Management of hepatic angiomyolipoma: A systematic review

PEComa-its clinical features, histopathology, and current therapy

Perivascular epithelioid cell tumors (PEComas) are a rare family of mesenchymal tumors that includes angiomyolipoma, lymphangioleiomyomatosis, pulmonary clear cell "sugar" tumors, and PEComa-not otherwise specified. This study aimed to provide a comprehensive review of the clinical features, molecular biology, and current status of PEComa treatment. It reportedly occurs at several sites, including the uterus, kidney, liver, lung, abdominopelvic soft tissue, gastrointestinal organs, retroperitoneum, soft tissue, bone, and skin. More common in women, it occurs in young to middle-aged people. Although the disease generally follows a benign course, cases of malignant PEComa have been reported. Malignant PEComa is characterized by a large tumor size, a high mitotic rate, and the presence of necrosis and nuclear atypia. Immunohistochemically, PEComas typically express melanocytic markers such as human melanoma black 45 (HMB45) and melanoma antigen (melan-A) and muscle markers such as smooth muscle actin (α-SMA), desmin, and caldesmon. More recently, a subtype of PEComa harboring TFE3 gene rearrangement that is mutually exclusive with tuberous sclerosis complex (TSC) mutations has been identified. The identification of TFE3 gene rearrangement can help confirm the diagnosis. The distinctive features of these TFE3-rearranged PEComas include a young-age tendency, the absence of an association with tuberous sclerosis, predominant alveolar architecture and epithelioid cytology, minimal immunoreactivity for muscle markers, and strong (3+) TFE3 immunoreactivity. Surgery is the curative treatment of choice; however, there are reports of cases and randomized controlled trials showing the efficacy of mTOR inhibitors. To the best of our knowledge, there are no reports of radiation therapy's efficacy.

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.

Discontinuous peripheral enhancement of focal liver lesions on CT and MRI: outside the box of typical cavernous hemangioma

The discontinuous peripheral enhancement is a pattern of enhancement usually attributed to typical cavernous hemangioma, that is the most common benign solid lesion of the liver. The discontinuous peripheral enhancement, however, may be encountered in many other benign and malignant focal liver lesions as an atypical presentation or evolution, and hemangiomas with discontinuous peripheral hyperenhancement on hepatic arterial phase may not always have the typical post-contrast pattern on portal venous and delayed phases. Therefore, abdominal radiologists may be challenged in their practice by lesions with discontinuous peripheral enhancement. This pictorial essay aims to review the spectrum of benign and malignant focal liver lesions that may show discontinuous peripheral enhancement. A particular point of interest is the diagnostic tree pathway that may guide the radiologists in the differential diagnosis.

Unveiling the mystery of hepatic epithelioid angiomyolipoma: A unique case report with literature review

Hepatic epithelioid angiomyolipoma is a rare mesenchymal liver tumor within the perivascular epithelioid cell tumor family, known for its uncertain malignancy and potential for aggressive behavior. Clinical presentation, laboratory findings, and imaging results lack specificity, making pathological examination critical for definitive diagnosis. This case report presents a 61-year-old male patient with a single tumor in the right liver lobe, measuring approximately 101 mm × 99 mm. Initial imaging misdiagnosed the mass as hepatocellular carcinoma. Following multidisciplinary treatment discussions and subsequent tumor resection, histopathology and immunohistochemistry confirmed hepatic epithelioid angiomyolipoma. Accurate diagnosis of hepatic epithelioid angiomyolipoma is challenging, relying on histopathological examination and immunohistochemistry as diagnostic standards. Continuous monitoring of patients with hepatic epithelioid angiomyolipoma over an extended period is deemed essential. This report highlights the positive impact of multidisciplinary treatment in diagnosing and managing hepatic epithelioid angiomyolipoma.

Practical approach to diagnose and manage benign liver masses

Benign liver lesions are among the most commonly diagnosed abnormalities in liver imaging. They are often discovered incidentally during routine examinations or imaging conducted for unrelated reasons. These can be solid lesions, such as hemangiomas, focal nodular hyperplasia, hepatic adenomas, or cystic lesions. Recent advancements in MRI technology, particularly with hepatocyte-specific contrast agents, have enhanced the characterization of these lesions, reducing the reliance on invasive tissue sampling. Nevertheless, tissue sampling retains a crucial role in the evaluation of indeterminate lesions or those with malignant potential. While most benign liver lesions are asymptomatic, some can become symptomatic, causing discomfort, pain, or bleeding, particularly if the lesion is large. A deep understanding of the molecular underpinnings of the lesions is crucial for tailoring patient management strategies, particularly in distinguishing lesions that require surgical intervention from those that can be monitored. For instance, the molecular subclassification of hepatic adenomas has provided mechanistic insights and identified certain subtypes that are at higher risk of malignancy. Most benign liver lesions can be safely monitored; however, in patients with cirrhosis or a known primary malignancy, a high index of suspicion for cancer is required. It is crucial to carefully evaluate any liver lesion identified in these patients to ensure that indeterminate lesions are not overlooked. Effective management of benign liver lesions involves a multidisciplinary team, including hepatologists, surgeons, and radiologists, ensuring a comprehensive and individualized approach to patient care. This review outlines the clinical presentation of common benign liver lesions, providing a diagnostic and management framework. Emphasis is placed on a personalized approach to minimize patient distress and optimize outcomes by leveraging imaging advancements and multidisciplinary collaboration.

Fat-Poor Hepatic Angiomyolipoma in Noncirrhotic Livers: Imaging Features, Pathology, and Differential Diagnosis

OBJECTIVE

To investigate imaging features of fat-poor hepatic angiomyolipomas in noncirrhotic livers in order to enhance the diagnostic accuracy for this condition.

METHODS

The clinical and imaging data of 19 patients with fat-poor hepatic angiomyolipoma (fpHAML) was retrospectively analyzed.

RESULTS

Of the 19 patients without hepatitis, cirrhosis, or sarcoidosis, 16 had no clinical symptoms. There were 20 lesions in 19 patients. Macroscopic fat, calcification, hemorrhage, necrosis, and pseudocapsule were not observed in the 20 lesions. All lesions showed marked enhancement on the arterial phase, and the degree of enhancement was significantly higher than that in the adjacent hepatic parenchyma. In 8 cases, the enhancement of the portal phase was higher than that in the arterial phase. Multiple intratumor vessels were observed in the tumor, and lesions with diameters larger than 3.0 cm were more frequently observed. The degree of enhancement of 18 lesions on portal phase or delayed phase was slightly higher than or equal to that in the surrounding hepatic parenchyma. The lesions were hyperintense on diffusion-weighted imaging and showed homogeneous hypointensity on the hepatobiliary phase. Only 6 cases showed the presence of an early draining vein.

CONCLUSIONS

These imaging features have some implications for the diagnosis of fpHAML. Therefore, an increased awareness of fpHAML is needed among radiologists.

Hepatic perivascular epithelioid cell tumor: a retrospective analysis of 36 cases

Background and aims

Hepatic perivascular epithelioid cell tumor (PEComa) is a rare type of mesenchymal neoplasm and lacks systematic reports. The aim was to analyze the features of hepatic PEComa in order to provide our own experience for diagnosis and management from a single center.

Methods

We retrospectively analyzed clinical data, imaging findings, pathology, treatments and prognosis of 36 patients with hepatic PEComa in the First Affiliated Hospital of Zhengzhou University from January 2016 to September 2023.

Results

29 females and 7 males (median age, 47.8 years) were included in this study. The majority (26/36, 72.2%) of patients were diagnosed incidentally with non-specific symptoms. Abnormal enhancement of enlarged blood vessels (27/36,75%) can be observed on CT/MRI and only 7 patients (19.4%) were correctly diagnosed by imaging examinations. The positive immunohistochemical expressions were HMB-45(35/36,97.2%), Melan-A (34/35,97.1%), SMA (23/26,88.5%) and CD34(86.7%,26/30). Treatments include resection (24/36,67.7%), radiofrequency ablation (6/36,16.7%), transcatheter arterial chemoembolization(1/36,2.7%), conservative clinical follow-up(2/36,5.6%), and sirolimus-chemotherapy (3/36,8.3%). During the follow-up period (range, 2-81 months), except for one patient with a single intrahepatic recurrence and 3 malignant patients died in 6 months, the remaining patients had no signs of recurrence and metastasis.

Conclusions

Hepatic PEComa has no specific clinical features and mainly depends on clinicopathological characteristics for accurate diagnosis. Resection is the best treatment for benign PEComa, but TACE and radiofrequency ablation can also be considered in case of contraindications for surgery.

Case report: Liver PEComa after kidney transplantation in recipient with tuberous sclerosis complex

Introduction

Perivascular epithelioid cell tumors (PEComa) are rare tumors of mesenchymal origin that exhibit perivascular epithelioid cell phenotype. One of its most common localizations is uterus, whereas only a few studies reported PEComa localization as liver. There is a correlation between the presence of PEComa and tuberous sclerosis complex (TSC). TSC is a rare disease which leads to the development of mostly non-cancerous tumors in various organs. We would like to present a case of a kidney transplant recipient with a PEComa detected post-transplant in the liver.

Case report

A 27-year-old patient, 3 years after kidney transplantation (KTx) due to chronic renal failure in the course of autosomal dominant polycystic kidney disease and concomitant TSC, was admitted to the Clinic and Department of General and Transplant Surgery for abnormal findings in computed tomography (CT). A CT scan was conducted for oncological follow-up after a kidney transplant (KTx) because before the transplantation, a small cystic lesion measuring 7 mm in diameter was removed from the donor kidney and diagnosed as papillary renal cell carcinoma (PRCC). Two tumors in the liver were detected - one 27mm in diameter in segment VII/VIII and the other 8mm in diameter in segment II/III. Because of typical radiological signs hepatocellular carcinoma was suspected, but the serum level of alpha fetoprotein was within normal limits and liver function was preserved. The intraoperative biopsy and the radiofrequency ablation (RFA) of the larger tumor were performed three months later. In the histopathological examination benign PEComa (HMB45 +, Melan A +) was detected.

Conclusion

The oncological surveillance made it possible to detect liver lesion in early stage and in 3,5-year follow-up no sign of recurrence of PEComa was found. This case is the second to show RFA as treatment method of liver PEComa and first in kidney transplant recipient.

Hepatic Angiomyolipoma in Patients With Inflammatory Breast Cancer: A Case Report

Hepatic angiomyolipoma (HAML) is a rare tumor comprising adipose tissue, smooth muscle cells, and blood vessels. On the other hand, inflammatory breast cancer (IBC) is a rare and severe form of breast cancer that progresses quickly and presents as breast inflammation. It is incredibly unusual for HAML and IBC to coexist in the same patient. In the present study, we describe a case of a 63-year-old Yemeni female patient diagnosed with locally advanced left breast cancer presented with pain at the left breast and axilla. A computed tomography (CT) scan for staging showed an incidental large hepatic mass, which was eventually discovered to be HAML. The patient underwent a modified radical mastectomy after completing her neoadjuvant treatment and later underwent parenchyma-sparing liver resection of that lesion; follow-up has continued till now. The diagnosis of HAML in the presence of IBC can pose challenges due to overlapping clinical and radiological features. Treatment decisions for patients with coexisting HAML and IBC require a multidisciplinary approach; surgical resection, embolization, targeted therapies, and systemic chemotherapy may be considered based on the extent of the disease and individual patient factors. Lastly, a brief review of the related literature was also carried out.

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 With Predominant Lipomatous Component: A Rare Entity

Hepatic angiomyolipoma (HAML) is a rare benign mesenchymal tumor with varying amounts of mature adipose tissue, smooth muscle cells, and thick-walled blood vessels. We present a rare case of hepatic angiomyolipoma (AML) with predominant lipomatous components. A 42-year-old female presented to the hospital with pain in the right lumbar region. On imaging, there was a large fat-predominant mass attached to the surface of the liver extending down to the lumbar region. On small biopsy, it was reported as a well-differentiated adipocytic neoplasm, and fluorescence in situ hybridization (FISH) studies performed for MDM2 were negative. On excision, histopathological examination showed predominantly fat components, but there were few epithelioid cells between adipocytes and thick-walled blood vessels. These cells were positive for Melan-A, HMB45, and smooth muscle actin (SMA) and negative for hepatocyte paraffin-1 (Hep Par1). Angiomyolipoma is a benign tumor and has a good prognosis with surgical excision. Few cases are associated with tuberous sclerosis.

Hepatic Angiomyolipoma: A Case Report and Literature Review

Hepatic angiomyolipoma (HAML) is an uncommon primary liver tumor with limited reported cases in the literature. It is composed of varying amounts of fat, smooth muscle, and blood vessels, typically non-malignant proliferation. It usually presents diagnostic challenges due to diverse imaging characteristics. We present a case of a 50-year-old female with a small HAML causing mild abdominal pain. It displayed radiographic characteristics mimicking hepatocellular carcinoma (HCC), and subsequent diagnosis was established upon histopathological findings of liver biopsy. The patient was radiologically monitored, and then she underwent surgical resection later on because of the size increase. Follow-up showed no signs of recurrence at 3 months. This case highlights the importance of histologic diagnosis of HAML if there are suggestive imaging features, given the variety of differential diagnoses. Symptoms or tumor growth is to be considered as warning signs that should lead to surgical resection, which remains the primary treatment modality.

Transcatheter arterial embolization followed by laparoscopic anatomic hepatectomy for spontaneous rupture of a giant hepatic angiomyolipoma: a case report

Hepatic angiomyolipoma is a rare and possibly cancerous mesenchymal tumor that consists of three components: blood vessels, smooth muscle cells, and adipose tissue. In this paper, we reported a case of a 36-year-old man who had a giant hepatic angiomyolipoma with spontaneous rupture and hemorrhage. The patient was admitted to our hospital with sudden upper abdominal pain for 3 h. A giant tumor was found in the left and caudate lobes of the liver, as well as significant blood collection around the liver and in the pelvis. Hemoglobin, liver function test results, and serum tumor maker levels were all within normal ranges. To prevent bleeding, emergency angiography and embolization were performed. During angiography, it was discovered that the tumor was supplied by the left hepatic artery and had a very rich internal blood supply. A massive left hepatic mass of about 11 cm in diameter was found bulging from the surface of the liver and rupturing there during laparoscopic exploration a week later. The rupture was strongly adhered to the smaller curvature of the stomach. The patient underwent laparoscopic left hemihepatectomy and caudate lobectomy, and the tumor specimen was brown, with clear boundaries with the surrounding normal liver parenchyma, and there were a large number of necrotic lesions inside the tumor. Histopathological results confirmed the mass as hepatic angiomyolipoma with negative resection margins. Immunohistochemical staining indicated that the tumor had positive homatropine methylbromide-45. After 13 months of follow-up, no tumor recurrence or metastasis occurred in the patient.

TSC2 inactivation, low mutation burden and high macrophage infiltration characterise hepatic angiomyolipomas

AIMS

Although TSC1 or TSC2 inactivating mutations that lead to mTORC1 hyperactivation have been reported in hepatic angiomyolipomas (hAML), the role of other somatic genetic events that may contribute to hAML development is unknown. There are also limited data regarding the tumour microenvironment (TME) of hAML. The aim of the present study was to identify other somatic events in genomic level and changes in TME that contribute to tumorigenesis in hAML.

METHODS AND RESULTS

In this study, we performed exome sequencing in nine sporadic hAML tumours and deep-coverage targeted sequencing for TSC2 in three additional hAML. Immunohistochemistry and multiplex immunofluorescence were carried out for 15 proteins to characterise the tumour microenvironment and assess immune cell infiltration. Inactivating somatic variants in TSC2 were identified in 10 of 12 (83%) cases, with a median allele frequency of 13.6%. Five to 18 somatic variants (median number: nine, median allele frequency 21%) not in TSC1 or TSC2 were also identified, mostly of uncertain clinical significance. Copy number changes were rare, but detection was impaired by low tumour purity. Immunohistochemistry demonstrated numerous CD68+ macrophages of distinct appearance from Küpffer cells. Multiplex immunofluorescence revealed low numbers of exhausted PD-1+/PD-L1+, FOXP3+ and CD8+ T cells.

CONCLUSION

hAML tumours have consistent inactivating mutations in TSC2 and have a low somatic mutation rate, similar to other TSC-associated tumours. Careful histological review, standard IHC and multiplex immunofluorescence demonstrated marked infiltration by non-neoplastic inflammatory cells, mostly macrophages.

Epithelioid hepatic angiomyolipoma in pregnancy: A case report

INTRODUCTION AND IMPORTANCE

Epithelioid hepatic angiomyolipoma (HAML) is a rare benign tumor predominantly found in women. Its occurrence during pregnancy is extremely rare. Accurate diagnosis of HAML is challenging due to its radiological resemblance to other hepatic neoplasms. We present a case of epithelioid HAML in a pregnant patient, highlighting the diagnostic and management challenges encountered.

CASE PRESENTATION

A 24-year-old pregnant female, in her fifth month of pregnancy, presented with right hypochondrium pain and nausea. Radiological imaging suggested the possibility of a hepatic adenoma. The patient opted to continue the pregnancy with regular monitoring of the mass as well as fetal health. After delivering a healthy baby, the patient underwent successful mass excision and cholecystectomy. Histopathology of the liver mass confirmed the diagnosis of epithelioid HAML.

CLINICAL DISCUSSION

Epithelioid HAML is a rare tumor often misdiagnosed. It is more aggressive and frequently associated with tuberous sclerosis complex (TSC) compared to other subtypes. The diagnosis of HAML can be challenging due to its resemblance to Hepatocellular Carcinoma and other hepatic neoplasms on radiological imaging. Immunohistochemistry plays a crucial role in confirming the diagnosis. Surgical excision is the recommended treatment, with complete removal to minimize the risk of recurrence.

CONCLUSION

This case report highlights the rarity of epithelioid HAML during pregnancy and emphasizes the importance of a multidisciplinary approach in managing hepatic neoplasms. Close monitoring is crucial, considering the potential risks to the mother and fetus. Accurate diagnosis through histopathological evaluation, immunohistochemistry and a multidisciplinary approach are essential for appropriate management.

Differentiation between hepatic angiomyolipoma and hepatocellular carcinoma in individuals who are not at-risk for hepatocellular carcinoma

PURPOSE

To develop a practical methodfor differentiating hepatocellular carcinoma (HCC) from angiomyolipoma (AML) in individuals who are not at-risk for HCC.

METHOD

We retrospectively enrolled consecutive patients who underwent gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) and pathological confirmation between January 2008 and April 2022. Patients who underwent prior treatment, those with multiple lesions, or those at-risk for HCC were excluded. The training cohort included patients with pathological confirmation between 2008 and 2019, whereas the validation cohort included the remaining cases. Independent reviews of the MRI were performed by two reviewers. Using the clinical and MRI findings, we developed AML-HCC score using Firth's logistic regression in the training cohort, and the diagnostic performance was validated in the validation cohort.

RESULTS

Of the 206 patients, 156 were assigned to the training cohort (25 and 131 patients with AML and HCC, respectively) and 50 were assigned to the validation cohort (4 and 46 patients with AML and HCC, respectively). The AML-HCC score was defined as the sum of female (score 1), early draining vein (score 2), T2 homogeneity (score 1), necrosis or severe ischaemia (score -2), and HBP hyperintensity to spleen (score -1). When the AML-HCC score was ≥1, the sensitivity and specificity were 80% and 95% for the training cohort and 100% and 80% for the validation cohort, respectively.

CONCLUSIONS

We developed and validated an AML-HCC score to differentiate between AML and HCC in individuals who are not at-risk for HCC, and our model demonstrated good diagnostic performance.

A rare case of giant hepatic angiomyolipoma with subcapsular rupture

Hepatic angiomyolipoma (HAML) is a rare mesenchymal neoplasm that predominantly affects middle-aged women. In this study, we present a case of a 49-year-old woman with a giant HAML accompanied by spontaneous subcapsular rupture. The patient initially experienced nausea and abdominal distention, followed by an enlargement of the upper abdominal circumference. Laboratory examination revealed decreased serum hemoglobin, while tumor biomarkers were within normal ranges. Imaging studies, such as abdominal ultrasound and contrast-enhanced computed tomography (CT), demonstrated a large upper abdominal mass with heterogeneous density and hypervascularity. The tumor appeared to have invaded the left liver, raising concerns about possible malignancy. Subsequent positron-emission tomography/CT confirmed increased fluorodeoxyglucose uptake in the mass. Laparoscopic exploration revealed a protruding, well-encapsulated tumor from the left liver, exhibiting subcapsular hemorrhage. Surgical resection of the tumor and the left liver was performed, leading to a successful outcome.

[Angiomyolipoma of the liver]

Angiomyolipoma of the liver is an extremely rare neoplasm, the number of reported cases of this disease is only about 600 worldwide. Morphological criteria for neoplasm verification present difficulties due to low occurrence and complexity of differential diagnostic search. In this regard, this observation is of interest to pathologists and physicians. A special feature of this tumor is the presence of three components: adipose, vascular and muscular with characteristic epithelioid cells. The article presents the clinical and morphological characteristics of liver angiomyolipoma in a 40-year-old woman. The diagnosis was confirmed by immunohistochemical study: a positive reaction with HMB45, Melan A, SMA, desmin, CD31, CD34; proliferative index was more than 25%.

Case Report: Perivascular epithelioid tumors of the gastrointestinal tract

Background

Perivascular epithelioid cell tumor of the gastrointestinal tract (GI PEComa) is a rare mesenchymal neoplasm. GI PEComa is mostly observed in the colon and has a marked middle-aged female predominance. PEComa has no typical clinical or imaging manifestations or endoscopic characteristics. Therefore, the diagnosis of this disease mostly relies on pathological findings. HMB-45 is a sensitive immune marker of PEComa.

Case presentation

We reported a case of a middle-aged female with sigmoid colon PEComa. To exclude carcinogenesis, the large basal polyp in the sigmoid colon was removed by endoscopic mucosal resection (EMR). Immunohistochemistry analysis results showed that this lesion expressed HMB-45, which is a characteristic melanin marker of PEComa. Finally, the lesion was diagnosed as sigmoid colon PEComa. At the time of submission of this report, surgical resection was the primary treatment for PEComa. Though the characteristics of tumor biology and clinical behavior in PEComa are not clear, the boundary is clear, and the tumor can be completely removed. However, close follow-up is required after the surgery because of the lesion's undetermined benign and malignant nature.

Conclusion

The present case study emphasizes the importance of pathological diagnosis. Therefore, upon finding gastrointestinal polyps with a mucosal ulcer under endoscopy, the GI PEComa diagnosis should be considered. It is necessary to detect the characteristic melanin markers of PEComa. Due to the rarity of these cases, challenges are faced in diagnosing and treating PEComa.

Perivascular epithelioid cell tumors of the liver misdiagnosed as hepatocellular carcinoma: Three case reports

BACKGROUND

Hepatic perivascular epithelioid cell neoplasms (PEComas) are rare. Diagnostic and treatment experience with hepatic PEComa remains insufficient.

CASE SUMMARY

Three hepatic PEComa cases are reported in this paper: One case of primary malignant hepatic PEComa, one case of benign hepatic PEComa, and one case of hepatic PEComa with an ovarian mature cystic teratoma. During preoperative imaging and pathological assessment of intraoperative frozen samples, patients were diagnosed with hepatocellular carcinoma (HCC), while postoperative pathology and immunohistochemistry subsequently revealed hepatic PEComa. Patients with hepatic PEComa which is misdiagnosed as HCC often require a wider surgical resection. It is easy to mistake them for distant metastases of hepatic PEComa and misdiagnosed as HCC, especially when it's combined with tumors in other organs. Three patients eventually underwent partial hepatectomy. After 1-4 years of follow-up, none of the patients experienced recurrence or metastases.

CONCLUSION

A clear preoperative diagnosis of hepatic PEComa can reduce the scope of resection and prevent unnecessary injuries during surgery.

Primary hepatic epithelioid angiomyolipoma: a small case series

BACKGROUND

Hepatic epithelioid angiomyolipomas (HEAMLs) are rare and usually arise in case reports, and thus, we aimed to study the clinicopathological features, treatment and prognosis of these lesions.

METHODS

We identified patients from institutional database with HEAMLs and retrospectively collected clinical data.

RESULTS

Of 12 patients, 10 were females, and the median age was 49 years. A liver mass was found on chance upon routine health screening in nine patients. Imaging features included clear border (9/12), internal heterogeneity (8/12), arterial enhancement (12/12), fat (5/12), intra-tumour vessel (3/12), draining hepatic vein (2/12) and pseudocapsule (1/12). The preoperative diagnoses contained HEAML (n = 5), hepatocellular carcinoma (n = 6), and hepatic cystadenocarcinoma (n = 1). All cases had received surgery and obtained a negative margin. All specimens showed positive findings for HMB-45 and Melan A. No tumour recurrence or mortality was described with a mean follow-up time of 23.5 months.

CONCLUSIONS

HEAML is a low potential malignancy tumour that frequently appears in middle-aged females. It has nonspecific symptoms and may present special imaging features including intra-tumour vessel, early draining hepatic vein and lack of a pseudo capsule. The lesion is confirmed by pathological and immunohistochemical findings. Surgery and subsequent long-term follow-up are the most appropriate management approaches.

Hepatic perivascular epithelioid cell tumor: A case report

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor with histologic and immunophenotypic characteristics of perivascular epithelioid cells, has a low incidence, and can involve multiple organs. PEComa originating in the liver is extremely rare, with most cases being benign, and only a few cases are malignant. Good outcomes are achieved with radical surgical resection, but there is no effective treatment for some large tumors and specific locations that are contraindicated for surgery.

CASE SUMMARY

A 32-year-old woman was admitted to our hospital with a palpable abdominal mass and progressive deterioration since the previous month. An ultrasound-guided percutaneous liver aspiration biopsy was performed. Postoperative pathological immunohistochemical staining was HMB45, Melan-A, and smooth muscle actin positive. Perivascular epithelioid tumor was diagnosed. The tumor was large and could not be completely resected by surgery. Further digital subtraction angiography revealed a rich tumor blood supply, and interventional embolization followed by surgery was recommended. Finally, the patient underwent transarterial embolization (TAE) combined with sorafenib for four cycles. Angiography reexamination indicated no clear vascular staining of the tumor, and the tumor had shrunk. The patient was followed up for a short period of time, achieved a stable condition, and surgery was recommended.

CONCLUSION

Adjuvant combination treatment with TAE and sorafenib is safe and feasible as it shrinks the tumor preoperatively and facilitates surgery.

Giant hepatic angiomyolipoma presenting with severe anemia: A surgical case report and review of literature

Background

Angiomyolipoma (AML) is a solid benign neoplasm with mesenchymal features. The clinical signs and symptoms of hepatic angiomyolipoma are nonspecific, and treatment strategy is variable.

Presentation

A 35-years-old male patient has admitted to the hospital with symptoms of severe anemia. Abdominal multi-slice computed tomography (MSCT) and Gadoxetic acid (GA)-enhanced magnetic resonance imaging (MRI) revealed a heterogeneous 23 × 17 cm-in-sized tumor with heterogeneous enhancement and increased angiogenesis. Percutaneous hepatic biopsy was proceeded and in immunohistochemistry, tumor cells responded positively to the HMB-45, SMA, and Glutamine stains, the CD-34 stain was positive for blood vessels as well as Ki-67 sporadically positive, but the Heppar1, S-100, CK stains reacted negative. The final pathologic result was consistent with the primary hepatic angiomyolipoma. The final surgical management was extended right hepatectomy with ligation of the right hepatic artery (RHA) and vein (RHV), as well as the middle hepatic vein (MHV), one month after portal embolization as well as to enlarge the remnant liver volume.

Discussion

A hepatic angiomyolipoma (HAML) primary origin is relatively rare, the clinical manifestations are variable and non-specific. Histological examination and immunohistochemistry staining are considered as the gold standard for HAML diagnosis. HAML are commonly expressed benign behaviors, but HAML cases with malignant behaviors were reported in a cumulative incidence. Radical surgery must be still the most effective and major treatment approach.

Conclusion

The present case being the first case with initial syndrome of severe anemia accounted in the English literature. Giant angiomyolipoma is composed of blood vessels and could lead to extensive internal tumoral hemorrhage. We here present a report of this case with had primary hepatic angiomyolipoma with clinical picture of severe anemia.

•

A hepatic angiomyolipoma (HAML) is occasionally rare, the clinical manifestations are variable and non-specific.

•

Histological examination and immunohistochemistry staining are considered as the gold standard.

•

Radical surgery is the most effective and major treatment approach for symptomatic or big-sized HAML.

Ultrasound contrast agent Sonazoid for the diagnosis of hepatic epithelioid angiomyolipoma: a case report

Background

An angiomyolipoma usually occurs in the kidneys and rarely in the liver. Hepatic epithelioid angiomyolipoma (HEAML), a rare variant of angiomyolipoma, possesses malignant potential and mimics the imaging features of hepatocellular carcinoma. Sonazoid® (perfluorobutane microbubbles), a new contrast agent that facilitates hepatic parenchyma-specific Kupffer phase imaging on contrast-enhanced ultrasonography (CEUS), is useful for the detection and characterization of focal liver lesions.

Case presentation

A 30-year-old man with HEAML underwent CEUS using Sonazoid®, in which new concepts for ultrasonography-based differentiation between HEAML and hepatocellular carcinoma were applied.

Conclusions

This case report provides clinicians and radiologists with a reference for distinguishing HEAML from hepatocellular carcinoma based on CEUS using Sonazoid®.

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.

Clinical and Contrast-enhanced Ultrasound Characteristics of Epithelioid and Classic Hepatic Angiomyolipoma: Comparison With Alpha-fetoprotein-negative Hepatocellular Carcinoma

Hepatic angiomyolipoma (HAML) comprises epithelioid angiomyolipoma (EAML) and classic hepatic angiomyolipoma (CAML). The imaging appearance of HAML varies widely, and EAML is more easily misdiagnosed as hepatocellular carcinoma (HCC) than as CAML. The clinical and contrast-enhanced ultrasound (CEUS) features of CAML, EAML and HCC with negative alpha-fetoprotein protein expression (HCC[AFP-]) were retrospectively reviewed. The hyper-vascular type was more commonly found in CAML and EAML lesions than in HCC lesions. Most lesions were hyper-enhanced in the arterial phase. CAMLs showed prolonged hyper-enhancement or iso-enhancement during the portal and late phases on CEUS, making them easily distinguishable from HCC(AFP-). Some EAML lesions (41.7%) were hypo-echoic, similar to HCC(AFP-). However, the hypo-enhancement of EAML lesions occurred later than that of HCC(AFP-) lesions. Thus, our findings may be useful in distinguishing among these lesions to improve diagnostic accuracy.

Huge Hepatic Angiomyolipoma Mimicking Low Grade Hepatocellular Carcinoma

A 41-year-old man was diagnosed with a huge symptomatic liver mass and was referred to our hospital for liver biopsy and further evaluation. He presented with right upper quadrant tenderness. Enhanced abdominal computed tomography and magnetic resonance imaging revealed a 12.5-cm relatively well-defined heterogeneous enhancing mass in the right inferior liver with a large exophytic component containing a fat component and progressive delayed enhancement. The patient underwent right inferior sectionectomy. The pathological diagnosis was confirmed as angiomyolipoma, 12.3×9.2×5.0 cm in size, with tumor necrosis in 20% of the tissue. Hepatic angiomyolipoma is known as a benign tumor, but in our case, because of the large tumor size and coagulative necrosis, this tumor had malignant potential; surgical resection was deemed to be appropriate, and close follow-up monitoring was essential postoperatively.

Laparoscopic hepatectomy for hepatic angiomyolipoma with preoperative diagnosis of other malignancy: a report of 2 cases

Background

Hepatic angiomyolipoma (HAML) is a rare liver tumor, and hepatectomy is the only effective treatment. Due to the difficulty of correct diagnosis of HAML before surgery by image studies, more than 36.6% of reported HAMLs are misdiagnosed as other malignant liver tumors before surgery. As there are only few reported cases in which HAMLs were removed using laparoscopic hepatectomy, the effectiveness of laparoscopic hepatectomy for such HAMLs in which are diagnosed as other malignant liver tumor before surgery has not been reported.

Case presentation

Case 1: a 58-year-old female with a history of treatment for autoimmune hepatitis was preoperatively diagnosed with hepatocellular carcinoma (size: 20 mm) in segment 7 (S7) of the liver. The tumor was removed by laparoscopic partial resection and was diagnosed as a HAML through a pathological examination. The patient’s postoperative course was good, and she was recurrence-free at 37 months after the hepatectomy. Case 2: a 29-year-old female with a history of surgery for a right mature cystic teratoma was referred to our department to receive treatment for a growing 20-mm liver tumor with some calcification, which arose in S3 of the liver. A metastatic liver tumor derived from the mature cystic teratoma was suspected, and laparoscopic left lateral sectionectomy was performed. The liver tumor was diagnosed as a HAML after a pathological examination. The patient’s postoperative course was unremarkable, and more than 54 months have passed since the hepatectomy without any recurrence.

Conclusions

Two cases in which HAMLs were preoperatively diagnosed as other malignant liver tumor were successfully removed by laparoscopic hepatectomy with a correct postoperative diagnosis. Laparoscopic hepatectomy for the present 2 cases of HAML seemed to be effective for providing a correct diagnosis after the curative removement of liver tumor with a smaller invasion compared to open hepatectomy, and for denying risk of dissemination of the malignant tumor by needle biopsy that had to be considered before ruling out malignant tumor.

RESSECÇÃO LAPAROSCÓPICA DE TUMORES BENIGNOS DO FÍGADO: POSIÇÃO ATUAL

The main indications of the use of laparoscopic liver surgery (LLS), in the early days, were benign liver lesions. As LLS became more popular, indications for malignant diseases outnumbered those for benign ones. This study aims to rule out the indications and results of LLS for the treatment of benign liver tumors.

Hepatic angiomyolipoma: A case report and literature review

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HAML is a rare mesenchymal liver tumour which belongs to the family of perivascular epithelioid cell tumours.

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HAML is typically composed of blood vessels, smooth muscle, and adipose cells.

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HAML is characteristically positive for HMB-45.

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In patients with symptoms, uncertain diagnosis, or tumour growth, surgical resection should be performed.

Introduction

Hepatic angiomyolipoma (HAML) is a rare mesenchymal liver tumour which belongs to the family of perivascular epithelioid cell tumours (PEComas). It is typically composed of blood vessels, smooth muscle, and adipose cells, and shows strong immunoreactivity for HMB-45.

Presentation of the case

A 57-year-old woman was referred to our hospital with an unclear liver lesion. A fine needle biopsy revealed a suspicion of hepatic angiomyolipoma with extramedullary haematopoiesis. Preoperative imaging revealed a tumour 17 cm in diameter in the left liver lobe segments II and III. A lobectomy of the left lobe segments II and III was performed. The pathological diagnosis of hepatic angiomyolipoma was obtained.

Discussion

Variations in the predominance of the tissue components in HAML impedes diagnosis based on imaging alone. The most promising evidence of HAML is the histological identification of lipomatous, myomatous, and angiomatous tissue combined with immunohistochemical positivity for HMB-45. Although the tumour is considered benign, some cases have been described with malignant behaviour. Surgical resection should be considered in case of symptoms, inconclusive biopsy, or growth in follow-up. Other surgical indications may include aggressive patterns such as vascular invasion, p53 immunoreactivity, or rapidly proliferating tumour cells.

Conclusion

HAML is a rare liver tumour. In patients with symptoms, uncertain diagnosis, or tumour growth, surgical resection should be performed according to oncological criteria.

Hepatic Angiomyolipoma: Clinical Features and Imaging Findings of Quantitative Contrast-Enhanced Ultrasound Perfusion Analysis and Magnetic Resonance Imaging

OBJECTIVES

To investigate whether quantitative contrast-enhanced ultrasound (CEUS) analysis and magnetic resonance imaging (MRI) can differentiate hepatic angiomyolipoma (AML) from hepatocellular carcinoma (HCC) and hepatic epithelial angiomyolipoma (EAML) from nonepithelial AML.

METHODS

Retrospective analysis of 26 CEUS lesions pathologically confirmed as AML and 60 patients with confirmed HCC. Clinical and ultrasound (US) features of AML versus HCC and EAML versus nonepithelial AML were analyzed. Quantitative parameters, including arrival time, ascending slope, time to peak, peak intensity (PI), fall time (FT), and mean transit time (MTT), were analyzed. Diagnostic performance of MRI and CEUS was compared.

RESULTS

Angiomyolipoma was significantly different from HCC in US findings of solitary tumor (P < .001), well-defined border (P = .025), and hyperechogenicity (P < .001). Tumor types were significantly different in US findings of centripetal filling pattern (P < .001), less hypoenhancement in the CEUS delayed phase (P = .04), high PI (P = .007) and ascending slope (P = .006), and short FT (P = .001) and MTT (P < .05). The sensitivity and specificity of quantitative parameters were 61.5% to 96.2% and 55.0% to 71.7% (area under the curve, 0.642-0.773). An early draining vein and tumor vessels, intratumor fat, absence of pseudocapsules, mild signal intensity on diffusion-weighted imaging, and hypointensity in the MRI delayed phase were helpful for differentiation of AML from HCC (P < .05). The positive predictive values of CEUS and MRI were 46.3% to 100% and 42.9% to 75%, with no significant difference (P > .05). Epithelial AML was more likely to be hypoechoic with a centripetal filling pattern than nonepithelial AML (P < .05). The MTT and FT of EAML were shorter than those of nonepithelial AML (P < .05). The PI of EAML was significantly stronger than that of nonepithelial AML (P < .01). The sensitivity and specificity of quantitative parameters were 68.7% to 100.0% and 60.0% to 100.0% (area under the curve, 0.825-0.941). Less intratumor fat was helpful for differentiation of EAML from nonepithelial AML (P < .05). The positive predictive values of CEUS and MRI were 77.8% to 100% and 85.7%, with a significant difference (P < .05).

CONCLUSIONS

Quantitative CEUS findings could be valuable in differentiating EAML from HCC.

Hepatic nodules with arterial phase hyperenhancement and washout on enhanced computed tomography/magnetic resonance imaging: how to avoid pitfalls

This essay aimed to illustrate the various hepatic nodules that may exhibit arterial phase hyperenhancement and washout on computed tomography/magnetic resonance imaging (CT/MRI). Hepatic nodules with arterial phase hyperenhancement and washout on CT/MRI include hepatocellular carcinoma, focal nodular hyperplasia-like nodules, serum amyloid A-positive hepatocellular neoplasms, intrahepatic cholangiocarcinoma, intrahepatic bile duct adenoma, hepatoblastoma, hepatocellular adenoma, hepatic epithelioid angiomyolipoma, and metastasis including neuroendocrine and gastrointestinal stromal tumors. Understanding the imaging findings is important to ensure correct diagnosis.

[Angiomyolipoma of the liver-a case report and review of the literature]

We report the case of a 70-year-old female patient with an unclear liver mass after clinical and radiological evaluation. In histopathological evaluation, we diagnosed a hepatic angiomyolipoma, which is a rare entity and belongs to the perivascular epithelioid group of tumours (PEComa). In this report, we illustrate the typical histomorphology, immunohistochemical profile and molecular changes based on the case presentation and discuss and review the current literature on hepatic angiomyolipomas. In addition, typical differential diagnostic problems are highlighted.

Abdominal perivascular epithelioid cell tumor (PEComa) without visible fat: a clinicopathologic and radiological analysis of 16 cases

OBJECTIVE

To retrospectively review the clinicopathological features and computed tomography (CT) and magnetic resonance imaging (MRI) findings of abdominal perivascular epithelioid cell tumor without visible fat (PEComa_wvf).

MATERIALS AND METHODS

Sixteen patients with surgically and pathologically confirmed perivascular epithelioid cell tumor without visible fat were enrolled. Their clinicopathological data and imaging findings were retrospectively reviewed. The CT and MRI features, including location, size, shape, margin, density, calcification, cystic necrosis and enhancement pattern, were analyzed.

RESULTS

There were 4 males and 12 females (median age, 46 years; range, 21-65 years) in this study. All 16 patients were diagnostic asymptomatic unenhanced CT or MRI and revealed a well-defined (n = 13), oval (n = 10), mass with heterogeneous (n = 6) or homogeneous density/signal intensity (n = 7), calcification and hemorrhage was no found in any cases. On enhanced CT/MRI, markedly enhancement patterns (n = 14) were observed. The "peripheral enhancement" sign was observed in 13 cases. One in 16 cases recurrence was discovered during the follow-up period.

CONCLUSIONS

Dynamic CT, MRI and pathology of PEComa_wvf had some characteristics of non-aggressive pattern of performance, and MRI would provide beneficial detection of microscopic fat. Enhanced imaging showed PEComa_wvf is characterized by a "peripheral enhancement" with a marked enhancement pattern. Knowing these characteristics could contribute to improving the understanding abdominal PEComa_wvf and related palliative care.

Contrast-Enhanced Ultrasound Findings and Differential Diagnosis of Hepatic Epithelioid Angiomyolipoma Compared with Hepatocellular Carcinoma

Hepatic epithelioid angiomyolipoma (EAML) has malignant potential that can easily be misdiagnosed as hepatocellular carcinoma (HCC), but the treatment options of these conditions are different. This retrospective study investigated whether contrast-enhanced ultrasound (CEUS) can differentiate EAML from HCC. We included 24 patients with pathologically confirmed EAML and 36 patients with HCC who underwent pre-operative conventional ultrasound and CEUS. The conventional ultrasound and CEUS features of the two groups were analyzed. Time intensity curves (TICs) were analyzed for all lesions using quantitative perfusion analysis software. This study found that significant differences existed between the EAML and HCC groups in terms of clinical features such as sex, age, symptoms, alpha-fetoprotein and history of hepatitis B virus infection (p < 0.05). Tumor size, number, border and echogenicity on conventional ultrasound were significantly different between EAML and HCC (p < 0.05). Regarding CEUS, EAML was more likely to have a centripetal enhancement pattern than HCC (p < 0.05). The tumor enhancement degree in the delayed phase in CEUS was significantly different between EAML and HCC (p < 0.05). Quantitative analysis of CEUS parameters revealed that the wash-in area under the curve (AUC) was larger in EAML than in HCC (p < 0.05). Time to peak was significantly shorter in EAML than in HCC (p < 0.05). The peak intensity was significantly stronger in EAML than in HCC (p < 0.05). Regarding the diagnostic performance of CEUS parameters that showed statistical significance on univariate analysis, the sensitivity and specificity for distinguishing EAML from HCC was 66.7%-100.0% and 55.6%-91.7%, respectively. Overall, CEUS could be valuable in differentiating EAML from HCC. Specific features such as the centripetal filling and prolonged enhancement patterns on CEUS, higher peak intensity, bigger wash-in AUC and shorter time to peak on TICs may contribute to a more confirmative differential diagnosis of EAML.

Contrast-enhanced sonographic appearances of two primary hepatic epithelioid angiomyolipomas

Epithelioid hepatic angiomyolipoma (Epi-HAML) is a rare hepatic tumor frequently misdiagnosed as hepatocellular carcinoma (HCC). Unlike conventional angiomyolipoma (AML), Epi-HAML contains minimal amount of adipose tissue, which is a radiological distinguishing feature between AML and HCC. Two patients were referred for management of incidentally found hepatic lesions confirmed to be Epi-HAML on post-resection tissue analysis. CT and MRI findings were suggestive of HCC. Contrast-enhanced ultrasound demonstrated intratumoral shunting, a feeding artery, and early draining hepatic vein. These findings should alert radiologists to the possibility of Epi-HAML. Furthermore, these features may be better assessed by contrast-enhanced ultrasound due to its superior dynamic temporal resolution.

Comparison of hepatic epithelioid angiomyolipoma and non-hepatitis B, non-hepatitis C hepatocellular carcinoma on contrast-enhanced ultrasound

PURPOSE

The purpose of this study was to retrospectively compare the imaging features of hepatic epithelioid angiomyolipoma (HEAML) to those of hepatocellular carcinoma negative for hepatitis B surface antigen and hepatitis C antibody (NBNC-HCC) on contrast-enhanced ultrasound (CEUS) with sulphur hexafluoride microbubbles.

MATERIAL AND METHODS

Twenty-two patients (4 men, 18 women) with a mean age of 42.6±10.2 (SD) years (range: 22-63 years) with histopathologically confirmed HEMAL were included in the study. Forty-four patients (30 men, 14 women) with a mean age of 57.3±15.9 years (range: 19-85 years) with histopathologically confirmed NBNC-HCC were randomly selected from our institution's database as a control group. The CEUS characteristics of the two groups were compared.

RESULTS

On conventional ultrasound, significant differences in tumor diameter were found between HEAML (4.0±2.0 [SD] cm; range: 1.3-8.9cm) and NBNC-HCC (8.4±4.4 [SD] cm; range: 1.6-18cm) (P<0.001) as well as in degrees of enhancement during the portal (P=0.001) and late phases (P=0.003), contrast distribution (P<0.001) and absence of pseudocaspule (P<0.001). On CEUS, hyperenhancement during the arterial phase was observed in 21/22 (95.5%) HEAMLs and in 43/44 (97.7%) NBNC-HCCs (P>0.999). Homogeneous enhancement was more frequent in HEAMLs (20/22; 90.9%) than in NBNC-HCCs (13/44; 29.6%) (P<0.001). Pseudocapsule was observed in 0/22 HEAMLs (0.0%) and in 36/44 NBNC-HCCs (81.8%) (P=0.017). A prolonged enhancement was observed in 5/22 HEAMLs (22.7%) and in 0/44 NBNC-HCCs (0.0%) (P<0.001) during the late phase.

CONCLUSION

CEUS with sulphur hexafluoride microbubbles is helpful in discriminating between HEAML and NBNC-HCC. Homogeneous enhancement and lack of pseudocapsule are suggestive features for the diagnosis of HEAML.

Hepatic angiomyolipoma: an international multicenter analysis on diagnosis, management and outcome

BACKGROUND

Hepatic angiomyolipoma (HAML) may easily be misdiagnosed as a malignancy. The study aim was to assess diagnostic dilemmas, clinical management and outcome of this rare tumor.

METHODS

This retrospective international multicenter study included all patients with pathologically proven HAML diagnosed between 1997 and 2017. Data on patient characteristics, diagnostic work-up, management and follow-up were analyzed.

RESULTS

Thirty-eight patients were included, 32 female. Median age was 56yrs (i.q.r. 43-64) and median HAML-diameter was 57.5 mm (i.q.r. 38.5-95.3). Thirty patients had undergone CT and 27/38 MRI of the liver, diagnostic biopsy was performed in 19/38. Initial diagnosis was incorrect in 15/38 patients, of which 13 were thought to have malignancy. In 84% biopsy resulted in a correct preoperative diagnosis. Twenty-nine patients were managed with surgical resection, 4/38 with surveillance and 3/38 with liver transplantation. Recurrence after resection occurred in two cases. No HAML related deaths or progression to malignancy were documented.

CONCLUSION

HAML diagnosis proved problematic even in hepatobiliary expertise centers. Biopsy is indicated and may provide valuable additional information when HAML diagnosis is considered on cross-sectional imaging, especially when surgical resection imposes a risk of complications. Conservative management with regular imaging follow-up might be justified when biopsy confirms (classic type) HAML.

State-of-the-art MR Imaging of Fat-containing Focal Lesions of the Liver

BACKGROUND

Fat can be identified in numerous liver lesions, and usually is not a specific finding. Distinguishing between different kinds of fatty deposits is an important part of differential diagnosis. Magnetic Resonance Imaging (MRI) is superior to other imaging techniques because it allows distinguishing intracellular from macroscopic fat.

DISCUSSION

Intracellular lipid may be found in focal hepatic steatosis, hepatic adenoma, hepatocellular carcinoma and, less commonly, in focal nodular hyperplasia as well as regenerative and dysplastic nodules. Macroscopic fat is seen in angiomyolipoma, lipoma, metastases from fatcontaining neoplasms, primary or metastatic liposarcoma, hydatid cyst, pseudolipoma of the Glisson capsule, pericaval fat collection, lipopeliosis, hepatic teratoma, focal hepatic extramedullary haematopoiesis and adrenal rest tumour.

CONCLUSION

Liver nodules should be characterised with regard to underlying liver condition, MRI characteristics and contrast enhancement pattern, including hepatobiliary phase. In many cases, identification of fatty content may help narrowing the differential diagnosis.

[Abdominal pain and unclear focal liver lesion in 46-year-old female patient]

A 46-year-old woman presented with recurrent right upper quadrant pain. Abdominal ultrasound revealed an inhomogeneous liver lesion (4 × 7 cm) with complex echotexture. Since further contrast-enhanced imaging tests were inconclusive and lesion integrity remained unclear, a left hemihepatectomy was performed. Histological examination revealed a hepatic epithelioid angiomyolipoma. Hepatic epithelioid angiomyolipoma is a rare, mostly benign, mesenchymal hepatic tumor, composed of smooth muscle cells, adipose tissue, and blood vessels of varying proportions, and its correct diagnosis remains a clinical challenge.

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.

Hepatic Epithelioid Angiomyolipoma Treated with Laparoscopic Resection: Case Report and Review of the Literature

Hepatic angiomyolipoma is a rare primary liver tumor, with a radiographic appearance very similar to hepatocellular carcinoma. We present the case of a noncirrhotic patient with a liver tumor suspicious for HCC by imaging features. Liver biopsy demonstrated angiomyolipoma, and the patient successfully underwent a laparoscopic liver resection.