Oncocytoma

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

Clinical features

• 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 metastasise

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 features

• Incidental (50%)
• Loin pain