IS Case 206: Testicular rupture
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
Testicular trauma is defined as any injury sustained by the testicle. Types of injuries include blunt, penetrating, or degloving. Blunt trauma refers to injuries sustained from objects applied with any significant force to the scrotum and testicles. Degloving injuries or avulsion injuries are less common. With these, scrotal skin is sheared off, for example, when a testicle becomes trapped in heavy machinery.
Testicular rupture or fractured testis refers to a rip or tear in the tunica albuginea resulting in extrusion of the testicular contents. Testicular dislocation is an uncommon and sometimes easily overlooked event that refers to a testis that has been relocated from its orthotopic position to another location secondary to blunt trauma. Indirect inguinal hernias and atrophic testicles may be predisposing factors. Most cases are the result of motorcycle crashes, and one-third involve both testicles. Possible routes include superficial inguinal, pubic, preputial, acetabular, canalicular, penile, intra-abdominal, retrovesical, perineal, and crural dislocations. Diagnosis should be followed by early treatment in the form of manual closed reduction and surgical fixation if closed reduction is unsuccessful.
The testis is enveloped by layers of white fibrous connective tissue called the tunica vaginalis and the tunica albuginea. The tunica albuginea is the visceral layer that covers the testis, and the tunica vaginalis is the parietal layer that lines the hydrocele sac.
The tunica albuginea is the layer that is violated during a testicular rupture. Approximately 50 kg of force is required to rupture the testicle. A tear in the tunica albuginea leads to extrusion of the seminiferous tubules and allows an intratesticular hemorrhage to escape into the tunica vaginalis. This is referred to as a hematocele. Disruption of the tunica vaginalis or extension to the epididymis leads to bleeding into the scrotal wall, resulting in a scrotal hematoma.
Scrotal ultrasound imaging with Doppler studies is valuable for diagnosing and staging testicular injuries. A normal parenchymal echo pattern, with normal blood flow in cases of blunt trauma, can safely exclude significant injury. Acute bleeding or contusion of the testicular parenchyma typically appears as a hyperechoic area, whereas old blood appears as a hypoechoic lesion. Acute and chronic hematoceles are observed as mixed hypoechoic and hyperechoic areas confined by the tunica vaginalis. The most specific finding for testicular rupture is a discrete fracture plane, but this is only seen 17% of the time.
- Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. 2nd ed., Lippincott Williams & Wilkins, 1999: 873
- Weissleder R, Wittenberg J, Harisinghani MG, Chen JW. Primer of Diagnostic Imaging. 4th ed., Philadelphia, Mosby, 2007:328