Differential Diagnosis for Liver Cyst

• Single most likely diagnosis:
  • Simple hepatic cyst: This is the most likely diagnosis given the description of a small, homogeneous, and well-defined cyst in the left hepatic lobe without any signs of complexity such as septations, mural nodules, or significant wall thickening.
• Other Likely diagnoses:
  • Hepatic pseudocyst: Although less common, a pseudocyst could present similarly but is often associated with a history of pancreatitis or trauma, which is not mentioned here.
  • Biliary hamartoma (von Meyenburg complex): These are small, benign lesions that can appear as cystic structures but are usually multiple and often too small to be detected by ultrasound.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Hydatid cyst: Although rare in many parts of the world, hydatid cysts can present as simple cysts and are caused by the parasite Echinococcus. They can be life-threatening if ruptured or if they cause significant compression of adjacent structures.
  • Cystic metastasis: While the primary description does not suggest malignancy, it's crucial to consider metastatic disease, especially in patients with a known history of cancer, as some metastases can appear cystic.
• Rare diagnoses:
  • Polycystic liver disease: Characterized by multiple cysts of varying sizes, this condition is less likely given the presence of only a single cyst in the provided description.
  • Caroli's disease: A rare congenital disorder involving non-obstructive dilatation of the intrahepatic bile ducts, which can sometimes appear as cystic structures. However, it typically involves more extensive bile duct abnormalities and is not suggested by the normal vascular landmarks and lack of intrahepatic biliary dilatation in this case.