cerebellar hemispheres appeared unremarkable. Upon histologic examination, marked loss of Purkinje cells was noted, particularly in the cerebellar anterior lobe. The dentate nucleus showed slight cell loss with increase in fat granule cells. The inferior olive was normal. The histologic characteristics were consistent with the pathologic diagnosis of carcinomatous cerebellar degeneration. No evidence of limbic encephalitis was seen. The peripheral nerve was not examined.