What condition is characterized by a painful erection that lasts for more than four hours?

Priapism is characterized by a painful, prolonged erection that lasts for more than four hours, which is not related to sexual stimulation or desire. This condition can arise from various causes, including blood disorders such as sickle cell disease, as well as the use of certain medications or recreational drugs. Understanding the implications of priapism is crucial, as it can lead to tissue damage and erectile dysfunction if not treated promptly.

The other conditions listed do not share this defining characteristic. Erectile dysfunction refers to the inability to achieve or maintain an erection, phimosis pertains to a condition where the foreskin cannot be fully retracted over the glans penis, and testicular torsion involves the twisting of the spermatic cord that cuts off the blood supply to the testicle, leading to severe pain. Therefore, priapism stands out as the condition specifically marked by an extended and painful erection.