Angiomyolipoma of the liver: a reappraisal of morphological features and delineation of new characteristic histological features from the clinicopathological findings of 55 tumours in 47 patients

Abstract

The majority of hepatic AMLs were myomatous in type, showing variable cellular morphology and growth patterns. Cellular atypia and invasive growth were frequent, indicating that hepatic AMLs often show malignancy-like histological features. Although the majority of cases behave as benign tumours, AML should be considered to have uncertain malignant potential, and careful follow-up of patients is recommended. Immunostaining for HMB-45 is specific for AML, and establishes the diagnosis. The occasional presence of abnormally large blood vessels around the tumour may give new insights into the evaluation of findings from imaging.

Recent Advances in the Imaging Diagnosis of Hepatocellular Carcinoma: Value of Gadoxetic Acid-Enhanced MRI

“…Hepatic AMLs are sometimes misdiagnosed as HCCs because arterial enhancement and the presence of fat components are common in both lesions [78]. In addition, there are also lipid-poor AMLs which have no detectable fat components on imaging studies making the differentiation from other hypervascular tumors difficult [77,79]. According to a recent study which compared Gd-EOB-MRI features of lipid-poor AMLs and HCCs, both lesions showed similar dynamic enhancement patterns with arterial enhancement followed by hypointensity on the PVP or TP [80] (fig.…”

“…Features suggestive of ICCs rather than HCCs include i) the absence of fat and a tumor capsule [74], ii) central hypointensity on T2-weighted images [74], iii) a lower proportion showing arterial enhancement [75], iv) a target appearance on HBP images [16], and v) a target appearance on DWI [76]. Hepatic angiomyolipoma (AML) is a rare benign mesenchymal tumor which is composed of variable proportions of thick-walled vessels, smooth muscle cells, and adipose tissue [77]. As a result of the various percentages of mixed histologic components, hepatic AMLs can manifest with diverse imaging features [78].…”

Myomatous hepatic angiomyolipoma: imaging findings in 14 cases with radiological–pathological correlation and review of the literature

“…Some studies have suggested that abnormally large dilated vessels should be considered a typical histological feature of MHAMLs, 16,18,24 and might be important in recognizing, understanding and interpreting the findings of various imaging modalities. In the present study, abnormally large dilated vessels were present in 10 of the 12 tumours that were .4.0 cm.…”

Gadoxetic Acid–enhanced Magnetic Resonance Imaging and Contrast-enhanced Ultrasonography in the Diagnosis of Hepatocellular Carcinoma

“…It has diverse imaging features and mimics HCC to show arterial enhancement, intralesional fat, and washout. 58,59 In addition, lipid-poor angiomyolipoma has no detectable fat component on imaging or chemical shift imaging. 58,60 On Gd-EOB-MRI, both entities show similar dynamic enhancement patterns, but angiomyolipoma tends to be more homogeneously hypointense and of lower signal intensity in HBP, as it does not contain hepatocytes, whereas HCC contains hepatocytes with various degrees of malignant change.…”