[A case of unilateral brain-stem tumor and impaired ventilatory response].

A 44-year-old man with a unilateral brain-stem tumor (ganglioglioma) presented with marked hypoventilation and irregular breathing. His respiratory muscle strength was impaired slightly, and his ventilatory responses to chemical stimuli were markedly diminished. Magnetic resonance imaging of the brainstem revealed that the tumor was located in the left superior cerebellar peduncle and the medulla, and involved the left lateral portion of the medullary reticular formation, ambiguous nucleus, and solitary nuclear complex. From these findings, we conclude that the abnormality of ventilatory control may have been caused by damage to both the unilateral respiratory neuron group in the medulla and the afferent pathway to the respiratory motor unit on the opposite side.