Clear cell renal cell carcinoma

Clear cell renal cell carcinoma (CCRCC) is a type of renal cell carcinoma.

Genetics

Cytogenetics
  • Alterations of chromosome 3p segments occurs in 70 – 90% of CCRCCs
  • Inactivation of von Hippel–Lindau disease (VHL) gene by gene mutation and promoter hypermethylation
  • Gain of chromosome 5q
  • Loss of chromosomes 8p, 9p, and 14q

Molecular genetics

Several frequently mutated genes were discovered in CCRCC: VHL, KDM6A/UTX, SETD2, KDM5C/JARID1C and MLL2. PBRM1 is also commonly mutated in CCRCC.

Histogenesis

CCRCC is derived from the proximal convoluted tubule.

Microscopy

Generally, the cells have a clear cytoplasm, are surrounded by a distinct cell membrane and contain round and uniform nuclei.

Microscopically, CCRCCs are graded by the ISUP/WHO as follows:[1][2]

  • Grade 1: Inconspicuous and basophilic nucleoli at ×400 magnification
  • Grade 2: Clearly visible and eosinophilic nucleoli at ×400 magnification
  • Grade 3: Clearly visible nucleoli at ×100 magnification
  • Grade 4: Extreme pleomorphism or rhabdoid and/or sarcomatoid morphology

Epidemiology
  • Most commonly affects male patients in their sixties and seventies.
  • Majority of CCRCC arise sporadically.
  • Only 2–4% of the cases presenting as part of an inherited cancer syndrome, such as Von Hippel–Lindau disease.

Images
  • Clear cell renal cell carcinoma. Macroscopy.
  • Clear cell renal cell carcinoma. HE, x100.
  • Clear cell renal cell carcinoma. Führman Grade = 1. HE, x400.
  • Grade 3: Arrows point at a clearly visible nucleolus.

References
  1. YiFen Zhang. "What is the ISUP/WHO grading system for renal cell carcinoma (RCC)?". Medscape. Updated: Jul 02, 2019
  2. Moch, H. (2016). "WHO-ISUP-Graduierungssystem für Nierenkarzinome". Der Pathologe. 37 (4): 355–360. doi:10.1007/s00292-016-0171-y. ISSN 0172-8113.
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