A 32-year-old woman on long-term oral contraceptives undergoes MRI liver for a 4 cm incidentally detected lesion. On in-phase and opposed-phase T1-weighted sequences, the lesion shows significant signal dropout on the opposed-phase images. No central scar is seen. What is the most likely diagnosis?
- A Focal nodular hyperplasia
- B Hepatic adenoma ✓
- C Hepatocellular carcinoma
- D Hemangioma
Correct answer: B. Hepatic adenoma
Explanation
Hepatic adenoma contains intracellular lipid, which causes signal dropout on opposed-phase chemical shift MRI sequences. This finding is highly characteristic and helps differentiate adenoma from FNH, which classically shows a central scar and does not drop out. HCC may contain lipid but typically arises in a cirrhotic liver. Hemangioma does not contain intracellular fat and shows peripheral nodular enhancement.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.