Comments: 

• The relatively pure fibrous tissue in a tumor capsule is distinct from the mixed fibrous tissue (containing bile ducts, blood vessels, and inflammatory cells in addition to collagen) around background cirrhotic nodules. This mixed fibrous tissue represents condensation of cirrhotic scarring.
• A rim of increasing enhancement in the portal venous phase or delayed phase around a mass at imaging is termed “capsule appearance". It may represent a true tumor capsule or a pseudocapsule. 
  • Imaging does not reliably differentiate between a true tumor capsule and a pseudocapsule.
  • The distinction between a true tumor capsule and pseudocapsule can only be made at pathology. 
• In at-risk patients, “capsule” appearance has high positive predictive value for HCC, regardless of whether rim of enhancement represents a true tumor capsule or a pseudocapsule.