Differential Diagnosis for the 22-year-old Woman with a Hepatic Lesion

• Single most likely diagnosis:

  • E. Hepatic adenoma: This is the most likely diagnosis given the patient's age, sex, and the use of oral contraceptives, which are known risk factors for hepatic adenomas. The appearance on CT scan, initially hypodense and becoming irregularly enhancing after contrast administration, is also consistent with a hepatic adenoma.

• Other Likely diagnoses:

  • C. Hepatocellular carcinoma: Although less likely in a young woman without a history of liver disease, hepatocellular carcinoma (HCC) can occur in non-cirrhotic livers, especially with certain risk factors. The imaging characteristics could fit HCC, but the patient's demographics and lack of liver disease history make it less probable.
  • D. Cholangiocarcinoma: This is a malignancy of the bile duct and could present as a mass in the liver. However, it is less common in young individuals without risk factors such as primary sclerosing cholangitis or a history of exposure to certain carcinogens.

• Do Not Miss diagnoses:

  • A. Ampullary cancer and B. Gallbladder cancer: While these are less likely given the location of the lesion in the right hepatic lobe and the lack of specific symptoms or risk factors, any malignancy in the biliary tract or pancreas could potentially present with a liver mass. Missing these diagnoses could have significant implications for treatment and prognosis.
  • C. Hepatocellular carcinoma (also listed under Other Likely diagnoses): Given its potential for aggressive behavior and the importance of early detection for treatment, HCC should not be missed, even if it seems less likely based on the patient's profile.

• Rare diagnoses:

  • Other rare liver tumors: Such as hepatoblastoma, epithelioid hemangioendothelioma, or inflammatory pseudotumor, could present with similar imaging findings but are much less common and would be considered only after more common diagnoses are ruled out.
  • Metastatic disease: Although the patient does not have a known primary malignancy, metastases to the liver from other cancers could present as a solitary lesion. This would be unusual in a young woman without a known cancer history but should be considered in the differential diagnosis.