Hepatic angiomyolipoma: differential diagnosis from other liver tumors in a special reference to vascular imaging - importance of early drainage vein

A Case Report on a Giant Hepatic Inflammatory Adenoma in a Young Female That Presented as Spontaneous Intrahepatic Hematoma

Among the extensive variety of disorders that can cause acute abdominal pain are hepatocellular adenomas (HCAs), pathological entities that otherwise are asymptomatic. Here, we describe a 33-year-old female who presented in the emergency department with acute abdominal pain and a history of liver focal nodular hyperplasia (FNH) diagnosed 10 years ago. An abdominal magnetic resonance imaging (MRI) revealed that the cause of the pain was an intrahepatic hematoma. The mass was surgically removed, and the biopsy revealed inflammatory adenomas, a subtype of HCA. Hepatic adenoma diagnosis remains challenging by clinical and imaging techniques, and usually, a biopsy is the main diagnostic tool. HCA should be differentiated from hepatocellular carcinoma (HCC), FNH, hepatic angioleiomyoma, and hepatic hemangioma. In our case, HCA was misdiagnosed in the past as FNH. HCA rarely may present as acute right abdomen pain, and a potential catastrophic hemorrhage or rupture must be excluded.

A huge hepatic angiomyolipoma with growth during 5 years of follow-up

A 45-year-old woman was referred to our hospital with a huge liver tumor that had been diagnosed as a hepatic angiomyolipoma (HAML) 5 years previously. At the time of referral, it had enlarged from 12 to 20 cm within the previous 5 years and become symptomatic. Enhanced computed tomography revealed a very large, well-defined, low-density mass occupying the entire right lobe of the liver. The patient underwent right hemi-hepatectomy. The resected specimen weighed 1620 g and measured 20 × 14 × 8 cm. The pathological diagnosis was confirmed as benign HAML. The estimated growth rate of this tumor was 44% per year with a doubling time of 826 days. Although the majority of HAMLs are stable lesions, resection should perhaps be considered when the tumor is known to be growing and exceeds 6 cm in diameter, even if it has been diagnosed as benign.

Application of new ultrasound techniques for focal liver lesions

Ultrasonography (US) has the overwhelming advantages of not entailing radiation exposure and being a noninvasive, real-time, convenient, easy-to-perform, and relatively inexpensive imaging modality. It is used as the first-line imaging modality for screening, detection, and diagnosis of focal liver lesions (FLLs) [small hepatocellular carcinomas (HCCs), in particular]. However, with the increasing demand for accurate and early diagnosis of small HCCs, newer radiologic methods need to be explored to overcome certain limitations of US. For example, the imaging is easily negatively affected by the presence of gas, rib cage, and subcutaneous fat, and is insensitive for capturing the subtle but vital information on the blood flow. It was in response to this need that new promising technologies such as contrast-enhanced ultrasound and fusion imaging were introduced for the detection of liver lesions. This paper presents an overview of the epidemiology and mechanisms of the development of HCCs, with an emphasis on the application of US in the diagnosis and treatment of FLLs. The aim of this article is to provide the state-of-the-art developments in the imaging diagnosis of FLLs and evaluation of ablation treatment of early HCCs. By keeping abreast of these recent advances, we hope that doctors and researchers working in the field of diagnosis/treatment of liver diseases will be able to discriminate benign FLLs such as regenerative nodules and focal nodular hyperplasia from HCCs, so as to avoid unnecessary repeated tumor biopsies and overtreatment. In particular, we expect that small HCCs or precancerous nodules (such as dysplastic nodules) can be accurately diagnosed and appropriately treated even at an early stage.

Radiological aspects of giant hepatocellular adenoma of the left liver: A case report

BACKGROUND

Hepatocellular adenoma (HCA) is very rare and has a high misdiagnosis rate through clinical and imaging examinations. We report a case of giant HCA of the left liver in a young woman that was diagnosed by medical imaging and pathology.

CASE SUMMARY

A 21-year-old woman was admitted to our department for a giant hepatic tumor measuring 22 cm × 20 cm × 10 cm that completely replaced the left hepatic lobe. Her laboratory data only suggested mildly elevated liver function parameters and C-reactive protein levels. A computed tomography (CT) scan showed mixed density in the tumor. Magnetic resonance imaging (MRI) of the tumor revealed a heterogeneous hypointensity on T1-weighed MR images and heterogeneous hyperintensity on T2-weighed MR images. On dynamic contrast CT and MRI scans, the tumor presented marked enhancement and the subcapsular feeding arteries were clearly visible in the arterial phase, with persistent enhancement in the portal and delayed phases. Moreover, the tumor capsule was especially prominent on T1-weighted MR images and showed marked enhancement in the delayed phase. Based on these imaging manifestations, the tumor was initially considered to be an HCA. Subsequently, the tumor was completely resected and pathologically diagnosed as an HCA.

CONCLUSION

HCA is an extremely rare hepatic tumor. Preoperative misdiagnoses were common not only due to the absence of special clinical manifestations and laboratory examination findings, but also due to the clinicians’ lack of practical diagnostic experience and vigilance in identifying HCA on medical images. Our case highlights the importance of the combination of contrast-enhanced CT and MRI in the preoperative diagnosis of HCA.

Hepatic angiomyolipoma with early drainage veins into the hepatic and portal vein

Hepatic angiomyolipoma (AML) is a rare stromal tumor composed of variable admixtures of thick-walled vessels, smooth muscles and adipose tissue. One of the specific radiological findings of hepatic AML is an early drainage vein noted via enhanced computed tomography (CT). We report a case of hepatic AML showing early drainage veins into both the hepatic and portal vein. The case involved a 46-year-old woman who was referred to our hospital because of a giant hepatic tumor. CT revealed well-enhanced 14 cm and 1 cm tumors in the left and right lobes, respectively. Magnetic resonance imaging demonstrated the existence of adipose tissues in the larger tumor. Hepatic arteriography revealed early drainage veins draining into both the hepatic and portal vein. Based on a diagnosis of hepatic AML, left hepatectomy and partial hepatectomy were performed. Pathology revealed both tumors as hepatic AML based on human melanoma black-45 immuno-positivity. Hepatic AML with early drainage veins into both the hepatic and portal vein is rare. The dilated and retrogressive vein drains the abundant arterial blood flow of the tumor. The finding of early drainage veins into not only the hepatic vein but also the portal vein should be helpful for diagnosing hepatic AMLs.

Comparison of MRI Features of Epithelioid Hepatic Angiomyolipoma and Hepatocellular Carcinoma: Imaging Data From Two Centers

Introduction: Epithelioid hepatic angiomyolipoma (Epi-HAML) can easily be misdiagnosed as a malignant tumor such as hepatocellular carcinoma (HCC) because of the low-fat content on imaging. We analyzed and compared the magnetic resonance imaging (MRI) features of Epi-HAML and HCC, which would aid in disease diagnosis.

Methods: We included 30 pathologically confirmed patients with Epi-HAML and 80 with HCC, who underwent both MRI unenhanced scan and three-phase contrast-enhanced MRI scan. The clinical and MRI features of the two groups were summarized and analyzed.

Results: Epi-HAML showed significant differences compared to HCC group in terms of clinical features such as sex preference, age, concomitant diseases (hepatitis B and cirrhosis), and elevated plasma alpha-fetoprotein (AFP) (P < 0.001). In addition, there were statistically significant differences between both tumor types with regard to conventional MRI findings such as a solitary tumor (100 vs. 83.8%, P = 0.018), well-defined (93.3 vs. 71.3%, P = 0.027), mild hyperintensity (40.0 vs. 3.7%, P < 0.001) on DWI with high b-value, fat within the tumor (43.3 vs. 8.8%, P < 0.001), and rare necrosis (3.3 vs. 26.3%, P = 0.016). Besides, Epi-HAML displayed significant differences compared to HCC in terms of contrast-enhanced MRI characteristics such as draining hepatic vein (30.0 vs. 3.8%, P < 0.001), portal vein tumor thrombus (0 vs. 13.8%, P = 0.033), hypointensity at delayed phase (70.0 vs. 95%, P = 0.001), intra-tumor vessel at delayed phase (36.7 vs. 10.0%, P = 0.003), pseudocapsule (20.0 vs. 78.8%, P < 0.001), and prolonged enhancement (56.7 vs. 1.2%, P < 0.001).

Conclusion: Epi-HAML frequently occurs in middle-aged women and usually lacks characteristic clinical symptoms. Typically, Epi-HAML presents as an isolated and well-defined tumor with rich vasculature. Specific MRI features such as intra-tumor fat, intra-tumor vessel, draining hepatic vein, prolonged enhancement, and lack of capsule may contribute to a more confident diagnosis of Epi-HAML.