← All patterns
Solid enhancing renal mass
GUCT / MRI
An enhancing (>20 HU) soft-tissue renal lesion. Presence of macroscopic fat and enhancement pattern separate benign entities from renal cell carcinoma subtypes.
Differential
Clear cell renal cell carcinoma
common- •Avid heterogeneous enhancement with washout
- •Necrosis/haemorrhage; renal vein/IVC tumour thrombus
- •Signal drop on opposed phase (intracellular lipid)
Papillary renal cell carcinoma
common- •Homogeneous but LOW-level enhancement
- •T2 hypointense, may show haemorrhage/calcification
Angiomyolipoma
less-common- •Macroscopic fat (negative HU / India-ink artefact)
- •Enhancing vascular and muscle components
- •Multiple/bilateral in tuberous sclerosis
Oncocytoma
less-common- •Homogeneous enhancement with central stellate scar
- •Spoke-wheel vascularity; cannot be reliably distinguished from RCC
Lymphoma / metastasis
rare- •Multiple hypoenhancing masses or diffuse infiltration
- •Retroperitoneal adenopathy; known primary
Fat-poor angiomyolipoma
rare- •T2 hypointense, homogeneous, no visible macroscopic fat
- •Often indistinguishable from RCC on imaging
Key discriminators
- •Macroscopic fat (AML) vs none
- •Degree of enhancement (avid clear cell vs low-level papillary)
- •T2 signal (papillary and fat-poor AML dark)
- •Central scar (oncocytoma, non-specific)
- •Vascular invasion / multiplicity
Work-up / next steps
- 1.Multiphase renal-protocol CT or MRI with washout assessment
- 2.Chemical-shift MRI to detect fat
- 3.Percutaneous biopsy for indeterminate solid masses
- 4.Urology referral / apply nephrometry scoring for surgical planning
References
- Radiopaedia: Renal cell carcinoma.
- Kang SK et al. Solid renal masses. RadioGraphics.
Educational clinical decision support only. This differential does not make a diagnosis, is not a medical device, and must never substitute for interpretation by a qualified radiologist correlated with the full clinical picture and prior imaging.