A case of angiographically occult brainstem vascular malformation presenting solely with pathological laughing and crying is reported. Although this emotional syndrome has been seen in association with several different pathological entities, review of the literature failed to identify its occurrence as the only clinical expression of angiographically occult brainstem vascular malformation, or as a solitary symptom in any disease. Our data suggest that pathological laughing and crying can occur without any other manifestation of pseudobulbar palsy. An attempt is made to correlate this patient's clinical and radiological findings. This case was treated by stereotactic Bragg-peak proton beam therapy.