Hepatic Adenomas: Imaging and Pathologic Findings

Abstract

Hepatocellular adenoma is a rare benign lesion that is most often seen in young women with a history of oral contraceptive use. It is typically solitary, although multiple lesions have been reported, particularly in patients with glycogen storage disease and liver adenomatosis. Because of the risk of hemorrhage and malignant transformation, hepatocellular adenomas must be identified and treated promptly. At pathologic analysis, hepatocellular adenoma is usually a well-circumscribed, nonlobulated lesion, and at gross examination, resected adenomas frequently demonstrate areas of hemorrhage and infarction. Most adenomas are not specifically diagnosed at ultrasonography (US) and are usually further evaluated with computed tomography (CT) or other imaging modalities. Color Doppler US may help differentiate hepatocellular adenoma from focal nodular hyperplasia. Multiphasic helical CT allows more accurate detection and characterization of focal hepatic lesions. Hepatocellular adenomas are typically bright on T1-weighted magnetic resonance images and predominantly hyperintense relative to liver on T2-weighted images. The prognosis of hepatic adenoma is not well established. Criteria that guide treatment include the number and size of the lesions, the presence of symptoms, and the surgical risk incurred by the patient. Understanding the imaging appearance of hepatocellular adenoma can help avoid misdiagnosis and facilitate prompt, effective treatment.

Hepatic adenomas: Presumed innocent until proven to be beta-catenin mutated

“…Macroscopically, HA presents as a solitary, yellowish mass due to lipid accumulation and gives a pseudo-encapsulated appearance because of the compression of adjacent hepatic tissue. 6 Some of the histological features include areas of fatty deposits and hemorrhage, cord-or plate-like arrangements of larger hepatocytes containing excessive glycogen and fat, sinusoidal dilatation (the result of the effects of arterial pressure as these tumors lack a portal venous supply), absent bile ductules, and presence of few and non-functioning Kupffer cells. 2,6 The extensive hypervascularity and a lack of a true capsule makes this tumor prone to hemorrhage.…”

“…2,6 The tumors can regress in size following discontinuation of inciting factors such as oral contraceptives; at other times they continue to exhibit a stable or progressive disease. However, the risk of associated hemorrhage and neoplastic transformation is always present.…”

“…While this has been tried by screening for elevated ␣-fetoprotein levels as well as radiologically by serial examinations to identify first signs of such transformation, the success has been limited. 6 The true prognostic indicators would come from understanding the molecular basis of this disease, which is what Zucman-Rossi et al attempted in their report in the current issue of HEPATOLOGY. 11 In the study, the authors examined 96 liver tumors with a diagnosis of hepatic adenoma.…”

Liver cell adenoma showing sequential alteration of radiological findings suggestive of well-differentiated hepatocellular carcinoma

“…Due to the progress of diagnostic imaging techniques, the typical findings of LCA have been identified [4,11] . A typical LCA shows low density or isodensity on plain CT, presents a homogenous contrasting effect on arterial phase and does not show an apparent wash out on delayed phase.…”

“…However, precise pathological examination is not possible by these treatments. Since a definitive diagnosis of LCA by diagnostic imaging alone or by needle biopsy is difficult [11] , tumor resection is often the most suitable approach. Our case was found by chance during treatment of the endometriosis complicated with bacterial infection.…”