Hepatic angiomyolipoma with minimal fat, mimicking hepatocellular carcinoma

Retrospective analysis of hepatic perivascular epithelioid cell tumour (PEComa) in a single centre for clinical diagnosis and treatment clinical diagnosis and treatment of hepatic PEComa

Our primary objective was to investigate the clinical features, diagnosis, treatment and prognosis of hepatic perivascular epithelioid cell tumour (PEComa).Thirty-five cases of pathologically proven hepatic PEComa that were treated in the Department of Hepatobiliary Centre of the First Affiliated Hospital of Nanjing Medical University from January 2008 to February 2019 were retrospectively analysed, and the literature was also reviewed.Twenty-nine females and 6 males were included in this study. The mean age of these patients was 48.0 years (range, 21-75 years). Thirteen patients complained of upper abdominal pain or discomfort, while others were accidentally discovered by imaging examination. Hepatic PEComas tended to occur in the right lobe of the liver (20 cases in the right lobe, 13 in the left lobe and 2 in the caudate lobe). Two cases were characterized by multiple tumours, and the remaining cases were single lesions (range, 1.2-12 cm). Only 8 cases were correctly diagnosed by the preoperative imaging examination, and the correct diagnosis rate was only 22.9%. The postoperative immunohistochemistry analysis showed that hepatic PEComas are positive for human melanoma black 45, Melan-A and smooth muscle actin, with the exception of 1 case that was negative for Melan-A. All patients undergoing an operation accepted regular follow-up, and the average time was 66.5 months (range, 3-132 months). Two patients who experienced tumour recurrence and 1 patient who died of cardiovascular disease, but the remaining patients showed no evidence of tumour recurrence or metastasis during the follow-up period.Hepatic PEComas are a rare type of tumours that mainly occur in young and middle-aged women. The lack of clinical manifestations and imaging findings increases the difficulty of determining a preoperative diagnosis, which mainly depends on the results of pathological examinations. Surgery is currently the only effective treatment, and long-term clinical follow-up is necessary due to the aggressive behaviour and relapse of hepatic PEComa in some patients.

Puzzling hepatic tumor: Epithelioid angiomyolipoma

Hepatic epithelioid angiomyolipomas are uncommon mesenchymal neoplasms. They are difficult to diagnose by imaging, especially when the fatty component is scant or absent. The gold standard for the diagnosis is histologic examination coupled with an immunohistochemical study. Positive HMB45 immunostaining of the myoid cells is a major diagnostic feature.

An MRI Image Analysis of Primary Cardiac Neoplasms

Objective

This study aimed to examine the magnetic resonance imaging (MRI) characteristics of primary cardiac neoplastic lesions.

Methods

A retrospective investigation was conducted on 24 cases of primary cardiac neoplastic lesions as confirmed by surgery and pathology results. All the cases in this study received MRI multi-sequence and multi-dimension scanning, including the cardiac long-axis and short-axis cine sequences, parameter sequences of the cardiac long axis and short axis (T1WI, T2WI), first-pass perfusion sequence, and delayed enhancement sequence of the cardiac long axis and short axis. The age and gender of the patients and the location, size, signal characteristics, and relationship with the neighboring tissues of all the lesions were examined.

Results

Twenty-four cases of primary neoplastic lesions were examined in this study, the onset age was 11–72 years old, the median age was 53 years old, and the mean age was 46 years old. Among these cases, there were 8 cases including males and 16 cases including females, 19 cases were benign lesions; including 11 cases of myxoma, 4 cases of hemangioma, 1 case of paraganglioma, 1 case of PEcoma, 1 case of hamartoma, and 1 case of lipoma. The malignant lesions included 3 sarcomas and 2 lymphomas in 5 patients.

Conclusion

MRI imaging provides a great value in the preoperative classification of primary cardiac neoplastic lesions.

Benign focal liver lesions masquerading as primary liver cancers on MRI

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common primary liver malignancies. HCC and ICC have characteristic imaging findings, but a number of benign entities can appear similar and can cause diagnostic dilemma. Ideally, accurate and timely diagnosis of these conditions can help the patient to avoid a needle biopsy or even unnecessary treatment. In this article, we present various benign liver lesions that display imaging characteristics that are similar to HCC and ICC on magnetic resonance imaging (MRI) and discuss salient features that may assist in accurate diagnosis.

FDG-PET/CT imaging findings of hepatic tumors and tumor-like lesions based on molecular background

The usefulness of whole-body 18-fluoro-2-deoxyglucose (FDG)-fluorodeoxyglucose positron emission (PET)/computed tomography (CT) is established for assessment of disease staging, detection of early disease recurrence, therapeutic evaluation, and predicting prognosis in various malignancies; and for evaluating the spread of inflammation. However, the role of FDG-PET/CT for the liver is limited because CT and magnetic resonance imaging (MRI) can provide an accurate diagnosis of most tumors. In addition, in other potentially useful roles there are several pitfalls in the interpretation of FDG uptake in PET/CT imaging. Accurate evaluation demands knowledge of the FDG uptake of each lesion, including potential negative and positive uptakes, and requires an understanding of the underlying background of the molecular mechanisms. The degree of FDG uptake is dependent on cellular metabolic rate and the expression of glucose transporter, hexokinase, and glucose-6-phosphatase, which in turn are closely affected by biological characteristics such as pathological category (e.g., adenocarcinoma, squamous cell carcinoma, small cell cancer, transitional cell cancer, neuroendocrine tumor, sarcoma, lymphoma), tumor differentiation, histological behavior (e.g., solid, cystic, mucinous), and intratumoral alterations (e.g., necrosis, degeneration, hemorrhage). Correlation with the CT and MRI findings, which also precisely depict the pathological findings, is important to avoid misdiagnosis.

Challenging liver lesions in noncirrhotic patients: Report of three cases

We describe three cases of liver lesions, characterized by a discrepancy between presurgical imaging and histological features, in which the final histological diagnosis was quite different from what the surgeons expected. We present (1) a case of primary liver angiomyolipoma associated with focal nodular hyperplasia, (2) a case of perivascular epithelioid cell tumor, and (3) a case of liver splenosis associated with focal nodular hyperplasia. In all cases, a presurgical diagnosis of hepatocellular adenoma was made. Due to nonspecific clinical and radiological features, these rare liver lesions are often presurgically misdiagnosed, especially in young noncirrhotic patients. The association among different lesions represents one additional diagnostic challenge.

Imaging findings of mimickers of hepatocellular carcinoma

Radiological imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. While imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The most common mimicker of HCC in cirrhotic liver is nontumorous arterioportal shunts that are seen as focal hypervascular liver lesions on dynamic contrast-enhanced cross-sectional imaging. Rapidly enhancing hemangiomas can be easily misdiagnosed as HCC especially on MR imaging with liver-specific contrast agent. Focal inflammatory liver lesions mimic HCC by demonstrating arterial-phase hypervascularity and subsequent washout on dynamic contrast-enhanced imaging. It is important to recognize the suggestive imaging findings for intrahepatic cholangiocarcinoma (CC) as the management of CC is largely different from that of HCC. There are other benign mimickers of HCC such as angiomyolipomas and focal nodular hyperplasia-like nodules. Recognition of their typical imaging findings can reduce false-positive HCC diagnosis.

MR characterization of focal liver lesions: pearls and pitfalls

Magnetic resonance (MR) can characterize specific tissue subtypes, thus facilitating focal liver lesion diagnosis. Focal liver lesions that are isointense to hyperintense to liver on T1-weighted images are usually hepatocellular in origin. Chemical shift imaging can narrow the differential diagnosis by detecting the presence of lipid or iron. T2 and heavily T2-weigthed fast spin echo imaging can differentiate solid from nonsolid focal liver lesions. The authors illustrate these MR imaging pearls and the uncommon exceptions (pitfalls). The authors hope that you will find this less traditional contribution to the Magnetic Resonance Clinics of North America helpful in clinical practice.

Hepatic angiomyolipoma mimicking hepatocellular carcinoma: magnetic resonance imaging and clinical pathological characteristics in 9 cases

Hepatic angiomyolipoma (HAML) is a rare mesenchymal tumor of the liver with marked histological diversity. The present study was to review the magnetic resonance imaging (MRI) and clinical pathological features of HAML resembling hepatocellular carcinoma (HCC). Nine patients who underwent surgical resection and had pathological diagnosis of HAML were retrospectively analyzed. All of 9 patients (5 males and 4 females) had a solitary hepatic mass with a median size of 4 cm (from 1.4 cm to 15.3 cm). Seven cases were identified as incidental liver tumors during health screening and 2 patients were diagnosed for hepatic mass when visited hospitals with unspecific abdominal discomfort. Before resection, 6 cases were diagnosed as HCC on MRI. MRI on chemical shift imagings showed a large amount of lipids in 5 cases. The enhancement pattern of MRI was classified into 2 types: in 2 cases, lesions with small or no vessels that demonstrated prolonged enhancement (1 mixed subtype and 1 myomatous subtype) and in 7 cases, lesions with abundant central vessels that show rapid washout (3 mixed subtypes and 4 myomatous subtypes) in the portal venous/delayed phase. All patients underwent resection of hepatic tumor and no recurrence was observed during follow-up (range: 2-24 months) of median 10 months. By immunohistochemistry, the tumor cells demonstrated positive immunostaining for human melanoma black-45, smooth muscle actin, and CD34. In conclusion, all of 9 patients with HAML presented with none or nonspecific clinical manifestations. The diagnosis of HAML relies on disease and immunohistochemistry, but not MRI due to its resemblance to HCC.

A case of multiple hepatic angiomyolipomas with high (18) F-fluorodeoxyglucose uptake

Background

Hepatic angiomyolipoma is a rare benign mesenchymal tumor. We report an unusual case of a patient with multiple hepatic angiomyolipomas exhibiting high ¹⁸ F-fluorodeoxyglucose (FDG) uptake.

Case presentation

A 29-year-old man with a medical history of tuberous sclerosis was admitted to our hospital for fever, vomiting, and weight loss. Abdominal dynamic computed tomography revealed faint hypervascular hepatic tumors in segments 5 (67 mm) and 6 (10 mm), with rapid washout and clear borders; however, the tumors exhibited no definite fatty density. Abdominal magnetic resonance imaging revealed that the hepatic lesions were slightly hypointense on T1-weighted imaging, slightly hyperintense on T2-weighted imaging, and hyperintense with no apparent fat component on diffusion-weighted imaging. FDG-positron emission tomography (PET) imaging revealed high maximum standardized uptake values (SUVmax) of 6.27 (Segment 5) and 3.22 (Segment 6) in the hepatic tumors. A right hepatic lobectomy was performed, and part of the middle hepatic vein was also excised. Histological examination revealed that these tumors were characterized by the background infiltration of numerous inflammatory cells, including spindle-shaped cells, and a resemblance to an inflammatory pseudotumor. Immunohistochemical evaluation revealed that the tumor stained positively for human melanoma black-45. The tumor was therefore considered an inflammatory pseudotumor-like angiomyolipoma. Although several case reports of hepatic angiomyolipoma have been described or reviewed in the literature, only 3 have exhibited high ¹⁸ F-FDG uptake on PET imaging with SUVmax ranging from 3.3–4.0. In this case, increased ¹⁸ F-FDG uptake is more likely to appear, particularly if the inflammation is predominant.

Conclusion

Although literature regarding the role of ¹⁸ F-FDG-PET in hepatic angiomyolipoma diagnosis is limited and the diagnostic value of ¹⁸ F-FDG-PET has not yet been clearly defined, the possibility that hepatic angiomyolipoma might exhibit high ¹⁸ F-FDG uptake should be considered.

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

OBJECTIVE

To display and analyse the imaging features of myomatous hepatic angiomyolipomas (MHAMLs).

METHODS

The imaging features (CT = 9; MRI = 10; ultrasound = 10; contrast-enhanced ultrasound = 4) of 14 patients with pathologically proven MHAMLs were reviewed retrospectively.

RESULTS

MHAMLs were surgically resected in the 14 patients (10 females and 4 males; age, 27-64 years; mean, 45 years), all of whom had negative hepatitis markers and were positive for the immunohistochemical stain homatropine methylbromide-45. The tumours were solitary and well defined, and ranged in size from 1.9 to 9.1 cm (mean, 5.7 cm). On dynamic contrast-enhanced CT, MRI and ultrasound scans, all tumours showed fast strong enhancement in the arterial phase and moderate washout in the portal venous and delayed phases, and the greater portions of the tumours were slightly lower than the surrounding hepatic parenchyma. In some cases, a small area of prolonged or increasing enhancement in the tumour was recognized in the delayed phase. Early draining vessels to the portal vein or hepatic vein could be seen in some cases. However, no capsular signs could be confidently identified in the delayed phase. Haemorrhagic cavities were recognized in two cases, and nodular low-intensity areas in the tumours on T2 weighted imaging that showed slow and faint enhancement on dynamic scans were seen in two cases. However, no necrosis was identified.

CONCLUSION

Dynamic enhanced imaging studies revealed some specific features of MHAMLs that distinguish them from other hypervascular hepatic tumours, especially when combined with clinical features. Familiarity with imaging and clinical features of MHAMLs could avoid unnecessary surgical resection of these generally benign tumours.

ADVANCES IN KNOWLEDGE

This article systematically describes the imaging features of MHAMLs.

Epithelioid angiomyolipoma of the liver: a clinicopathologic study of 5 cases

This study aimed to study the clinicopathologic characteristics of epithelioid angiomyolipoma, a variant of angiomyolipoma (AML) in the liver; and to discuss the diagnostic challenges. Five cases of primary liver epithelioid AML were retrieved from our archives from January 2003 to October 2012. The clinicopathologic features of each case were retrospectively reviewed. All 5 patients were female, with age ranging from 36 to 70 years (median, 41 years). The size of the tumor ranged from 1.2 to 25 cm. Histologically, the tumor comprised polygonal cells with granular eosinophilic cytoplasm and accompanied by immunohistochemical expression of HMB-45 ± Melan-A. Variations in growth pattern and cytology were observed. Estrogen receptor was negative in all 5 cases. None showed cytologic atypia, coagulative necrosis, increased mitotic count, or vascular invasion. Epithelioid AML is an uncommon primary liver tumor with a female predominance. The size of the tumor can be variable. This tumor might impose diagnostic difficulty both clinically and histologically. Immunohistochemical staining with melanocytic markers is a promising means to confirm the pathologic diagnosis. A careful assessment of aggressive histologic features is recommended to stratify the risk of aggressive behavior of this tumor.