Clear cell tubulopapillary renal cell carcinoma

Definition

This is a proposed category of low-grade renal cell tumour not recognised in the WHO 2004 classification.

Synonyms

Epidemiology

This tumour accounts for about 1% of all adult renal tumours.  It occurs across a wide adult age range with a mean of 60 years.  Male and female frequency are equal.  10% of cases are bilateral.  

Macroscopic appearances

Most tumours are cystic and small (mean 2.4 cm).  A minority are multifocal.  

Histopathology

The majority of tumours are multicystic.  There is a capsule, usually thick and circumferential.  The majority of cases have a fibrotic stroma with embedded tumour cells and most include smooth muscle fibres.  The cysts contain serosanguinous fluid for colloid-like material.  The cysts are lined by a single layer of cuboidal cells with eosinophilic or clear cytoplasm.  Almost all cases include tubules and acini with a similar lining.  The nuclei of the cuboidal cells tend to be located towards the apical aspect of the cells.  Most cases include papillae, which rarely may dominate, again lined by similar cells.

Perirenal invasion, renal sinus invasion, vascular invasion, necrosis and sarcomatoid dedifferentiation are not seen.

Some patients have a concomitant clear cell renal cell carcinoma.  

Immunohistochemistry

  CK7 36/361  
Carbonic anhydrase 9 34/361
CD10 6/361
AMACR 0/361
TFE3 0/361
   

 

Cytogenetics

There is an absence of 3p deletion and VHL gene mutation or methylation of the gene  promotor region.

Differential diagnosis

Prognosis

Almost all patients are tumour-free two years after nephrectomy.

References

1 Aydin H, Chen L, Cheng L, Vaziri S, He H, Ganapathi R, et al. Clear cell tubulopapillary renal cell carcinoma: a study of 36 distinctive low-grade epithelial tumors of the kidney. Am J Surg Pathol. 2010 Nov;34(11):1608-21.

This page last revised 12.12.2010

©SMUHT/PW Bishop