Malignant potential of hepatic angiomyolipoma: case report and literature review

Malignant perivascular epithelioid cell neoplasm in the liver: report of a pediatric case

Background

Perivascular epithelioid cell neoplasm (PEComa) in a child is very rare. We herein report the first malignant case of PEComa developing in the liver of a pediatric patient.

Case presentation

A 10-year-old boy visited a private clinic with prolonged fever of unknown etiology. Abdominal ultrasonography was performed to evaluate the fever’s origin, revealing a large tumor in the liver. He was thus referred to a nearby hospital to investigate the tumor further. Enhanced computed tomography (CT) showed a 6.8 × 5.9 × 10.5-cm solid lesion on S4 and S5. On magnetic resonance imaging (MRI), the tumor had a low signal intensity on T1 imaging and high signal intensity on T2 imaging, with partial diffusion restriction. ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed a marked uptake in the mass lesion with no evidence of metastasis. The patient was negative for all tumor markers, including AFP, CEA and PIVKA-II. The results of a needle biopsy suggested hepatocellular carcinoma. The tumor’s rapid growth suggested malignancy. Hepatic segmentectomy (S4 + S5 + S8) was performed. The tumor was resected en bloc with a margin. Microscopically, the tumor showed atypical spindle, polygonal or oval-shaped cells with a high nuclear grade, and vascular invasion. Immunohistochemistry was positive for alpha-smooth muscle antigen (α-SMA), human melanin black-45 (HMB-45) and melan A. The pathological diagnosis was malignant PEComa. In the 6 months after surgery, the patient complained of shoulder pain. MRI showed a dumbbell-shaped tumor at the 2nd thoracic vertebrae, which was confirmed to be bone metastasis of PEComa. After chemotherapy, including ifosfamide and doxorubicin, vertebrectomy was performed. Two years later, thoracoabdominal CT showed a 10-cm solid mass occupying the pelvis and a 15-mm nodule in the middle lobe of the right lung. Under a diagnosis of peritoneal and lung metastases, they were surgically removed and metastasis of PEComa was pathologically confirmed. Four months after the 2nd relapse, pelvic metastasis appeared again and mTOR (mammalian target of rapamycin) inhibitor was initiated. To our knowledge, this is the first report of malignant hepatic PEComa in a pediatric patient.

Conclusion

Although extremely rare, malignant hepatic PEComa can develop in a child.

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

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

Perivascular epithelioid cell tumor outgrowth from the liver

INTRODUCTION

Perivascular epithelioid celltumor (PEComa) is a rare mesenchymal neoplasia and can be found in various body sites. On the other hand, hepatic PEComa is very rare, with only a few studies having reported hepatic malignant PEComa. There is no gold standard regarding the use of diagnostic imaging studies. The diagnosis of hepatic PEComa is made by a positive immunohistochemical staining for HMB45 and Melan A. Herein, we discussed the therapeutic and follow-up process of a symptomatic hepatic PEComa case.

PRESENTATION OF CASE

A 22-year-old woman presented with a palpable mass in abdomen. A computerized tomographic examination showed a giant hepatic mass of left lobe origin, which was excised surgically. The pathology result was reported as a PEComa.

DISCUSSION

The diagnostic approach, treatment modalities, and follow-up procedures are not standard. The main treatment modality for PEComa is surgical excision with adequate surgical margin.

CONCLUSION

A longer follow-up is required for patients with hepatic PEComa because the nature of the disease is not entirely clear.

Hepatic angiomyolipoma: mutation analysis and immunohistochemical pitfalls in diagnosis

AIMS

Hepatic angiomyolipoma (AML) often shows epithelioid morphology with inconspicuous fat. Epithelioid component can mimic hepatocellular adenoma (HCA) or carcinoma (HCC). The aims of this study were to examine the expression of commonly used markers for HCA or HCC in hepatic AML and highlight pitfalls in diagnosis.

METHODS AND RESULTS

Resected hepatic AMLs (n = 16) were reviewed; reticulin stain, immunohistochemistry for glutamine synthetase (GS), β-catenin and liver fatty acid binding protein (LFABP) were performed along with Sanger sequencing of exon 3 of CTNNB1 and next-generation sequencing (NGS). Predominant epithelioid component (≥50%) was seen in 80% of cases. Foamy macrophage was present in 33% of cases. High-risk histological features were often present in tumours with benign outcome: marked atypia (19%), mitoses (20%) and necrosis (33%). GS staining (≥10% of tumour) was seen in epithelioid components in 13 (87%) cases, and was diffuse (>50% of tumour) in six (40%) cases. LFABP staining or nuclear β-catenin staining was not seen in any case. Sanger sequencing and NGS did not reveal CTNNB1 mutation in any tested case. NGS demonstrated TSC2 mutations in all five cases tested.

CONCLUSIONS

The predominance of epithelioid component resembling HCA or HCC is common in hepatic AML. Absence of LFABP and presence of fat can be mistaken for HNF1α-inactivated HCA. Diffuse GS staining can be mistaken for β-catenin-activated HCA or HCC. Diffuse GS expression is not related to CTNNB1 mutation. All tested cases showed TSC2 mutation, supporting this as the driving genetic event for hepatic AML.

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.

Hepatic perivascular epithelioid cell neoplasm: A clinical and pathological experience in diagnosis and treatment

Hepatic perivascular epithelioid cell neoplasm (PEComa) is a rare type of neoplasm derived from mesenchymal tumors that is often misdiagnosed as hepatocellular carcinoma (HCC), hepatic hemangioma or other liver malignancies. The clinical and histological characteristics of PEComa have yet to be fully documented. To optimize the diagnosis and treatment of the disease, a retrospective analysis was performed to investigate the clinicopathological characteristics of 7 patients diagnosed with hepatic PEComa in the Sun Yat-Sen Memorial Hospital between January 2004 and December 2015. Briefly, all the patients lacked specific symptoms, and a serological examination provided no further useful information. Additionally, non-specific imaging manifestations were observed. Microscopically, detection of epithelioid or spindle-shaped cells with adipocytes was suggestive of the disease, and an analysis of biomarkers, including the monoclonal antibody HMB-45, the melanocytic differentiation marker, Melan-A, and smooth muscle α-actin (SMA), helped to confirm the diagnosis. Regarding the treatment, 6 patients (85.7%) received surgical resection procedures, and 1 patient (14.3%) was admitted for tumor arterial embolization and percutaneous microwave coagulation therapy. After a follow-up period of 12–20 months, no recurrence was observed. Taken together, hepatic PEComa should be suspended in patients with a liver tumor with asymptomatic manifestation and normal serological test results. In imaging studies, hepatic PEComa was able to mimic HCC, hepatic hemangioma and metastatic tumor, although the mass did not invade the adjacent organs and vessel. The definitive diagnosis was made on the basis of the typical morphological features and notable markers of the tumor tissue. It is recommended that patients with PEComa in a benign pattern deserve serial imaging follow-up, but surgery is indicated in patients suffering from large tumors (>5 cm), or progressive enlargement or malignant tendency.

Hepatic perivascular epithelioid cell tumor in three patients

Perivascular epithelioid cell tumor (PEComa) is a rare, soft tissue tumor that can occur in various locations. The present report included three patients (one male and two females; age range, 25-51 years) with hepatic PEComas. The collected data included the clinical manifestations, diagnosis, management, treatment, and prognosis. Since it is difficult to diagnose hepatic PEComas by imaging, the patients were diagnosed by tumor tissue examination such as immunohistochemistry, which was positive for HMB-45, Melan-A, and SMA on all slides. The tumor was composed of diverse tissues including smooth muscle, adipose tissue, and thick-walled blood vessels. During the follow-up period, one of the tumors was malignant (double-positive for CD34 and Ki-67) and recurred 3 months after surgery. In addition, malignant hepatic PEComas were reviewed in the literature, indicating that the majority of hepatic PEComas are benign, but few hepatic PEComas exhibit malignant behaviors in older female patients (>50 years of age) with abdominal discomfort and pain, larger tumor size (>10 cm), or positive staining for CD34 and Ki-67. In conclusion, there is no effective method to diagnose PEComas. Currently, the diagnosis of PEComas depends on immunohistochemical staining. Tumor resection and close follow-up are the principal methods for the management of PEComas.

Hepatic angiomyolipomas: ultrasonic characteristics of 25 patients from a single center

Twenty-five pathologically proven hepatic angiomyolipomas (AMLs) were included in the study. Ultrasonic features of hepatic AMLs were reviewed. Three types of echogenicity were observed on ultrasound examination: (i) strong hyper-echogenicity, (ii) moderate hyper-echogenicity and (iii) hypo-echogenicity. Vascular signals within tumors could be detected in 22 (88.00%) tumors as multiple punctiform, filiform or dendriform signals by color Doppler flow imaging. Based on the enhancement patterns in the arterial, portal and late phases, the features of hepatic AMLs on contrast-enhanced ultrasound were divided into four subtypes: (i) "fast in slow out" (68.00%, n = 17); (ii) "fast in same out" (16%, n = 4); (iii) "fast in fast out" (12.00%, n = 3); and (iv) "fast in uneven out" (4.00%, n = 1). Contrast-enhanced ultrasound diagnosed 22 (88.00%) tumors as benign tumors and 13 (52.00%) as hepatic AMLs. Four cases were misdiagnosed as hepatic hemangioma, five cases as focal nodular hyperplasia (total = 36.00%). The rate of correct diagnosis of hepatic AMLs increased significantly from 24.00% for ultrasound alone to 52.00% for contrast-enhanced ultrasound. Therefore, information obtained from ultrasound, color Doppler flow imaging and contrast-enhanced ultrasound should be combined to improve diagnosis.

Immunohistochemical character of hepatic angiomyolipoma: for its management

Hepatic angiomyolipoma (AML) is notoriously difficult to diagnose without an invasive surgery even with the recent development of the various imaging modalities. Additionally, recent reports showed its malignant behavior after the surgery; it is important to diagnose the character of each tumor including the possible malignant potential and determine the postoperative management for each case. For this purpose, we have reviewed reports and focused on the immunohistochemical staining with p53 and ki67 of the tumors showing the representative case of 60-year-old female. The imaging study of her tumor showed the character similar to the hepatocellular carcinoma, and she underwent the hepatectomy. The resected tumor stained positive for HMB-45 that is a marker of the AML, and 30–50% of the tumor cells were positively stained with Ki67 that is a mitotic marker. Also, the atypical epithelioid cells displayed p53 immunoreactivity. These results suggest the malignant potential of our tumor based on the previous reports; therefore the careful followup for this case is necessary for a long period whether it shows metastasis, sizing up, and so forth.

Hepatic angiomyolipoma: diagnostic findings and management

Angiomyolipoma (AML) is a benign mesenchymal tumor that is frequently found in the kidney and, rarely, in the liver. The natural history of hepatic AML has not been clarified, and, because of the similar patterns in imaging studies, such as ultrasonography, computed tomography, and magnetic resonance imaging, some of these tumors have been overdiagnosed as hepatocellular carcinoma in the past. With an increase in the number of case reports showing detailed imaging studies and immunohistochemical staining of the tumor with human melanoma black-45, the diagnostic accuracy is also increasing. In this paper, we focused on the role of noninvasive imaging studies and histological diagnosis showing distinctive characteristics of this tumor. In addition, because several reports have described tumor progression in terms of size, recurrence after surgical resection, metastasis to other organs, and portal thrombosis, we summarized these cases for the management and discussed the indications for the surgical treatment of this tumor.