Papillary renal cell carcinoma

Papillary renal cell carcinoma
Diagnosis in short
Papillary renal cell carcinoma. H&E stain.
LM	cuboidal or low columnar cells (simple or pseudostratified) on papillae, interstitial foam cells in the vascular cores
Subtypes	type 1, type 2, eosinophilic variant
LM DDx	clear cell renal cell carcinoma, clear cell papillary renal cell carcinoma, metanephric adenoma (esp. solid PRCC type 1), collecting duct carcinoma (esp. PRCC type 2), renal papillary adenoma
Gross	may be multifocal, must be >0.5 cm (otherwise renal papillary adenoma)
Site	kidney - see kidney tumours
Associated Dx	acquired renal cystic disease (end-stage renal disease)
Prevalence	relatively common
Clin. DDx	other kidney tumours

Papillary renal cell carcinoma, abbreviated PRCC, PaRCC and papillary RCC, is the second most common type of renal cell carcinoma.

General

• Often subclassified into type 1 and type 2 -- see microscopic.
  • Type 1 and Type 2 are different on a cytogenetic and molecular basis.

Epidemiology

• Associated with acquired renal cystic disease.
• May be familial.

Microscopic

Features:

• Cuboidal or low columnar cell in papillae.
• Interstitial foam cells in vascular cores - key feature.
  • Most sensitive and specific feature of PRCC.
• Highly vascular.

Size criterion:

• Papillary lesions must be >0.5 cm to be called carcinoma; smaller lesions (<=0.5 cm) are called papillary adenomas.

Mnemonic HIP: highly vascular, interstitial foam cells, papillae.

DDx:

• Clear cell RCC.
  • Papillary: +histiocytes, +intracellular hemosiderin, CK7+.
• Clear cell papillary renal cell carcinoma.
• Metanephric adenoma - esp. solid PRCC type 1.
• Collecting duct carcinoma - esp. PRCC type 2.
• Renal papillary adenoma.

Images

• 

  PaRCC - intermed. mag. (WC/Nephron)

• 

  PaRCC - high mag. (WC/Nephron)

• 

  PaRCC - very high mag. (WC/Nephron)

Histological subtyping

Generally accepted subtypes:

• Type 1 - single layer of cells on basement membrane - most important.
  • Usually low grade nuclear features, i.e. low Fuhrman grade.
  • Other characteristics:
    • Clear cytoplasm.
    • Foamy macrophages - common.
    • Cells smaller.
• Type 2 - pseudostratification of cells - most important.
  • Usually high grade nuclear features, i.e. high Fuhrman grade.
  • Other characteristics:
    • Eosinophilic cytoplasm.
    • Foamy macrophages - uncommon.
    • Cells larger.

Another subtype:

• Oncocytic - oncocytic cytoplasm.
  • Extremely rare ~ largest series is 12 cases.

IHC

Features:

• AMACR +ve.
• HMWCK (34betaE12) +ve.
• Panker (AE1/AE3) +ve.
• CK7 +ve ~90% of type 1, 20% of type 2.

More reading:

• PaRCC (e-immunohistochemistry.info).

Type 1 vs. Type 2:

• CK7:
  • type 1 ~ 100%.
  • Type 2 ~ 19%.
• CK19:
  • type 1 ~ 100%.
  • Type 2 ~ 53%.

Metanephric adenoma vs. PaRCC type 1:

• AMACR +ve.
• WT-1 -ve.
• CD57 -ve.

Molecular

Features:

• Sporadic: trisomies 7, 16, 17.
• Familial: trisomy 7.
  • Chromosome 7 = location of MET gene.

Note:

• Not used for diagnosis.

Sign out

KIDNEY, RIGHT, NEPHRECTOMY:
- PAPILLARY RENAL CELL CARCINOMA, ONCOCYTIC -- SEE COMMENT;
- FUHRMANN GRADE 2;
- SURGICAL MARGINS NEGATIVE;
- PLEASE SEE TUMOUR SUMMARY.

COMMENT:
The oncocytic variant of papillary renal cell carcinoma (RCC) is uncommon and not widely
recognized as a subtype of papillary RCC.  The prognostic significance of the oncocytic 
cytoplasm is uncertain.[1]  The histomorphology in this case is compatible with a type 1 
papillary RCC.

1. Ann Diagn Pathol. 2006 Jun;10(3):133-9.

See also

• Kidney tumours.