Diagnostic Ultrasound - Abdomen and Pelvis

Perinephric Hematoma
Diagnoses: Urinary Tract
TERMINOLOGY
• Hemorrhagic collection in perinephric spaces: Subcapsular,
perirenal, anterior and posterior pararenal
IMAGING
• Avascular solid or cystic masses in 1 or more perinephric
spaces
• Echogenicity of blood changes over time
• Sonographic features vary over time
○ Acute: Highly echogenic perinephric mass
○ Subacute: Partial liquefaction, echogenic debris,
retractile clot with thick septa
○ Chronic: May be almost anechoic
• Useful to assess perfusion in compressed kidney
• Sometimes reveals etiologies such as pseudoaneurysm
TOP DIFFERENTIAL DIAGNOSES
• Lymphoma infiltration
• Cystic lymphangioma
KEY FACTS
• Perinephric abscess
PATHOLOGY
• Causes include trauma, renal biopsy, renal cyst or tumor
rupture, anticoagulation, aneurysm rupture
CLINICAL ISSUES
• Treatment varies with etiology
• Hematoma without underlying significant pathology
usually resolves spontaneously
• Flank pain, often severe, palpable mass, shock
• Diminished hematocrit may prompt evaluation
• Subcapsular hematoma may cause hypertension
DIAGNOSTIC CHECKLIST
• Must identify underlying etiology in spontaneous
perinephric hematoma to exclude malignancy
(Left) Transverse color
Doppler US of a 6 year old
after stent placement
shows a grossly enlarged renal
contour st due to large
echogenic perinephric
hematoma. The relatively
hypoechoic kidney is seen in
the center of the mass ,
demonstrating how
hyperechoic acute blood can
obscure normal structures.
(Right) Transverse color
Doppler US shows a large,
spontaneous perinephric
hematoma with mixed
echogenicity . Note occult
RCC must be considered in
spontaneous hemorrhage.
(Left) Longitudinal US in a
young man with left flank pain
after collision during a soccer
game illustrates a thick,
irregular soft tissue rind of
blood surrounding the left
kidney. (Right) CT confirms an
extensive perinephric
hematoma in the same
patient, with associated renal
lacerations .
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