Diagnostic Ultrasound - Abdomen and Pelvis

Cystic Renal Mass
○ Associated with contralateral renal abnormalities such as
ureteropelvic junction obstruction and vesicoureteric
reflux
• Cystic Renal Cell Carcinoma
○ 15% of RCC are cystic
○ Unilocular or multilocular unencapsulated cystic lesion
○ Thin and thick septa and solid components
○ ± tumor nodules, ± tumor necrosis
• Localized Cystic Renal Disease
○ Cluster of simple cysts, not encapsulated, normal
intervening parenchyma
• Renal Abscess
○ Thick walled with internal debris and septation
○ Perinephric extension
○ Clinical picture of infection
• Renal Hematoma
○ History of trauma, intervention, surgery, bleeding
diathesis
○ Spontaneous bleeding from renal mass such as RCC or
angiomyolipoma
○ Avascular complex cystic lesion of variable echogenicity
in kidney and perinephric space
Helpful Clues for Less Common Diagnoses
• Multilocular Cystic Nephroma (MLCN)
○ Encapsulated multilocular cystic lesion
○ Thin and thick septa, lacking solid nodules
○ Classically herniating into renal pelvis or renal vein
○ Unilateral, middle-aged women
• Mixed Epithelial and Stromal Tumor
○ Benign tumor of perimenopausal women
○ Similar appearance to MLCN
• Primary Renal Synovial Sarcoma
○ Typically solid but may have large cystic components
○ Rare tumor with poor prognosis
• Lymphangioma
○ Benign
○ Asymptomatic
○ Unilateral or bilateral renal sinus or perinephric fluidfilled
lesions
○ Unilocular or multilocular
• Perinephric Collection
○ Results from ruptured hydronephrosis or pyonephrosis
or ruptured cyst
○ Occasionally direct extension of peritoneal or
retroperitoneal infection
○ Fluid collection outside renal parenchyma
– May cause indentation or distortion of renal contour
• Tuberous Sclerosis
○ Autosomal dominant inherited disease with
developmental delay, seizures and multiple hamartomas
○ Renal lesions include multiple cysts and
angiomyolipomas
○ Risk of renal cell carcinoma not increased but develops at
a younger age
• von Hippel-Lindau Disease
○ Autosomal dominant disease with multiorgan
manifestations
○ Renal lesions include multiple renal cysts and multifocal
renal carcinoma (clear cell most common)
• Arteriovenous Fistula/Malformation; Intrarenal
Aneurysm
○ Tubular, serpiginous fluid filled lesions ± aneurysms ±
collateral vessels
○ Use color and spectral Doppler to prove vascular nature
○ Acquired more common than congenital
○ Present with hematuria and flank pain or may be
asymptomatic
• Congenital Megacalyces
○ Rare nonobstructive enlargement of calyces
○ May be associated with megaureter
○ Usually unilateral
• Renal Lymphoma or Metastases
○ Lymphoma may be hypoechoic
○ Metastases may be cystic
○ Diagnosis based on presence of other lesions or biopsy
Differential Diagnoses: Kidney
Simple Renal Cyst
Complex Cysts: Hemorrhagic, Infected, or
Proteinaceous
(Left) Transverse oblique
ultrasound shows multiple
simple renal cortical cysts .
Two are exophytic. All cysts
are round, thin walled,
anechoic with posterior
acoustic enhancement st.
(Right) Longitudinal
ultrasound of a renal
transplant is shown. The cyst
ſt in the upper pole is
complex because there is a
thin septum st with low-level
echoes in the anterior
component. This requires
further evaluation with color
Doppler and contrastenhanced
CT, MR, or
ultrasound.
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