Papillary renal cell carcinoma
Papillary renal cell carcinoma (pRCC) is one of the subtypes of renal cell carcinoma.
This subtype may account 13-20% of all renal cell cancer. There is slightly increased male predilection.
As with other types of renal cell cancer, most are asymptomatic and incidentally discovered.
There are two subtypes described according to morphology 7:
- have papillae covered by a single layer of cuboidal or low columnar cells with scanty cytoplasm and low-grade nuclei
- carry a better prognosis than type II tumours
- are of a higher nuclear grade and contain more than one layer of cells with abundant eosinophilic cytoplasm
- although mostly unilateral, this subtype is considered the most common to result in bilateral renal cell cancers 1
While it has been described to have a tendency to present at a lower stage, it still has a distinct potential for progression and aggressive behaviour 4.
Although there is no absolute rule, in general, papillary renal cancers at diagnosis tends to have a smaller mean diameter and be at a lower stage. The imaging features of type 1 and type 2 tumours may overlap.
Generally tends to be hypoechoic on ultrasound 9.
On CT, many papillary renal cell cancers do not enhance, indicating that assessment of enhancement alone as being insufficient for differentiation from hyper-attenuating cysts 8. Contrast enhancement, in general, tends to be less intense.
Smaller lesions tend to be homogeneous is attenuation with larger tumours tending to be heterogeneous.
- T1: hypointense
- T2: hypointense
- T1 C+ (Gd): contrast enhancement tends to be less intense than in the more common clear cell RCC variant
- DWI: restricted diffusion may be useful for differentiating from a hemorrhagic cyst
- frequently shows a pseudo capsule
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- 2. Ronnen EA, Kondagunta GV, Ishill N et-al. Treatment outcome for metastatic papillary renal cell carcinoma patients. Cancer. 2006;107 (11): 2617-21. doi:10.1002/cncr.22340 - Pubmed citation
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- 7. Delahunt B, Eble JN, McCredie MR et-al. Morphologic typing of papillary renal cell carcinoma: comparison of growth kinetics and patient survival in 66 cases. Hum. Pathol. 2001;32 (6): 590-5. doi:10.1053/hupa.2001.24984 - Pubmed citation
- 8. Egbert ND, Caoili EM, Cohan RH et-al. Differentiation of papillary renal cell carcinoma subtypes on CT and MRI. AJR Am J Roentgenol. 2013;201 (2): 347-55. doi:10.2214/AJR.12.9451 - Pubmed citation
- 9. Tsuda K, Kinouchi T, Tanikawa G et-al. Imaging characteristics of papillary renal cell carcinoma by computed tomography scan and magnetic resonance imaging. Int. J. Urol. 2005;12 (9): 795-800. doi:10.1111/j.1442-2042.2005.01126.x - Pubmed citation
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