A 32-year-old woman comes to the office due to a 2-month history of dull pain in the right upper quadrant. The pain is worse with deep inspiration. The patient has no fever or weight loss. She drinks alcohol socially but does not use tobacco or recreational drugs. The patient has no significant family history of cancer. Temperature is 37.1 C (98.8 F), blood pressure is 130/78 mm Hg, pulse is 82/min, and respirations are 16/min. BMI is 36 kg/m2. There is no jaundice. On examination, mild hepatomegaly is noted; no ascites is present. Abdominal ultrasonography reveals a solitary 4.5-cm mass in the right lobe of the liver. The patient undergoes surgical resection. On gross examination, the mass is soft and smooth with a tan appearance. On cut surface, areas of hemorrhage and necrosis are noted. Microscopic examination shows cells that are larger than normal hepatocytes and have small, regular nuclei without mitoses. There are scattered prominent arteries; no portal tracts or interlobular bile ducts are present. Which of the following is the most likely diagnosis?
Hepatocellular adenoma | |
Epidemiology |
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Clinical |
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Pathology |
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OCPs = oral contraceptive pills. | |
This patient's pathologic features are consistent with hepatocellular adenoma (HCA), an uncommon benign liver tumor found predominantly in young women. It is associated with estrogen exposure (eg, oral contraceptive pills), anabolic steroid use, and obesity. Pathogenesis is thought to be hormonally mediated but is not fully understood.
Macroscopically, HCA is typically a well-circumscribed, solid, solitary, unencapsulated mass arising in the right lobe. The cut surface is often soft and tan with areas of hemorrhage and necrosis. Histologically, HCA is composed of sheets or plates of benign hepatocytes. Cells may be larger than normal hepatocytes but have small, uniform nuclei (ie, no cytologic atypia) and rare mitoses. Normal hepatic architecture is absent; instead, there are prominent arteries without normal portal tracts or interlobular bile ducts. The uninvolved liver is usually noncirrhotic.
Patients may be asymptomatic (ie, diagnosed incidentally by imaging) or have epigastric or right upper quadrant pain (due to hepatomegaly or intralesional bleeding or necrosis). Because HCA is an unencapsulated and vascular lesion, there is risk for rupture with life-threatening intraabdominal bleeding (eg, severe abdominal pain, hypotension). For this reason, large or symptomatic HCAs are usually surgically resected.
(Choice A) Focal nodular hyperplasia, a nonneoplastic liver lesion, occurs primarily in young women. Although typically a well-circumscribed, solitary mass, it characteristically has a central stellate scar.
(Choice C) Hepatocellular carcinoma (HCC) typically arises in older patients with underlying liver disease and cirrhosis. The macroscopic appearance can vary, but histopathology often shows atypical hepatocytes with increased mitoses. Although malignant transformation of HCA occasionally occurs, this patient's histopathology is not suggestive of HCC.
(Choice D) Pyogenic hepatic abscess commonly results from biliary tract infection or portal vein pyemia (eg, bowel leakage). Although it causes abdominal pain, patients are typically febrile. Pathologic examination often shows a soft, yellow-green, necrotic lesion composed of neutrophils and debris.
(Choice E) The liver is a common site of metastasis in patients with a history of malignancy (eg, colorectal). Histopathology of metastases may resemble that of the primary tumor (eg, atypical epithelial cells forming infiltrative glands); mitoses are common.
Educational objective:
Hepatocellular adenomas are benign liver tumors found predominantly in young women with a history of oral contraceptive use. They are typically solitary, unencapsulated masses composed of benign hepatocytes and prominent arteries without normal portal tracts. Patients may be asymptomatic, have abdominal pain, or have intraabdominal bleeding due to tumor rupture.