A case of central neurogenic hyperventilation without tachypnoea.

Central neurogenic hyperventilation (CNH) is a rare condition, with 37 cases reported in the literature to date. The underlying mechanisms remain unclear. Primary central nervous system lymphoma (PCNSL) is the most common cause of CNH, with 17 cases reported so far. Among these, CNH was usually accompanied by tachypnoea. Only two cases, including the present case, showed CNH with normal respiratory rate. Here, we present a case of PCNSL-induced CNH in a 60-year-old man. Magnetic resonance imaging of the brain demonstrated hyperintensity of the left cerebral cortex, basal ganglia, corona radiata, midbrain, and ventral pons on fluid-attenuated inversion recovery. The patient complained of dyspnoea and showed hyperventilation without tachypnoea on admission or during hospitalization. Examining CNH cases without tachypnoea and comparing those cases to cases of CNH with tachypnoea might provide new insights into the mechanisms of CNH. Moreover, it should be remembered that CNH can occur without tachypnoea.