Testicular abscess

Testicular abscess is usually a complication of severe epididymo-orchitis and needs to be distinguished from other testicular pathology that may present with similar clinical or imaging features. 

Epidemiology

The majority of patients develop a testicular abscess as a result of untreated or severe epididymo-orchitis. As such the demographics are the same, typically affecting young sexually active adult males ⁶. 

Clinical presentation

In most cases epididymo-orchitis has been present for some time, and thus typically patients present with testicular pain, often accompanied by fever and swelling, which have lasted a number of days. 

In a minority of cases a testicular abscess can result from bacterial infection an existing hematoma (as a result of testicular trauma) or of a region of infarction (secondary to testicular torsion or mumps) ³. 

If the abscess ruptures through the tunica albuginea then a scrotal abscess may develop. 

Pathology

Testicular abscesses are most commonly the result of epididymo-orchitis and thus share the same pathogens, and can be broadly divided into those that are sexually transmitted and those that are not ⁷:

• sexually transmitted

  • Neisseria gonorrhea

  • Chlamydia trachomatis

• not sexually transmitted

  • Enterococcus spp.

  • coliforms

  • Staphylococcus spp. (less common)

  • Streptococcus spp. (less common)

Radiographic features

Ultrasound

As with other testicular pathology, ultrasound is the modality of choice. Features consist of ^1,2,4,5:

• focal region of altered echogenicity

  • usually complex mixed solid/cystic structure

  • may be isoechoic to the rest of the testis

• focal region of altered vascularity

  • focal avascular region

  • surrounding increased vascularity

• evidence of epididymitis (in most cases)

• reactive hydrocoele

  • important to evaluate for debris or encapsulation to suggest a pyocoele

• scrotal skin thickening

  • important to assess for scrotal wall abscesses

• occasionally intrascrotal gas may be present

Nuclear medicine

Pertechnetate scintigraphy shows increased perfusion but decreased uptake centrally within the testis at the necrotic core of the abscess.

Treatment and prognosis

Management may include prolonged antibiotics, surgical debridement or even orchiectomy ^1,4. If a conservative approach is attempted (i.e medical therapy) then serial ultrasound examinations should be performed to ensure that the abscess does not progress. 

If successfully treated, the testis can return to near normal. In some instances, especially if swelling was pronounced, subsequent atrophy may develop. 

Differential diagnosis

Imaging differential considerations include:

• testicular cancer

• epididymo-orchitis

• epididymal abscess

• testicular torsion (with necrosis)

• testicular trauma