Benign Renal Tumours

Oncocytoma

  • Made up of oncocytes (epithelial cells with an excess amount of mitochondria)

Clinical presentation

  • Incidental (85%)
  • Loin pain
  • Haematuria

Investigations

  • CT - spoke wheel pattern
  • Biopsy
    • Mahogany brown with a central stellate scar
    • Very pink and granular cytoplasm
    • Aggregates of eosinophilic cells, mitosis is rare and cells packed with mitochondria
    • Can be uncertain, similarities to chromophobe RCC

Management

  • Observation 4-5 years if biopsy proven
  • Not known to metastasize

Angiomyolipoma

  • Blood vessels, immature smooth muscle, and fat

Aetiology

  • 80% sporadic in middle aged females
  • 20% in association with tuberous sclerosis
    • 80% of TS patients develop AML

Clinical presentation

  • Incidental (50%)
  • Loin pain
  • Haematuria
  • Mass
  • Wunderlich's syndrome - 10%, massive retroperitoneal bleed

Investigations

  • USS - bright echo pattern
  • CT - fatty tumour of low density

Management

  • 4 cm is considered cut off
  • Elective - embolisation, partial nephrectomy
  • Emergency - embolisation, emergency nephrectomy