Adrenal cysts

Endothelial cyst

• Vascular cyst
• Endothelial lining
• 45% of adrenal cysts
• 2/3 in females
• 8% bilateral
• May have residual adrenocortical tissue in wall 

Hemorrhagic cyst

• Pseudocyst
• 39% of adrenal cysts
• Middle-aged women 
• Seen in Beckwith-Wiedemann syndrome
• Originally would have been an endothelial cyst, that underwent hemorrhage, and secondary fibrosis or hemosiderin deposition

Parasitic cyst

• Echinococcal
• Asymptomatic
• Imaging types:
  1. Simple cysts with no internal architecture
  2. Water lily sign with separation of membrane layers
  3. Complex internal septa and floating debris
  4. Solid walls and calcification +
  5. Solid walls and calcification +++

Epithelial lined cyst

• True cyst
• Rare
• Mesothelial origin
• Retention cysts, embryonal cysts or arise from adenomas

Lymphangioma 

• Rare
• Thin walled, smooth with flattened endothelial cells