CASE 11281 Published on 01.11.2013

Psoas abscess: uncommon complication of urethral stump


Uroradiology & genital male imaging

Case Type

Clinical Cases


La Pietra P., Sommario M., Marchini N., Chiaravalloti D.

Ospedale Bentivoglio,
Asl Bologna,
Dipartimento servizi;
Via Marconi
40121 Bentivoglio, Italy;

50 years, female

Area of Interest Abdomen, Urinary Tract / Bladder ; Imaging Technique Conventional radiography, CT
Clinical History
A 50-year-old woman, with a relevant clinical history of recurrent urinary tract infection for which she underwent a right nephrectomy for pyelonephritis as a baby, was admitted to our hospital because of onset of fever, urinary frequency and burning urination.
The laboratory tests revealed bacteriuria and increase of inflammatory parameters.
Imaging Findings
The abdominal ultrasound at admittance was unremarkable.
Due to worsening of clinical condition and onset of pain in the right flank, exacerbated with right hip motion, a contrast enhanced CT examination (CECT) was requested.
This showed a thickening of right psoas muscle which contains a low-attenuation collection with a peripheral rim enhancement.
During the delayed phase a vesicoureteral reflux was seen in the ureteral stump in the right side.
To confirm this finding and rule out a possible vescicoureteral reflux also to the left side a cystography was requested.
This confirmed the reflux of the right ureteral stump by showing a more important reflux also to the left side.
Psoas access (PA) is a collection of pus within the ileo-psoas muscle. First described by Minter in 1881 it is an uncommon disease, the incidence of which is estimated around 12 cases per year. The infection can arise from a haematogenous spread (primary abscess) or by direct extension of an infection from contiguous organs including: urinary tracts, pancreas, appendix, colon, small bowel and vertebral structures (secondary abscess) [1-2]. The urinary tracts are the less frequent origin, still less common is the origin from the ureteral stump. Usually, during a nephrectomy, it is not necessary to remove the lower end of the ureter because the ureteral stump remains free from pathological alterations and a complete ureterectomy lengthens operative time and can increase the morbidity and mortality [3].
Only in rare cases the residual ureter can be the site of a pathological process; this can occur also a long time after nephrectomy; frequently it is the same disease that made the surgery necessary to involve the ureteral stump.
Several cases of PA following nephrectomy have been reported in the literature [4-5-6-7].
The aetiology in these cases is vesicoureteral reflux in the ureteral stump and the spread by bladder infection.
PA is more common in middle-aged men and occurs with the same frequency on both sides, but bilateral abscesses are very uncommon. The typical symptoms: fever, flank pain, and limitation of hip motion are present only in a restricted number of cases, which makes the clinical diagnosis without the help of imaging techniques very difficult [2]. The abdominal radiograph frequently is normal, in some cases can show a mass effect, alteration of margins of the ileo-psoas muscle, destruction of vertebral bones or gas into soft tissues. Ultrasounds can detect an anechoic or hypoechoic lesion; however, the intestinal gas can obscure the retroperitoneal space making this imaging method less sensitive. CECT is the method of choice [8-9], the findings are: thickening of muscle which contains a low attenuation lesion that typically has a peripheral enhanced rim after contrast medium administration. Erosion of vertebral bones or gas into soft tissues can be secondary findings. MRI findings are similar. The treatment of PA consists of an adequate antibiotic therapy and a percutaneous drainage of the abscess. In our case the presence of bilateral VUR makes it necessary to prevent damages to the remaining kidney with a long-term antibiotic prophylaxis or surgical correction of VUR by transposition of the ureter or a subureteral endoscopic injection of dextranomer/hyaluronic acid [10-11].
Differential Diagnosis List
Psoas abscess
Iliopsoas haematoma
Iliopsoas tumour primary or metastatic
Final Diagnosis
Psoas abscess
Case information
DOI: 10.1594/EURORAD/CASE.11281
ISSN: 1563-4086