Renal cell carcinoma
|
Solid to partially cystic mass that can be hyper, iso, or hypoechogenic
compared with the normal renal parenchyma.
The pseudocapsule of the tumor is sometimes seen as a hypoechoic halo
sign 23.
|
Lesions demonstrate soft-tissue attenuation on non-enhanced CT.
On contrast-enhanced CT, they are usually enhanced less than the normal
cortex. Smaller lesions display homogeneous enhancement, whereas larger
lesions have irregular enhancement due to areas of necrosis.
Degrees of calcification are seen in about 30% of cases
24.
|
Lesions are heterogeneous on T1W. Clear cell RCC is hyperintense and
papillary RCC is hypointense on T2W 25.
A hypointense rim between the tumor and the normal renal parenchyma
suggests tumor pseudocapsule 26.
|
Lesions usually demonstrate mild FDG avidity 27.
|
Renal Lymphoma
|
Single or multiple hypoechoic masses located within renal parenchyma
with scarce internal vascularity. Varying degrees of hydronephrosis
might also be seen 28.
|
Wide range of findings including multiple poorly-enhanced masses with
significant retroperitoneal lymphadenopathy (most common), single
homogeneous and hypodense mass without cystic change, retroperitoneal
nodal mass invasion with or without hydronephrosis, diffuse infiltration
without evidence of obvious mass, perirenal mass, or nodule.
Atypical features include calcification, hemorrhage, necrosis, cystic
change, or heterogeneous lesions 27-29
|
T1W shows hypointense signal and T2W exhibits iso-to- hyperintense
signal compared with normal parenchyma.
Contrast-enhanced T1 is indicative of poor and delayed (in some cases)
enhancement 28.
|
FDG uptake by the lymphoma lesions was much higher than the FDG uptake
by the renal cell carcinomas 30.
|
Erdheim-Chester disease |
Ultrasound demonstrates
retroperitoneal and perirenal infiltration 31.
Stenosis of renal arteries and decreased/ absent flow might be seen on
duplex ultrasound due to perivascular fibrosis 32. |
Symmetric homogeneous hypo-enhanced perinephric soft tissue that encases
the kidneys, known as “hairy kidney” appearance. Hydronephrosis,
calyceal dilatation, and bilateral ureteral encasement may also be seen
in some cases 2. |
T1 and T2 imaging show perinephric
soft tissue with isointense signal relative to muscle and mild
enhancement after IV contrast 27. |
FDG PET/ CT shows
increased uptake in the involved sites )due to increased glucose
metabolism by histiocytes) 27
|
Multiple myeloma |
|
Multiple enhancing perinephric nodules and
masses (most common); focal renal masses can also be observed
27. |
|
Intense FDG uptake by the masses
27. |
Metastatic Lesion
|
Multiple metastases usually appear as small, poorly marginated,
hypoechoic masses 33.
|
Multiple, small, and bilateral lesions predominantly confined to the
renal parenchyma.
At CT and MR imaging, the contrast-enhancement characteristics vary
according to the site of the primary tumor27.
|
Multiple, small, and bilateral lesions predominantly confined to the
renal parenchyma. Signal intensity depends on the primary site
27.
|
Increased FDG uptake; greater than that of the adjacent renal
parenchyma34.
|