Which condition presents as a medical emergency when the foreskin cannot be retracted?

The condition that presents as a medical emergency when the foreskin cannot be retracted is paraphimosis. In paraphimosis, the retracted foreskin cannot be returned to its original position over the glans penis, leading to venous obstruction, edema, and can progress to arterial compromise. This situation demands urgent medical attention to avoid complications such as necrosis of the glans or severe pain.

Phimosis, on the other hand, refers to an inability to retract the foreskin from the glans but is generally not an emergency unless accompanied by acute symptoms or other complications. Hydrocele involves fluid collection in the scrotum and does not impact the foreskin or the glans, while testicular torsion is a different emergency associated with severe pain and a risk of loss of the testis but is not related to foreskin issues. Thus, paraphimosis is specifically the condition characterized by its emergency status due to the inability to return the foreskin to its position, requiring immediate intervention.