PMC8761798_01
Brain CT and MRI. (A) Axial plain CT reveals a round low-attenuation area with slightly high-attenuation rim in the left lenticular nucleus (arrow). (B) Axial gadolinium-enhanced T1-weighted MRI reveals ring enhancement in the area (arrow). (C, D) MRI following the initial treatment reveals enlargement of the existing abscess (arrow), and new ring enhancement (arrowheads) in the bilateral periventricular and subcortical areas. CT, Computed tomography; MRI, Magnetic resonance imaging.
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F1
Brain computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lesion in the left lenticular nucleus, suggestive of a brain abscess (Figures 1A,B). However, on day 24, we performed an additional brain abscess drainage on a CT-guided stereotactic procedure because follow-up brain MRI confirmed a gradual progression of the existing brain abscess and multiple new ones (Figures 1C,D). The timeline of the case presentation and clinical course is presented in Supplementary Figure 1.
Contrast-enhanced whole-body CT. (A, B) Pelvic CT reveals the irregularly-shaped enlarged prostate and the left seminal vesicle, which are replaced by encapsulated fluid cavities containing multiple gas bubbles (arrowheads), with spread of infection into extraperitoneal perivesicular space in the small pelvis. Note the left epididymal abscess (arrow). (C, D) Abdominal/pelvic CT shows marked dilatation of the left ureteral and renal pelvis (arrowheads), and multiple hypoenhancement foci in the left renal parenchyma (arrow). Note the thrombus in the left common iliac vein parallel to the dilated ureter (dotted arrow). (E) Abdominal CT reveals a centrally hypoattenuating lesion with peripheral heterogeneous enhancement in liver S7 (arrow). (F) Chest CT (lung window) reveals peripheral thick-walled cavitary nodule in the left upper lobe (arrow). CT, Computed tomography; UB, Urinary bladder.
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F2
Pelvic CT revealed an enlarged multilobular prostate gland characterized by capsulized fluid cavities and multiple gas bubbles, suggesting EPA caused by anaerobic bacteria (Figures 2A,B). We found direct extension as the 1st route, which involved spread into the left seminal vesicle and extraperitoneal space of the ischioanal fossa (Figures 2A,B), and an ascending infection of the ipsilateral urinary tract as the 2nd route, which caused left hydronephrosis, acute focal bacterial nephritis, and thrombophlebitis of the adjacent left iliac vein (Figures 2C,D). We also found a retrograde infection of the ipsilateral spermatic duct as the 3rd route, which led to an epididymal abscess (Figure 2A), and hematogenous spread to the liver (Figure 2E) and lungs (Figure 2F) as the 4th route.
Pelvic magnetic resonance imaging. (A) Axial DWI shows characteristic restricted diffusion on the left lobe of the prostate extending to the opposite lobe and bilateral perivesicular extraperitoneal spaces (arrowheads). (B, C) Axial and sagittal T2WI shows obviously multilocular abscess of both prostate and left seminal vesicle (arrowheads), with a fistulous communication of the bulbar urethra (arrow). DWI, diffusion-weighted image; T2WI, T2-weighted image; UB, urinary bladder.
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F3
Pelvic MRI further characterized the pelvic infection and revealed active prostatic inflammation involving the urinary bladder and left seminal vesicles, which ruptured into the extraperitoneal perivesicular space, and subsequent fistula formation of the bulbar urethra with the prostate (Figure 3).