Renal cell carcinoma (RCC)

Clinical features

  • Rare (less than 5% of paediatric renal tumours)
  •  Paediatric associated subtypes:
    • Renal medullar carcinoma
    • Xp11.2 associated RCC represent 20% of renal cell carcinomas at paediatric and adolescent ages
      • Special type of renal cell carcinoma
      •  More frequent in children
      •  Associated with different translocations involving chromosome Xp11.2.
    • t(6;11) translocation RCC
  • In tuberous sclerosis setting (TSC)
    • Kidney manifestations of TSC: angiomyolipomas, polycystic kidney disease, oncocytomas, RCC
    • RCC in TSC: clear cell type; papillary; chromophobe
      • Few cases reported
      • Neoplastic cells with granular eosinophilic abundant cytoplasm
      • Differential diagnosis between RCC NOS, oncocytoma and chromophobe RCC can be a challenge
      • HMB45:negative
      • AE1/AE3: positive
  • Neuroblastoma associated RCC
    • Very  unusual-2.5% of renal cell carcinomas in young patients
    • Described in survivors of childhood neuroblastoma
  • High-risk tumour (SIOP-2001 revised working classification of renal tumours of childhood)

 

Fig 10 a - Renal cell carcinoma- abundant clear micro vacuolated cytoplasm with ill-defined borders and macrophages with hemosiderin pigment, 
Fig 10 b – Renal Cell Carcinoma- Flat sheets and papillary aggregate of tumor cells. Central round nuclei and prominent nucleoli (H&E)
Fig 10c - Renal Cell Carcinoma
Fig 11 a– Xp11.2 associated RCC- Large polygonal eosinophilic or clear neoplastic cells with prominent nucleoli in a papillary pattern. 
Fig 11b - Psammoma bodies are frequent (H&E)

 

 

  • Clear cell RCC
    • Flat sheets and trabecular, papillary aggregated tumour cells mixed with stromal components and capillaries
    • Numerous single cells
    • Cells with central or eccentric  round nuclei
    • Prominent nucleoli in high-grade tumours
    • Intranuclear vacuoles common
    • Pale, vacuolated or granular cytoplasm
    • Cytoplasmic fragility with ill-defined borders
    • High nuclear grade frequent
    • Background with blood and necrosis is frequent
    • Magenta-staining basement membrane-like material
  • RCC in children, Xp11.2 associated tumours
    • Large polygonal eosinophilic or clear neoplastic cells
    • Prominent nucleoli
    • Intracytoplasmic hyaline bodies and intranuclear inclusions
    • Papillary pattern more frequent
    • Psammoma bodies are frequent
  • t (6;11) (p21;q12)-No reports on cytological features have been described.

 

Immunocytochemistry

  • Clear cell RCC:
    • RCC: positive
    • AE11AE3: positive
    • Vimentin: positive
    • Pax8: positive
    • EMA: positive
    • CD10: positive
    • Ck7: negative
    • AMACR: negative
    • Alpha-inhibin: negative
    • Melan A: negative
  • Xp11.2 RCC associated tumours:
    • Renal cell carcinoma marker antigen: positive
    • CD10: positive
    • EMA: positive (focal)
    • Vimentin: positive (focal)
    • TFE3: positive ( nuclear labelling)
    • AE1AE3: usually negative
    • S-100 protein, desmin: negative 
  • t(6;11)-related RCC:
    • HMB45: positive
    • Melan A: positive
    • Cytokeratin’s: negative

 

Genetic studies

Contrary to what is observed in adults, childhood RCC is less frequently associated with mutations and deletion of the VHL genes

  • Xp11.2 associated tumours
    • t(X;1)(p11.2;q21)-fusion TFE3 gene with PRCC gene
    • t(X;1)(p11.2;p34)-fusion TFE3 gene with the NonO(p54 nrb)
    • t(X;17) (p11.2;q25)-Balanced translocation that fuses TFE3 gene with the ASPL gene-(same translocation of alveolar soft part sarcoma, in this last tumour it is unbalanced translocation is present).
  • t(6;11)-associated RCC
    • t(6;11)(p21;q12)

 

Differential diagnosis

  • Adrenal cortical cell tumours
    • Some cases are indistinguishable by histological means alone
    • Alpha-inhibin: positive
    • Melan A: positive
    • Vimentin: positive
    • EMA: negative
    • RCC: negative
  • Hepatic cells
    • Can be confused with granular cells in clear cell RCC
    • Better defined cytoplasmic borders
    • Cytoplasmic iron
    • Hep-par 1:positive
    • Arginase :positive

 

Main points

  • Xp11.2-associated tumours comprise a significant percentage of all renal carcinomas in children
  • Renal cell carcinomas are rare in childhood and comprise less than 5% of paediatric renal tumours
  • Cases of renal cell carcinoma arising in Wilms’ tumours have been described
  • Association with Von-Hippel-Lindau syndrome is less frequent in childhood

 

 

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