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A 35-year-old woman is evaluated for a 6-month history of right upper quadrant abdominal pain that has slowly increased in intensity and is worse on deep inspiration. The patient is otherwise well, and her only medication is an oral contraceptive pill that she has taken for 15 years. She drinks alcohol socially but has no history of heavy alcohol use, injection drug use, or blood transfusion.
On physical examination, vital signs are normal; BMI is 26. There is slight hepatomegaly with mild discomfort on deep palpation in the right upper quadrant and mid-epigastrium. There is no jaundice or ascites. The lungs are clear. Complete blood count and serum biochemistry studies, including aminotransferases, bilirubin, and α-fetoprotein, are normal. Ultrasonography shows a solitary hyperechoic 9-cm lesion in the right lobe of the liver. CT scan shows a well-demarcated lesion with peripheral enhancement after injection of intravenous contrast; there is no central scar. Liver biopsy specimen reveals sheets of hepatocytes, with no bile ducts or Kupffer cells.
Which of the following is the most likely diagnosis?
A) Focal nodular hyperplasia
B) Hepatic adenoma
C) Hepatocellular carcinoma
D) Simple hepatic cyst
MKSAP Answer and Critique
The correct answer is B) Hepatic adenoma. This item is available to MKSAP 15 subscribers as item 102 in the Gastroenterology and Hepatology section. More information about MKSAP 15 is available online.
This patient likely has hepatic adenoma, which is associated with oral contraceptive use and occurs most commonly in women between the ages of 20 and 45 years. These lesions are usually solitary and occur most frequently in the right lobe. Diagnosis of hepatic adenoma depends on a lesion occurring in the proper clinical setting, with imaging showing a hyperechoic lesion on ultrasonography and peripheral arterial enhancement on a contrast-enhanced CT scan. MRI shows hyperintensity on both T1- and T2-weighted images. Surgical resection should be considered for patients with symptomatic hepatic adenomas.
The absence of a central scar makes focal nodular hyperplasia less likely than adenoma, although only one third of focal nodular hyperplastic lesions have a central scar. The lack of bile ducts and Kupffer cells on the biopsy specimen would effectively exclude focal nodular hyperplasia, in which such findings are prominent. The solid nature of the lesion on imaging excludes the diagnosis of simple hepatic cyst. The MRI in hepatocellular carcinoma usually shows high intensity on T2-weighted imaging and low intensity on T1-weighted images. Biopsy is generally not needed to make the diagnosis. In addition, the normal serum α-fetoprotein concentration, absence of cirrhosis, and biopsy findings make hepatocellular carcinoma highly unlikely.
Key Point
- Hepatic adenomas show a hyperechoic lesion on ultrasonography and peripheral arterial enhancement on a contrast-enhanced CT scan.
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