Chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma
Diagnosis in short
Eosinophilic variant of chromophobe renal cell carcinoma. H&E stain.
LM	pale cytoplasm, with wisps of eosinophilic material, perinuclear clearing (a pale halo surrounds the nucleus), periphery of cell distinct (cell membrane is easy to discern -- plant cell-like)
Subtypes	classic, eosinophilic variant
LM DDx	clear cell renal cell carcinoma (classic), renal oncocytoma, clear cell renal cell carcinoma eosinophilic variant
Stains	Hale's colloidal iron (Mueller-Mowry stain) +ve
IHC	CK7 +ve cell membrane, CD117 +ve, vimentin -ve
Gross	brown/tan, lacks central scar
Grossing notes	total nephrectomy for tumour grossing, partial nephrectomy grossing
Site	kidney - see renal tumours
Syndromes	Birt–Hogg–Dubé syndrome
Prevalence	relatively common
Clin. DDx	other renal tumours
Treatment	surgical resection

Chromophobe renal cell carcinoma, abbreviated ChRCC, is a relatively common form of renal cell carcinoma.

General

• Least common of the common types of RCC (clear cell RCC, papillary RCC, chromophobe RCC).
• Fuhrman grading for this entity is controversial, as it does not appear to have any predictive value.
• May be associated with Birt–Hogg–Dubé syndrome.

There are two subtypes:

• Classic.
• Eosinophilic variant.

Gross

• Tan, light-brown.
• Solitary, usually.
• Well-circumscribed.

Image:

• Chromophobe RCC (flickr.com).

Microscopic

Classic

Features - classic type (3 P's mnemonic):

• Pale cytoplasm, with wisps of eosinophilic material; the cells are not completely clear, they have "cobwebs".
• Perinuclear clearing, i.e. a pale halo surrounds the nucleus - key feature.
• Periphery of cell distinct, i.e. cell membrane is easy to discern.

Notes:

• May have psammoma bodies.
• May be described as "plant-like"; plant cells have (thick) cell walls.
• The perinuclear clearing is often somewhat patchy, i.e. it is usually not present in very tumour cell.

DDx:

• Clear cell RCC (classic).
  • Perinuclear clearing is not seen in clear cell RCC.
  • ChRCC has wisps in the cytoplasm.

Eosinophilic variant

Features - eosinophilic variant:

• Eosinophilic (finely granular) cytoplasm.
• Perinuclear clearing - key feature.
• Periphery of cell distinct.
• Smaller cells than classic subtype.

Notes:

1. May have psammoma bodies.

DDx:

1. Oncocytoma - particularly the eosinophilic variant.
   • IHC may be useful to differentiate (CK7: oncocytoma = cytoplasm +ve, chromophobe = cell membrane +ve).
   • A comparison based on histomorphology: Tabular comparison between ChRCC & oncocytoma.
     • Oncocytoma typically has: no perinuclear clearing, no raisinoid nuclei, no binucleation.
2. Clear cell RCC, eosinophilic variant.
   • Perinuclear clearing is not seen in clear cell RCC.
   • ChRCC has wisps in the cytoplasm.

Image

• 

  Eosinophilic chromophobe RCC. (WC/Nephron)

www:

• Chromophobe RCC - several images (upmc.edu).

Stains

• Hale's colloidal iron +ve (blue granular cytoplasmic).
  • Oncocytoma -ve.

Note:

• This seems to be a difficult stain to get working.

Images

• ChRCC Hale's colloidal iron - several images (nature.com).
• ChRCC Hale's colloidal iron (ultrapath.org).
• ChRCC Hale's colloidal iron (diagnosticpathology.org).

IHC

• CK7 +ve cell membrane.
  • Useful for differentiating from oncocytoma.
• CD117 +ve.
• Vimentin -ve.

Uncommon stains for ChRCC versus oncocytoma:

• PAX2 -ve .
  • ChRCC 10 of 11 -ve versus Oncocytoma 3 of 23 -ve.
• Amylase α-1A -ve.

ChRCC versus clear cell RCC

ISUP recommends:

• CD117 +ve.
  • -ve in CCRCC.
• CAIX (carbonic anhydrase CA IX) -ve.
  • +ve (strong membranous) in CCRCC.
• CK7 +ve.
  • -ve in CCRCC.

Molecular

• Extensive aneusomy (monosomy?):
  • Loss of chromosomes: 1, 2, 6, 10, 13, 17, 21.

Sign out

KIDNEY, RIGHT UPPER POLE, PARTIAL NEPHRECTOMY:
- CHROMOPHOBE RENAL CELL CARCINOMA.

COMMENT:
The sections show a mix of clear cells with wispy cytoplasm, and cells with eosinophilic
cytoplasm and perinuclear halos. There are no true papillae. 

Stains and immunostains:
Positive: CK7, CAM5.2, EMA, pankeratin, CD117, colloidal iron.
Negative: AMACR, CD10, CD68, RCC, vimentin.

See also

• Kidney tumours