High-flow priapism leading to the diagnosis of lung cancer.

We report on a patient with spontaneous high-flow priapism. Magnetic resonance imaging showed a sacral tumor. Prior to tumor surgery, signs of lung cancer were found on chest X-ray. The diagnosis was confirmed by bronchoscopy. Priapism in this case can be explained either as a paraneoplastic symptom or as an isolated manifestation of cauda compression. Both are very uncommon reasons for priapism.