We report a case with Behçet’s disease with initial onset of affective symptoms. This disease most commonly affects the brain stem in the nervous system, but a large lesion is very rare in the pons; initial onset of affective symptoms has not yet been reported in literature. This case was treated successfully with corticosteroids. Total clinical improvement was observed and the lesion was reduced in size within nine months (1.5x1.3 cm to 0.2x0.4 cm).