Degeneration of posterior column nucleus, inferior olivary nucleus and cerebellar cortex: system degeneration of paraneoplastic disease?

Degeneration of the posterior column nucleus, inferior olive, and cerebellar cortex is reported in a cancer patient. A 70-year-old man developed an ataxic gait and rapidly progressive disturbance of deep sensation over six months, followed by an abasic state. Early well-differentiated tubular adenocarcinoma was detected and total gastrectomy was performed. He died due to pulmonary tuberculosis about two years and nine months after the operation. Degeneration of the posterior column nuclei was found, explaining the disturbance of deep sensation noted in the clinical course, although there were few changes in the peripheral nerves, dorsal root ganglia, and spinal cord. Degeneration of the inferior olive and cerebellar corte was also found. Metastatic small cell carcinoma was present in the right pulmonary hilar and paratracheal lymph nodes at autopsy without any detectable primary focus. There was neither recurrence nor metastasis of the gastric carcinoma. This is the first case report of this type of central nervous system degeneration in a cancer patient, and its pathogenesis and etiology remain obscure. We discuss whether system degeneration or paraneoplastic degeneration was the etiology.