Malignant hepatic perivascular epithelioid cell tumor (PEComa) - Case report and a brief review

Primary Liver Perivascular Epithelioid Cell Tumor (PEComa): Case Report and Literature Review

A primary liver perivascular epithelioid cell tumor (PEComa) is an extremely rare entity. In this article, we present a case report with a review of the literature on the patients diagnosed with primary liver PEComa and an elaboration of diagnostic and treatment modalities. A systematic literature search was conducted using the terms "perivascular epithelioid cell tumor", "PEComa", "liver", and "hepatic". All articles describing patients diagnosed with primary liver PEComa were included. We identified a total of 224 patients of primary liver PEComa from 75 articles and a case from the present study with a significant preponderance of females (ratio 4:1) and with a mean age of 45.3 ± 12.1 years. Most of the patients (114 out of 224, 50.9%) were asymptomatic. A total of 183 (81.3%) patients underwent surgical hepatic resection at the time of diagnosis, while 19 (8.4%) underwent surveillance. Recurrence and metastases were detected in seven (3.1%) and six (2.7%) patients, respectively. In conclusion, surgical resection remains the cornerstone of therapy; however, the presence of nonspecific imaging features makes it difficult to reach a definite diagnosis preoperatively. Therefore, a multidisciplinary approach should be the gold standard in selecting the treatment modality.

Hepatic perivascular epithelioid cell tumor resembling hepatic adenoma and hepatocellular carcinoma on preoperative imaging: a case report

Perivascular epithelioid cell tumor (PEComa), an uncommon mesenchymal neoplasm, arises from specialized perivascular epithelioid cells exhibiting distinct features of smooth muscle and melanocytic differentiation with unpredictable behavior. PEComa tends to occur more commonly in the uterus and kidneys; its occurrence in the liver is exceedingly rare. We presented a case of a 29-year-old woman with hepatic PEComa and evaluated the tumor with MRI, integrated 18F-fluorodeoxyglucose (FDG), and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT scans at presentation. The patient had a history of intermittent utilization of oral contraceptive drugs for several years. An abdominal ultrasound in a physical examination from an outside institution revealed a mass in the liver. A contrast-enhanced abdominal MRI revealed restricted diffusion on diffusion-weighted imaging (DWI) and rapid contrast enhancement and washout patterns in the hepatic lesion, suggesting hepatic adenoma (HA) or hepatocellular carcinoma (HCC). Further assessment was carried out using 18F-FDG and 68Ga-FAPI PET/CT scans. The hepatic lesion was non-FDG avid, whereas increased tracer uptake was observed on the 68Ga-FAPI PET/CT. Subsequently, laparoscopic partial resection of liver segment V was performed. Immunohistochemical analyses demonstrated positive staining for HMB45, Melan-A, and SMA while showing negative results for AFP, glypican-3, hepatocyte, and arginase-1. The results were indicative of a hepatic PEComa diagnosis based on these findings. We also review the current literature on the clinical characteristics, pathological features, and challenges in the diagnosis of hepatic PEComa.

Very Rare Liver Tumor: PEComa Case Report with and a Review of Literature

Perivascular epithelioid cell tumors (PEComas) are very rare mesenchymal tumors. In addition to being rare in general, they are even rarer in the liver. There are various subtypes and there is only one case of liver PEComa reported in the clear cell type in the literature to date. We present the second clear cell type liver PEComa in this case by reviewing the literature data. The hypodense, smooth-edged, ovoid lesion was detected on computed tomography (CT) for performing abdominal pain in a 41-year-old female patient. Magnetic resonance imaging (MRI) was then performed for lesion characterization. The lesion was hypointense on T1-weighted imaging (T1WI), hyperintense on T2-weighted imaging (T2WI). In dynamic phases, it showed marked enhancement on the arterial phase and capsular enhancement with central washout on the portal and late venous phases. The posterior branch of the right portal vein extended into the mass. The lesion was excised and the pathological result was epithelioid clear cell subtype of PEComa. Although the imaging findings are generally nonspecific and certain diagnosis is made histopathologically, radiologists should consider PEComa in the differential diagnosis in the presence of intensely enhanced lesion on the right lobe in female patients. Also, the "large vessel sign" may help in the diagnosis.

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.

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

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

Hepatic perivascular epithelioid cell tumor: Clinicopathological analysis of 26 cases with emphasis on disease management and prognosis

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is an uncommon tumor of mesenchymal origin. Cases of PEComa in the liver are extremely rare.

AIM

To analyze the clinicopathological features and treatment of hepatic PEComa and to evaluate the prognosis after different treatments.

METHODS

Clinical and pathological data of 26 patients with hepatic PEComa were collected. All cases were analyzed by immunohistochemistry and clinical follow-up.

RESULTS

This study included 17 females and 9 males, with a median age of 50 years. Lesions were located in the left hepatic lobe in 13 cases, in the right lobe in 11, and in the caudate lobe in 2. The median tumor diameter was 6.5 cm. Light microscopy revealed that the tumor cells were mainly composed of epithelioid cells. The cytoplasm contained heterogeneous eosinophilic granules. There were thick-walled blood vessels, around which tumor cells were radially arranged. Immunohistochemical analysis of pigment-derived and myogenic markers in PEComas revealed that 25 cases were HMB45 (+), 23 were Melan-A (+), and 22 SMA (+). TFE3 and Desmin were negative in all cases. All the fluorescence in situ hybridization samples were negative for TFE3 gene break-apart probe. Tumor tissues were collected by extended hepatic lobe resection or simple hepatic tumor resection as the main treatments. Median follow-up was 62.5 mo. None of the patients had metastasis or recurrence, and there were no deaths due to the disease.

CONCLUSION

Hepatic PEComa highly expresses melanin and smooth muscle markers, and generally exhibits an inert biological behavior. The prognosis after extended hepatic lobe resection and simple hepatic tumor resection is semblable.

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.

PEComa-A Rare Liver Tumor

PEComa (perivascular epithelioid cell tumor) is a rare liver tumor. Decisions regarding patient management are currently based on a few small case series. The aim of this study was to report the clinicopathological features of PEComa in order to provide guidance for management, complemented by our own experience. This retrospective observational study included all patients with PEComa who underwent surgical treatment in two departments between 2002 and 2020. A total of 20 patients were diagnosed with PEComa following histopathological examination. The age of the patients ranged from 21 to 73 years. The majority of patients were women (85%). In most patients, the tumors were incidental. In diagnostic studies, PEComas with high arterial vascularization have been described. Liver resection was the treatment of choice. There was only one postoperative complication. During histopathological evaluation, tumors were composed mostly of epithelioid cells, rarely with spindle cell components, thick-walled vessels, and adipocytes in different proportions. Melanocytic markers (HMB45, MelanA) and at least one smooth muscle marker were expressed in all tumors. Features suggestive of malignancy were found in three cases. In conclusion, PEComa is a rare liver tumor that is usually diagnosed incidentally. In radiological studies, tumors with high arterial vascularization are observed. Liver resection is the treatment of choice.

[Hepatic epithelioid angiomyolipoma/PEComa and focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma]

Hepatic perivascular epithelioid cell tumors (PEComas) are uncommon mesenchymal neoplasms. PEComas concurrent with other hepatic lesions is a very rare occurrence, with only two previously reported cases. We report a primary hepatic PEComa associated with focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma. Diagnostic imaging studies suggested a hepatic adenoma and the patient underwent a segmentectomy. The tumor was mainly composed of epithelioid cells, adipose tissue and smooth muscle fibers intermixed with blood vessels. The neoplastic cells were diffusely immunoreactive for HMB-45, Melan-A and smooth muscle actin, but not for Hepatocyte, S100, MITF or BRAF. Molecular studies were negative for BRAFV600 mutation. The final diagnosis was hepatic epithelioid angiomyolipoma/PEComa. The differential diagnosis of hepatic PEComa is discussed.

Primary hepatic perivascular epithelioid cell tumors: imaging findings with histopathological correlation

Background

Hepatic PEComas are very rare. Few systematic reports are available characterizing the imaging and pathological features of hepatic PEComa. The aim of this study was to investigate the imaging findings of primary hepatic perivascular epithelioid cell tumors (PEComa) and its correlation with histopathological features.

Methods

The CT, MRI and ultrasound images and pathological findings of 22 patients with primary hepatic PEComa were retrospectively reviewed.

Results

More females (14/22) were affected with the mean age of 47.1 years. Most patients (17/22) were asymptomatic and the routine laboratory tests were normal. More tumors occurred in the right lobe (13/22) with a mean diameter of 76.7 mm. Surgery was performed in 21 patients, and biopsy was performed in 1 patient. Immunohistochemical studies showed the expression rate of HMB-45 and Melan A was 100% (22/22) and 86.4% (19/22) within the tumor cells. The pathology diagnoses were angiomyolipoma (n = 18), lymphangioleiomyoma (n = 2), clear-cell myomelanocytic tumor of falciform ligament/ligamentum teres (n = 1), and not otherwise specified (n = 1). Fifteen cases were classified as uncertain malignant potential (n = 13) or malignant (n = 2). CT, MRI and ultrasound features included well-defined margins (19/22), internal heterogeneity (20/22), arterial enhancement (20/22), dysmorphic vessels (17/22), fat (9/22), hemorrhage (3/22), necrosis (8/22), and calcification (2/22). The diagnostic accuracy was only 27.3% (6/22). No local recurrence or metastasis was found in the follow-up patients (12/22).

Conclusions

On CT, MRI and ultrasound images, most hepatic PEComas are well-defined, heterogeneous, arterial enhanced masses with dysmorphic vessels, with or without fat, especially in middle-aged females. With the potential to be malignant, timely surgical resection and long-term follow-up may be helpful for improving the prognosis.

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.

Computed tomography imaging features of hepatic perivascular epithelioid cell tumor: A case report and literature review

RATIONALE

Perivascular epithelioid cell tumor (PEComa) is a rare tumor which is most frequently found in uterus. The tumor arising from liver is extremely uncommon.

PATIENT CONCERNS

A 36-year-old female with abdominal distention, cramps, and low-grade fever for over 15 days. The patient had a history of gastric adenocarcinoma with ovarian, celiac lymph nodes, and retroperitoneal lymph nodes metastases.

DIAGNOSES

Computed tomography (CT) imaging demonstrated an ill-defined heterogeneous hypo-dense mass in segment 8 (S8) of the liver. Contrast-enhanced CT imaging showed marked enhancement in arterial phase, mild-to-moderate enhancement in portal and equilibrium phases. Tumor-feeding artery was demonstrated from the right hepatic artery by the three-dimensional reconstruction images. Biopsy was performed, and a diagnosis of PEComa was rendered.

INTERVENTIONS

No intervention for this tumor before liver biopsy.

LESSONS

We present a rare case of hepatic PEComa. The information we provided is useful for summarizing the CT features of this kind of tumors. It should be included in differential diagnoses from common hypervascular neoplasms of liver. The final diagnosis is established on histopathological and immunohistochemical studies that are the "gold standard."

Primary Hepatic Neoplasms of Vascular Origin: Key Imaging Features and Differential Diagnoses With Radiology-Pathology Correlation

OBJECTIVE

This article describes, illustrates, and correlates imaging and pathologic features of primary vascular mesenchymal neoplasms of the liver, which arise from the vascular endothelium and perivascular epithelioid cells.

CONCLUSION

Familiarity with the spectrum of benign, malignant-potential and malignant vascular neoplasms, and nonneoplastic mimickers allows consideration in the differential diagnosis of enhancing hepatic masses. Understanding relevant pathologic features facilitates recognition of key imaging features, specifically dynamic contrast enhancement patterns on CT and MRI, which provide a useful classification system.

Liver Perivascular Epithelioid Cell Tumor with an Unusual Location: Diagnostic Characteristics with Multidetector Computed Tomography and Magnetic Resonance Imaging

Primary perivascular epithelioid cell tumor (PEComa) of the liver is a very rare tumor that originates from mesenchyma. Gastrointestinal tract with perivascular distribution is the most common anatomic sites of these tumors. Only few cases of hepatic PEComa have been described so far. Malignant PEComas exhibit aggressive behavior with poor prognosis, making early diagnosis crucial. Hereby, we report a 79-year-old female with unusually located mass in the liver. A partial curative hepatectomy has been done, and PEComa was diagnosed histopathologically. No evidence of recurrence was observed during the 6-month follow-up.

Hepatic perivascular epithelioid cell tumor: Case report and brief literature review

RATIONAL

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm which expresses both myogenic and melanocytic markers. PEComas are found in a variety locations in the body, but up to now only approximately 30 cases about hepatic perivascular epithelioid cell tumor are reported in English language worldwide.

PATIENT CONCERNS

A 32-year-old woman was admitted in our hospital with intermittent right upper quadrant pain for 1 month and recent (1 day) progressive deterioration.

DIAGNOSES

Based on the results of the laboratory examinations and the findings of the computed tomography, the diagnosis of hepatic hamartoma or the hepatocecullar carcinoma with hemorrhage was made.

INTERVENTIONS

The patient underwent a segmentectomy of the liver, and the finally diagnosis of hepatic PEComa was made with immunohistochemical confirmation with HMB-45 and SMA.

OUTCOMES

There is no clinical or radiographic evidence of recurrence 9 months after surgery.

LESSONS

This kind of tumor is extremely rare and the natural history of PEComa is uncertain, as the treatment protocol for hepatic PEComa has not reached a consensus. But the main treatment of the disease may be surgical resection. Only after long term follow-up can we know whether the tumor is benign or malignant. It appears that longer clinical follow-up is necessary in all patients with hepatic PEComas.

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 epithelioid angiomyolipoma: clinical features and imaging findings of contrast-enhanced ultrasound and CT

AIM

To evaluate the clinical features and imaging findings of epithelioid angiomyolipoma (EAML) on contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT).

MATERIALS AND METHODS

During January 2006 to November 2015, six patients with histopathologically proven hepatic EAML were evaluated using both CECT and ultrasonography. Six patients underwent CEUS and four patients had CECT images. Patients' demographics, clinical presentations, laboratory test results, and imaging appearances were collected and analysed.

RESULTS

Six patients were female, and the mean age was 43.5 years. All hepatic EAMLs were solitary. None of patients had specific symptoms, and laboratory tests were normal in all patients. The maximal diameter of the lesions ranged from 3.1 to 6.5 cm (mean 4.4 cm). Baseline ultrasound revealed that 50% of hepatic EAMLs were hypo-echoic and 50% were mixed echoic. CEUS showed that 100% of the hepatic EAMLs displayed homogeneous hyperenhancement in the arterial phase and 67% (4/6) showed hypo-enhancement in the late phase. On CECT, 100% (4/4) of the neoplasms were significantly hyperenhanced in the arterial phase and washout in the portal phase. There was no recurrence or metastasis after a mean follow-up period of 11.8 months.

CONCLUSION

Hepatic EAML shows similar enhancement patterns to that of hepatocellular carcinoma. It should be considered as a possible differential diagnosis in female patients without viral hepatitis infection.