Binucleated neurons in the pontine nuclei in neuro-Behcet's disease: a study of 3 autopsy cases

Neuropathological findings of three autopsy cases of neuro-Behçet's disease are presented with special reference to the frequent occurrence of binucleated neurons in the pontine nuclei. All 3 patients were men and died after a protracted clinical course characterized by various brain stem symptoms. Autopsies revealed chronic non-specific brain stem encephalitis, which is a typical neuropathological feature of neuro-Behçet's disease. In all cases, many binucleated neurons (19, 20, and 55 neurons in each case) were found in the pontine nuclei. For comparison, the occurrence of binucleated neurons in the pontine nuclei was examined in 67 control cases including various neurological disorders. In 55 cases (82.1%) among them, no binucleated neurons were detected. In the remaining 12 cases (17.9%), the pontine nuclei contained 1 or 2 binucleated neurons. These observations confirmed that the occurrence of many binucleated neurons in the pontine nuclei was a characteristic finding in neuro- Behçet's disease. Although the pathogenetic mechanism for the formation of binucleated neurons is unknown, it is most likely the result of abortive cell division of neurons or fusion of the perikarya of the adjacent neurons. It probably reflects the presence of intense local noxious stimuli affecting neurons in the pontine nuclei.