Diagnostic difficulties and treatment strategy of hepatic angiomyolipoma

Risk prediction criteria for the primary hepatic perivascular epithelioid cell tumour family, including angiomyolipoma: analysis of 132 cases with a literature review

AIMS

The hepatic perivascular epithelioid cell tumour (PEComa), including angiomyolipoma, exhibits diverse morphology and clinical behaviour; however, its prognostic features remain undefined. This study aimed to investigate its histological features and prognostic factors.

METHODS AND RESULTS

In total, 132 patients were included. Clinical data and histopathological slides were assessed along with the p53 and Ki-67 immunohistochemistry. Targeted next-generation sequencing was performed in three cases. Based on the histologic subtypes, 7 (10%), 36 (51%), 13 (18%), and 15 (21%) patients were classified as inflammatory angiomyolipoma, conventional angiomyolipoma, epithelioid angiomyolipoma, and PEComa not otherwise specified (NOS), respectively, among 71 patients who underwent surgical resection. We proposed the risk prediction criteria after defining primary tumour size ≥7 cm, infiltrative border, mitotic rate >1/10 mm2, necrosis, vascular invasion, and PEComa NOS as worrisome features, as follows: high-risk: ≥3 worrisome features; intermediate-risk: 1-2 features; low-risk: none of the features. Applying these criteria, 4 (6%), 31 (44%), and 36 (51%) patients were classified into high-, intermediate-, and low-risk groups, respectively. One patient each in the high-risk (25%) and intermediate-risk (3%) groups developed peritoneal metastases and intrahepatic recurrence, respectively, whereas none in the low-risk group showed disease progression. A literature review of clinically malignant hepatic PEComa family tumours was conducted, and upon application of our criteria, 62% (16/26) of the patients were classified as high-risk and 35% (9/26) as intermediate- or high-risk.

CONCLUSION

Our risk prediction criteria can effectively predict the clinical outcomes in primary hepatic PEComa.

Ceus features of liver pecoma: a case report and literature review

Perivascular epithelioid cell neoplasms (PEComas) and epithelioid angiomyolipomas (EAMLs) are two different denominations for the same "mesenchymal tumor composed of histologically and immunohistochemically distinctive perivascular epithelioid cells". Hepatic PEComa/EAML is a very rare neoplasm, and only 29 case reports of hepatic PEComa and 25 of hepatic EAML have been reported in the current literature. A clear female predominance with a mean age at diagnosis of 42.5 years old can be observed by literature review. Ultrasound (US) examination was the first-line diagnostic technique in most of the cases of hepatic PEComa, but it was documented in very few cases of hepatic EAML. A great variability in the ultrasonographic B-mode, color Doppler and contrast-enhanced ultrasonography (CEUS) features of hepatic PEComa/EAML emerges. Computed tomography and magnetic resonance were the most common used techniques to confirm the nature of the hepatic lesion, even if the anatomo-pathological examination was the only technique to display a certainty diagnosis and to differentiate hepatic PEComa/EAML from benign and malignant hepatic lesions. The great majority of hepatic PEComas/EAMLs are surgically treated without any adjuvant therapy.

Hepatic perivascular epithelioid cell tumors: The importance of preoperative diagnosis

Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors (PEComas) because PEComas are mainly benign tumors and may not require surgical intervention. By analyzing the causes, properties and clinical manifestations of PEComas, we summarize the challenges and solutions in the diagnosis of PEComas.

Hepatic angiomyolipoma masquerading as abdominal pain: A case report

INTRODUCTION AND IMPORTANCE

Hepatic angiomyolipoma (HAML) is a rare liver tumor composed of blood vessels, smooth muscle, and fat cells. HAML occurs across a wide age range, with symptoms including abdominal discomfort, bloating, and weight loss. Diagnosis is challenging due to varied imaging appearances, but histopathological examination supplemented by immunohistochemical analysis, particularly using HMB-45, is definitive.

CASE PRESENTATION

A 33-year-old man presented with a two-year history of right upper quadrant abdominal pain, occasionally relieved with analgesics but worsening over the past month and a half. Examinations revealed a soft, non-distended abdomen with a palpable liver. Laboratory tests, including viral markers and tumor markers were normal. Contrast-enhanced CT revealed a well-defined oval mass in liver segment III with heterogeneous enhancement leading to provisional diagnosis of HAML. The patient underwent a successful en bloc excision with no intraoperative or postoperative complications.

CLINICAL DISCUSSION

Surgical resection is recommended for symptomatic cases or inconclusive biopsies, with stringent follow-up necessary due to the potential for recurrence and association with other malignancies.

CONCLUSION

HAML may present with prolonged nonspecific abdominal symptoms. CT imaging aids in diagnosing cases with abundant fatty tissue. En bloc tumor excision proves safe and effective in treating symptomatic presentations.

Clinical characteristics and outcomes of patients with hepatic angiomyolipoma: A literature review

First reported in 1976, hepatic angiomyolipoma (HAML) is a rare mesenchymal liver tumor occurring mostly in middle-aged women. Diagnosis of the liver mass is often incidental on abdominal imaging due to the frequent absence of specific symptoms. Nearly 10% of HAMLs are associated with tuberous sclerosis complex. HAML contains variable proportions of blood vessels, smooth muscle cells and adipose tissue, which renders radiological diagnosis hazardous. Cells express positivity for HMB-45 and actin, thus these tumors are integrated into the group of perivascular epithelioid cell tumors. Typically, a HAML appears on magnetic resonance imaging (or computed tomography scan) as a hypervascular solid tumor with fatty areas and with washout, and can easily be misdiagnosed as other liver tumors, particularly hepatocellular carcinoma. The therapeutic strategy is not clearly defined, but surgical resection is indicated for symptomatic patients, for tumors showing an aggressive pattern (i.e., changes in size on imaging or high proliferation activity and atypical epithelioid pattern on liver biopsy), for large (> 5 cm) biopsy-proven HAML, and if doubts remain on imaging or histology. Conservative management may be justified in other conditions, since most cases follow a benign clinical course. In summary, the correct diagnosis of HAML is challenging on imaging and relies mainly on pathological findings.

Imaging hepatic angiomyolipomas: key features and avoiding errors

Hepatic angiomyolipomas (HAMLs) are rare mesenchymal neoplasms, which have highly variable imaging appearances, often leading to misdiagnosis. They belong to the family of perivascular epithelioid cell neoplasms (PEComas). HAMLs have a wide spectrum of imaging appearances due to variable amounts of smooth muscle cells, adipose tissue, and blood vessels in their makeup. Although typically sporadic, they are also associated with tuberous sclerosis. Sporadic lesions tend to be solitary whilst patients with tuberous sclerosis often have multiple HAMLs invariably accompanied by renal AMLs. Having been originally considered benign hamartomas, increasing reports of complications, including malignant behaviour, has also resulted in uncertainty in regard to their optimal management. Typically described imaging characteristics are of a hypervascular fat-containing lesion with prominent intratumoural vessels and an early draining vein; however HAMLs commonly demonstrate a paucity of fat or wash-out on contrast-enhanced imaging, and not all HAML lesions are hypervascular. HAMLs can therefore easily be misdiagnosed as other hepatic lesions, in particular hepatocellular carcinoma. This review describes the imaging characteristics of HAMLs, illustrating the wide variety of potential appearances across ultrasound, contrast-enhanced ultrasound, computed tomography, and magnetic resonance imaging, and highlights the challenges and potential errors that can be made. This review will aid radiologists in avoiding potentially major pitfalls when faced with this rare but important liver pathology.

Malignant potential of epithelioid angiomyolipomas of the liver: A case report and comprehensive review of the literature

Hepatic epithelioid angiomyolipoma (HEAML) is a rare mesenchymal tumor that has been reported to have malignant potential. We herein describe a rare case of atypical HEAML. A 43-year-old Caucasian male patient visited his general practitioner due to a productive cough persisting for >2 months. During evaluation with several imaging tests, a chest computed tomography (CT) incidentally revealed a well-demarcated lesion in the caudate lobe of the liver, sized 7 cm. An abdominal magnetic resonance imaging examination confirmed the findings of the CT. The possibility of hepatocellular carcinoma at that time could not be excluded. Due to inconclusive cross-sectional imaging, the patient underwent left hepatectomy with additional resection of segment I. The patient's postoperative course was uneventful. A diagnosis of 'atypical' HEAML was established in the present case. The majority of HEAMLs are considered to be benign, although there are several reported cases exhibiting malignant behavior, such as tumor growth, presence of atypical cells, recurrence after surgical resection, metastasis and invasive growth into the liver parenchyma and alongside the vessels. From 2000 onwards, 19 cases of malignant hepatic AML have been reported. Malignant transformation is considered to occur mostly in the epithelioid subtype. To that end, when epithelioid or atypical characteristics are identified on preoperative biopsy, resection is indicated due to the high probability of malignancy.

Differentiation of lipid poor angiomyolipoma from hepatocellular carcinoma on gadoxetic acid-enhanced liver MR imaging

PURPOSE

To investigate magnetic resonance (MR) findings of angiomyolipoma (AML) on gadoxetic acid-enhanced MR imaging, and to identify features that differentiate AML from hepatocellular carcinoma (HCC) in patients with a low risk of HCC development.

METHODS

This retrospective study was institutional review board approved, and the requirement for informed consent was waived. Twelve patients with hepatic AML who underwent gadoxetic acid-enhanced MRI with no risk factors for HCC development were recruited. Twenty-seven patients with HCC under the same inclusion criteria were recruited as control. Two radiologists analyzed the images in consensus for morphologic features, enhancement patterns, and hepatobiliary phase (HBP) findings. All results were analyzed using the Mann-Whitney test, two-tailed Fisher exact test, and chi-square test.

RESULTS

Patients with AML were younger than those with HCC (48.8 ± 15 years for AML vs. 62.7 ± 14.2 years for HCC, p = 0.008) with female predominance, while most HCC patients were male (75% (9/12) vs. 15% (4/27), p < 0.001). The most prevalent enhancement pattern was arterial enhancement followed by hypointensity at portal or transitional phases for both AMLs (58% (7/12)) and HCCs (74% (20/27)) (p = 0.455). However, during the HBP, AMLs frequently showed more homogeneous hypointensity than HCCs (83% (10/12) vs. 41% (11/27), p = 0.018). When compared with the signal intensity of the spleen, the mean relative signal intensity of the AML was 91.2 ± 15.4%, while in HCCs, it was 128.7 ± 40% (p < 0.001).

CONCLUSIONS

Although AMLs showed similar enhancement patterns to HCCs during the dynamic phases of gadoxetic acid-enhanced MRI, using characteristic MR features of AML during the HBP and demographic differences, one can better differentiate AML from HCC.

Hepatic angiomyolipoma with special attention to radiologic imaging

Background

Angiomyolipoma is a unique mesenchymal neoplasm composed of blood vessels as well as smooth muscle and adipose cells. The liver is a less common site of origin, and hepatic angiomyolipoma is often an incidental finding on diagnostic imaging or is identified on evaluation of nonspecific symptoms.

Case presentation

We experienced four patients who were diagnosed histologically with hepatic angiomyolipoma. The preoperative diagnoses were angiomyolipoma in two patients, hepatocellular carcinoma in one, and cavernous hemangioma in one. Three patients were treated with hepatectomy (one laparoscopic and two open approaches), and the diagnosis was completed by histological investigation of the resected specimen. The remaining one was diagnosed from tumor needle biopsy. Diffusion-weighted magnetic resonance imaging (MRI) with respiratory triggering using b values of 0 and 800 s/mm² was employed. An apparent diffusion coefficient map was generated from b values of 0 and 800 s/mm² for calculation of the apparent diffusion coefficient. The apparent diffusion coefficient values were calculated as 3.66, 1.21, 1.80, and 0.91 in patients 1 to 4, respectively. In MRI imaging, fat component was clearly demonstrated with chemical shift imaging in three patients. Early venous return was detected in three patients with computed tomography angiography.

Conclusion

Fat component and early venous return are important for a correct diagnosis of hepatic angiomyolipoma. Unfortunately, apparent diffusion coefficient values in hepatic angiomyolipoma were overlapping with those in other benign and malignant tumors.

Diagnosis and treatment of hepatic angioleiomyolipoma: A case report and literature review

AIM: To investigate the clinical features, imaging manifestations, pathological characteristics, differential diagnosis, treatment and prognosis of hepatic angiomyolipoma (HAML).

METHODS: A case of HAML diagnosed at our hospital is reported. A review of the literature was performed to retrospectively analyze 540 cases reported in China between 1987 and 2014.

RESULTS: HAML was more frequently found in females (2.7:1). Most of the patients (66.7%) presented no significant symptoms, and tumor marks were negative in all the patients. CT performed better for preoperative diagnosis than MRI (CT vs MRI: χ² = 11.321, P = 0.001) and ultrasound. Immunohistochemical analyses revealed that the positive expression rates of human melanoma black-45 antigen (HMB-45), smooth muscle actin (SMA), Vimentin, CD34 and CD117 in HAML were 97.8% (357/365), 93.7% (207/221), 62.5% (30/48), 40.5% (51/126) and 39.0% (48/123), respectively. The expression of HMB-45 was considered to have great significance in confirming the diagnosis. Of all the patients, 521 (96.3%) underwent surgical intervention, and recurrence or metastasis was found in only 3 patients during follow-up.

CONCLUSION: HAML lacks specific symptoms or signs, has diverse imaging manifestations, and can be easily misdiagnosed. Pathological and immunohistochemical analyses are essential for diagnosis, and surgical treatment has a good prognosis.

Is surgery necessary for patients with hepatic angiomyolipoma? Retrospective analysis from eight Chinese cases

BACKGROUND AND AIM

Hepatic angiomyolipoma (AML) is a rare, hepatic mesenchymal neoplasm. Its preoperative diagnosis is very difficult, and the treatment is still controversial. The aim is to summarize experience in diagnosis and management of hepatic AML from a cancer center.

METHODS

We retrospectively reviewed the clinical presentation, histopathological, features and treatment of the tumors encountered at our institute from January 2000 to December 2012.

RESULTS

The patients included six females and two males, with female preponderance. Six patients are asymptomatic. Laboratory tests lack specificity. Combining imaging modality, only one patient obtained the accurate diagnosis of hepatic AML and was confirmed by fine-needle aspiration biopsy combined with homatropine methylbromide-45 staining. All other patients received hepatic resection. There was no tumor recurrence or increase of tumor size within the follow-up period.

CONCLUSION

We suggest fine-needle aspiration combined with homatropine methylbromide-45 staining should be performed in all patients who are asymptomatic and without serological abnormalities. Surgical resection might be considered only if the malignant potential of the lesion cannot be ruled out or the tumor size is increasing during observation.