Differential Diagnosis

• Single most likely diagnosis
  • Chronic liver abscess: Given the description of a "chronic echogenic likely inflammatory or infectious cystic lesion of the right lobe of the liver," a chronic liver abscess is a plausible diagnosis. The chronic nature and the location in the liver support this possibility.
• Other Likely diagnoses
  • Hepatic cyst: Although the description leans towards an inflammatory or infectious cause, a hepatic cyst could also present as an echogenic cystic lesion, especially if it becomes complicated (e.g., infected or hemorrhagic).
  • Focal fatty sparing or infiltration: The mention of resolution or partial resolution of fatty infiltration of the liver, along with an echogenic lesion, could suggest an area of focal fatty sparing or infiltration, which might appear as a cystic lesion on imaging.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Hepatocellular carcinoma (HCC): Although less likely given the description, HCC can present as a cystic lesion, especially in the context of chronic liver disease. Missing this diagnosis could have severe consequences.
  • Liver metastasis: Metastatic disease to the liver can present in various ways, including as cystic lesions. Given the potential for malignancy, this diagnosis should not be overlooked.
  • Hydatid cyst: Echinococcal (hydatid) cysts can appear as cystic lesions in the liver and can be chronic. They are less common in some regions but can be deadly if ruptured or if they cause significant organ compromise.
• Rare diagnoses
  • Biliary cystadenoma or cystadenocarcinoma: These are rare tumors of the bile duct that can present as cystic lesions in the liver. They are important to consider due to their potential for malignancy.
  • Polycystic liver disease: While this condition typically presents with multiple cysts, a solitary large cyst could be considered in the differential, especially if there's a family history or other suggestive findings.
  • Amoebic liver abscess: In endemic areas or with a history of travel, an amoebic liver abscess could present similarly to a chronic bacterial abscess, though it's less common in many parts of the world.