Priapism in a patient with unstable hemoglobin: hemoglobin Köln.

We report a case of severe priapism occurring in a patient with unstable hemoglobin, hemoglobin Köln, and underline several factors that may have contributed to this complication: abnormal plasticity of red cells, splenectomy, and cytomegalovirus infection. Since emergency treatment may prevent impotence, patients and parents should be educated about this complication.