Differential Diagnosis for a 35 x 34 x 33 mm Isoechoic Structure in the Anterior Left Hepatic Lobe

• Single Most Likely Diagnosis
  • Focal Nodular Hyperplasia (FNH): This is a common benign liver lesion that is often isoechoic on ultrasound and can be found in the hepatic lobes. Its size and location are consistent with the description provided.
• Other Likely Diagnoses
  • Hepatocellular Adenoma: Although less common than FNH, hepatocellular adenomas are benign liver tumors that can appear isoechoic on ultrasound. They are more likely to be associated with symptoms or complications but can be asymptomatic.
  • Hemangioma: The most common benign liver lesion, hemangiomas are typically hyperechoic on ultrasound due to their vascular nature. However, smaller hemangiomas can appear isoechoic, making them a consideration in the differential diagnosis.
  • Regenerative Nodules: These can occur in the setting of chronic liver disease and may appear as isoechoic lesions on ultrasound. Their presence would suggest underlying liver pathology.
• Do Not Miss Diagnoses
  • Hepatocellular Carcinoma (HCC): Although less likely given the isoechoic nature, HCC is a critical diagnosis to consider due to its potential for malignancy and the need for prompt treatment. Risk factors such as cirrhosis or chronic hepatitis B/C infection would increase the likelihood.
  • Metastasis: Liver metastases from other primary cancers can appear as isoechoic lesions, especially if they are small. A history of malignancy elsewhere would heighten suspicion.
• Rare Diagnoses
  • Biliary Hamartoma (Von Meyenburg Complex): These are rare, benign lesions that can appear as small, isoechoic nodules on ultrasound. They are typically incidental findings.
  • Intrahepatic Cholangiocarcinoma: A rare malignancy of the bile ducts within the liver, which could potentially present as an isoechoic mass, although this would be uncommon.
  • Liver Abscess: Although typically hypoechoic or with a complex appearance due to the presence of pus, a liver abscess could potentially appear isoechoic, especially in early stages or if partially treated. Clinical context (e.g., fever, recent travel) would be crucial.