Testicular abscess is a focal suppurative infection of the testis, most commonly developing as the most serious complication of untreated or inadequately treated epididymo-orchitis. Ultrasound is the primary imaging modality and typically demonstrates a thick-walled complex hypoechoic/anechoic collection with internal debris and peripheral hypervascularity. Central avascularity (necrotic center) surrounded by peripheral ring vascularity is pathognomonic. DWI on MRI has high sensitivity in confirming abscess diagnosis with marked diffusion restriction. Testicular abscess may require orchiectomy; in small abscesses, surgical drainage and antibiotherapy may suffice. Delayed diagnosis increases risk of testicular loss, Fournier gangrene, and sepsis.
Age Range
20-60
Peak Age
35
Gender
Male predominant
Prevalence
Uncommon
Testicular abscess develops as a progression of acute bacterial epididymo-orchitis. The inflammatory process advances from interstitial edema and vascular congestion to microabscesses and eventually macroscopic abscess formation. Pathogenic organisms (E. coli, Pseudomonas, Klebsiella) reach the testis via retrograde route from the urinary system or hematogenously. Due to the non-distensible nature of the tunica albuginea, inflammatory edema leads to increased intratesticular pressure — disrupting microvascular perfusion and causing local ischemia and tissue necrosis. Bacterial proliferation and neutrophil accumulation in necrotic tissue forms a purulent collection (abscess). Inflammatory granulation tissue and a fibrous capsule (pyogenic membrane) develop around the abscess — this capsule appears as a thick hyperechogenic wall on ultrasound and a peripheral enhancing ring on MRI. In complicated abscesses, infection extends beyond the tunica albuginea causing peritesticular abscess, scrotal wall abscess, or Fournier gangrene. Bacterial toxins and inflammatory cytokines may trigger systemic inflammatory response (sepsis).
Central avascular area (necrotic abscess cavity) surrounded by peripheral ring hypervascularity on Doppler — reflecting neovascularization in granulation tissue of the abscess wall. This finding is pathognomonic for testicular abscess.
A well-defined or irregularly marginated, thick-walled (>3 mm) complex hypoechoic collection is seen within the testicular parenchyma. The collection contents may be homogeneously hypoechoic (simple pus) or heterogeneous (debris, fluid-debris levels, hyperechoic foci from gas bubbles). The abscess wall may have irregular or smooth contours. Surrounding testicular parenchyma shows orchitis findings (heterogeneous, enlarged). Fluid-debris levels may demonstrate movement of fluid with position change.
Report Sentence
A thick-walled complex hypoechoic collection with internal debris and fluid-debris levels is seen within the testicular parenchyma; findings are consistent with testicular abscess.
On color Doppler, the abscess content is completely avascular (necrotic purulent content) and peripheral ring hypervascularity is seen surrounding the abscess (ring sign). This finding is pathognomonic for testicular abscess and reflects neovascularization in inflammatory granulation tissue. Testicular parenchyma outside the abscess shows diffuse hypervascularity due to orchitis. Power Doppler is more sensitive than color Doppler and better demonstrates peripheral vascularity.
Report Sentence
The collection content is avascular on Doppler with surrounding peripheral ring hypervascularity (ring sign); this finding is consistent with testicular abscess.
The abscess content shows marked diffusion restriction on DWI — bright hyperintensity on high b-value images and markedly low signal on ADC maps. Diffusion restriction is the most sensitive MRI finding for abscess (>95% sensitivity). Inflammatory testicular parenchyma surrounding the abscess may also show mild diffusion restriction. ADC values are typically <0.9 x 10-3 mm2/s.
Report Sentence
The collection content shows marked diffusion restriction on DWI (ADC <0.9 x 10-3 mm2/s); this finding is consistent with abscess.
On T2-weighted images, the abscess cavity shows high signal (fluid/pus content) surrounded by a thick, irregular hypointense wall. The abscess content may show homogeneous or heterogeneous T2 signal — depending on protein and debris density. Surrounding testicular parenchyma is T2 hyperintense and enlarged due to orchitis. Peritesticular fluid (reactive hydrocele) shows bright T2 signal.
Report Sentence
A hyperintense collection surrounded by a thick hypointense wall is seen in the testicular parenchyma on T2-weighted sequences; findings are consistent with testicular abscess.
On post-contrast T1-weighted images, the abscess wall shows avid ring enhancement (rim enhancement). The abscess cavity does not enhance (avascular necrotic content). The enhancement ring may have uniform or irregular thickness. Surrounding orchitis-affected testicular parenchyma shows diffuse enhancement. This peripheral enhancement pattern is a critical MRI finding confirming abscess diagnosis.
Report Sentence
The collection wall shows avid ring enhancement on post-contrast T1 images while the central cavity does not enhance; findings are consistent with abscess.
On contrast-enhanced CT, a hypodense collection with rim enhancement is seen within or peritesticular to the testis. CT is particularly useful in evaluating complications (gas formation = emphysematous infection, Fournier gangrene, peritesticular extension). Scrotal wall thickening and peritesticular fat stranding accompany. Gas presence on CT worsens prognosis and requires emergent surgery.
Report Sentence
A hypodense collection with rim enhancement is seen in the scrotum on contrast-enhanced CT; scrotal wall thickening and peritesticular fat stranding are accompanying findings.
Criteria
Localized purulent collection within testicular parenchyma — usually solitary, well-defined. Develops in the setting of orchitis. Tunica albuginea intact.
Distinct Features
Thick-walled complex collection + ring sign on US. Marked restriction on DWI. Management with surgical drainage or antibiotherapy in small cases.
Criteria
Abscess developing outside the testis, in the epididymis or peritesticular tissue. Frequently located in the epididymal head as complication of epididymitis. Scrotal wall involvement possible.
Distinct Features
Testicular parenchyma may be relatively preserved. Epididymis enlarged and heterogeneous. Peritesticular fluid complex (pyocele). Surgical drainage usually sufficient.
Criteria
Necrotizing fasciitis — aggressive infection spreading from testicular/peritesticular abscess to perineum, scrotal wall, and perineal fascial planes. EMERGENT SURGERY. Mortality 20-40%.
Distinct Features
GAS in subcutaneous and fascial planes on CT (pathognomonic). Fascial thickening and fat stranding. Crepitus is clinical finding. Diabetes and immunosuppression are risk factors. EMERGENT wide debridement required.
Distinguishing Feature
Orchitis: diffuse heterogeneity and hypervascularity, NO focal avascular area. Abscess: focal avascular collection + peripheral ring vascularity. Orchitis can occur without abscess but abscess always develops in orchitis setting.
Distinguishing Feature
Seminoma: homogeneous hypoechoic solid mass, hypervascular, PAINLESS. Abscess: complex fluid collection, central avascular, PAINFUL + fever. Tumor markers (AFP, hCG) may be elevated in seminoma.
Distinguishing Feature
Torsion (late stage, necrosis): avascular, enlarged testis — may be confused with abscess. Torsion: whirlpool sign, spermatic cord rotation, ACUTE onset. Abscess: orchitis history, ring sign, focal collection.
Distinguishing Feature
Non-seminomatous GCT: heterogeneous solid-cystic mass, hemorrhage, calcification. Abscess: marked DWI restriction, clinical fever and infection signs. AFP/hCG elevated in GCT, CRP/WBC elevated in abscess.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
3-monthTesticular abscess requires urgent treatment. Small abscesses (<2 cm) may be managed conservatively with high-dose IV antibiotherapy but most cases require surgical drainage or partial/total orchiectomy. If extensive parenchymal damage exists, testis preservation may not be possible. In Fournier gangrene development, emergent wide debridement is life-saving. Post-treatment follow-up US should be performed at 4-6 weeks and complete resolution confirmed.
Testicular abscess is an emergency complication requiring urgent treatment. If IV antibiotic therapy fails (48-72 hours), ultrasound-guided percutaneous drainage or surgical drainage/orchiectomy is needed. Delayed treatment carries risk of Fournier gangrene. After orchiectomy, preservation of contralateral testis and hormonal evaluation are important. Prognosis is worse in diabetic and immunocompromised patients.