Home Education AUAUniversity Education Products & Resources Pathology for Urologists Kidney Renal Cell Carcinomas Multilocular Cystic Renal Cell Carcinoma

Multilocular Cystic Renal Cell Carcinoma

Image A

Image B

  • Purely cystic tumor lined by clear cells of same cytology to clear cell RCC; additional presence of solid area qualifies the tumor as clear cell RCC.
  • Alteration in VHL also present.
  • Occurs in adult patients, mean in their 50s.
  • Vast majority discovered incidentally.
  • Gross: Multicystic tumor of varying sizes with thin septae and contains clear or bloody fluid. (Should have no solid area).
  • Histology:
    • Cysts are separated by thin septae and lined by single or few layers of clear cells with low-grade nuclei (Fuhrman grade 1 or 2) (image A), (image B), (image C), & (image D).
    • Few clears cells may be seen within the septa, but there should be no sheet or solid area of clear cells.

Image C

Image D

  • No recurrence or metastasis reported, including in those few cases with extrarenal extension (pT3).
  • DDX:
    • Non-neoplastic cystic diseases of the kidney: no clear cell lining.
    • Cystic nephroma: lined by "hobnailed cells" and may have "ovarian-type stroma".
    • Cystic partially differentiated Wilms tumor: cells are primitive appearing (small blue cells) and seen in children.