Traumatic injury: This is the most likely diagnosis for a penile laceration, as it is a direct result of physical trauma to the penis, which could be due to accidental injury, sexual activity, or assault. The presentation typically includes a visible cut or tear on the penile skin.

Circumcision complication: Complications from circumcision, especially if performed in non-sterile conditions or by inexperienced individuals, can lead to lacerations or tears of the penile skin.
Sexually transmitted infections (STIs): Certain STIs, like syphilis, can cause ulcers or lesions that might be mistaken for lacerations. However, these are typically not as acute or traumatic in appearance.
Penile fracture: Although not a laceration per se, a penile fracture (a rupture of the tunica albuginea) can present with swelling, pain, and sometimes a visible deformity, which might be confused with a laceration in the initial assessment.

Penile cancer: Although rare, any unexplained or non-healing lesion on the penis should prompt an investigation for penile cancer. Early detection is crucial for effective treatment.
Surgical complications: Complications from previous surgeries, such as those for phimosis, paraphimosis, or penile implants, could potentially lead to lacerations or the appearance of lacerations due to infection or device malfunction.

Behçet's disease: A rare condition characterized by recurrent ulcers, including genital ulcers that could resemble lacerations, along with other systemic symptoms.
Fournier's gangrene: A severe and potentially life-threatening condition involving necrotizing fasciitis of the genital area, which could initially present with what appears to be a laceration but rapidly progresses to more severe symptoms.
Factitious disorder: In some cases, individuals may self-inflict injuries, including lacerations, for various psychological reasons, making it a rare but important consideration in the differential diagnosis.