American Urological Association - Simple Cortical Cyst
Simple Cortical Cyst
- Most common cystic lesion of the kidney.
- Sporadic and mostly clinically inconsequential.
- Mostly seen incidentally in radiology or in autopsy.
- Clinical: Rare before age of 40; increase with age thereafter.
- May be multiple and large in older patients; otherwise, solitary simple cysts (as the name implies!) (image A).
- Unilocular cyst with smooth lining and contain clear fluid.
- Cyst lined by a flattened or attenuated layer of cells (image B), or may lack an epithelial lining (denuded).
- May be surrounded by fibrosis.
- Cystic nephroma/mixed epithelial and stromal tumor: Cysts with hobnailed cells + cellular stroma ("ovarian type stroma").
- Cystic RCC: Multilocular cyst or partially cystic and lined by clear cells.