Hepatic perivascular epithelioid cell tumor: A case report

Contrast-Enhanced Ultrasound of a Hepatic Perivascular Epithelioid Cell Tumor: A Case Report and Literature Review

Primary hepatic perivascular epithelioid cell tumor (PEComa) is an exceptionally rare mesenchymal neoplasm of borderline malignancy, with limited documentation of its contrast-enhanced ultrasound (CEUS) features in medical literature. In this context, we present a 53-year-old male patient without chronic liver disease, who exhibited a well-circumscribed hypoechoic left hepatic lobe mass on conventional ultrasonography. Subsequent CEUS demonstrated characteristics indicative of malignant tumors, with specific manifestations during the arterial phase, thereby informing clinical decision-making toward surgical resection. Histopathological confirmation of capsular-invasive PEComa underscores the utility of CEUS in characterizing such lesions, particularly in middle-aged patients with incidental solitary hepatic masses lacking predisposing risk factors. These findings advocate for the integration of CEUS into diagnostic algorithms to enhance specificity in atypical hepatic tumor evaluations.

A retrospective clinical analysis of 11 cases of PEComa from different sites

PURPOSE

The objective of this paper is to offer a thorough examination of the clinical presentations, etiology, and treatment strategies associated with perivascular epithelioid cell tumors (PEComas).

METHODS

This retrospective study examined the comprehensive archival data of PEComa cases diagnosed at Beijing Hospital from 2015 to 2023. The pathology slides of all patients were thoroughly reassessed by two experienced pathologists. A thorough retrospective analysis was undertaken, incorporating clinicopathological data including gender, age at diagnosis, initial clinical manifestations, signs, disease onset site, tumor markers, imaging findings, therapeutic modalities, pathological features, immunohistochemical profiles, treatment responses, and prognostic indicators. Patients were evaluated for disease severity according to established pathological classification criteria and were followed up until the designated analysis cut-off date. In instances where patients were unable to be monitored on-site, they were contacted via telephone for postoperative follow-up inquiries.

RESULTS

This study included 11 patients with ages ranging from 17 to 66 years old, presenting with the disease in multiple anatomical sites, including the retroperitoneum (2/11), liver (4/11), kidney (4/11), lung (1/11), and broad ligament of the uterus (1/11). Most patients presented with non-specific clinical symptoms and were subsequently diagnosed with space-occupying lesions upon physical examination. The tumor demonstrated progressive growth and enlargement, which could result in compression of neighboring organs. Preoperative imaging alone is insufficient for a definitive diagnosis of PEComa, but MRI can provide an initial evaluation of the tumor's potential malignancy. Molecular marker testing specific to PEComa, such as HMB-45 (90.0%), SMA (81.8%), Melan-A (90.9%), vimentin (90.9%), and Desmin (36.3%), was conducted on all patients. No adjuvant therapies were administered postoperatively. Upon analysis, no instances of relapse at the primary site or the development of new tumors at other sites were observed. Regular imaging reviews of three patients with malignant PEComa post-surgery showed no evidence of recurrence.

CONCLUSIONS

The clinical presentation, tumor biomarkers, and imaging characteristics of PEComa lack specificity, necessitating dependence on pathology and immunohistochemistry for precise diagnosis. The mainstay of treatment consists of surgical resection, with patients typically experiencing a favorable prognosis.

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 (PEComa): contrast-enhanced ultrasound (CEUS) characteristics-a case report and literature review

Perivascular epithelioid cell tumors (PEComa) are rare mesenchymal neoplasms that arise from soft tissue of various organs such as the stomach, intestines, and lungs. We report a rare case of a primary PEComa of the liver and its characteristics on contrast-enhanced ultrasound (CEUS) in a 51-year-old female patient with an incidental finding of a hypoechoic liver lesion with peripheral hypervascularization on Doppler ultrasound. CEUS showed homogenous hypervascularity in the arterial phase that was consistent in the portal phase. In the late phase, a central washout phenomenon was evident. Histopathologic findings on sonographic biopsy of the lesion revealed a mesenchymal tumor with positivity for melanocytic markers Human Melanin Black-45 (HMB45) and Melan-A consistent with a PEComa. Despite the absence of high-risk features for malignancy, surgical resection was recommended due to the uncertain malignant potential of PEComas. The patient refused the operation and preferred sonographic follow-up; the lesion was stable over a period of 2 years. CEUS can provide valuable information regarding PEComa. After histological confirmation, the choice between resection and a watchful waiting must be made on individual basis.

Sonazoid-enhanced ultrasonography and pathologic characters of CD68 positive cell in primary hepatic perivascular epithelioid cell tumors: A case report and literature review

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal tumor rarely described in the liver. Sonazoid is a new ultrasound contrast with both vascular and post-vascular phases due to the uptake of Kupffer cell. CD68 is a defined immunohistorical staining marker for macrophage including Kupffer cell. No previous cases have been reported to reveal Kupffer images in the post-vascular phase by using Sonazoid and pathologic characters of CD68 positive cell in PEComa. Herein, we describe the first case to present Sonazoid contrast-enhanced ultrasonography (CEUS) findings in Kupffer images and CD68 positive cell in hepatic PEComa which may lead to rethink of the phagocytic properties of macrophages.

Unusual Primary Neoplasms of the Adult Liver: Review of Imaging Appearances and Differential Diagnosis

The radiological appearance of common primary hepatic tumors such as hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) is widely recognized. Hepatic masses with unusual histology are occasionally encountered, but seldom suspected on imaging. However, many possess characteristic imaging findings, which when assessed along with the clinical and demographic background and serum tumor markers, may enable a prospective diagnosis. This review attempts to familiarize the reader with the clinicopathological characteristics, imaging manifestations, and differential diagnosis of these unusual liver tumors in adults. Biphenotypic primary liver carcinoma is suspected in masses showing distinct areas of HCC and CCA-type enhancement pattern in cirrhotic livers. Fibrolamellar carcinoma occurs in young individuals without underlying chronic liver disease and shows a characteristic T2-hypointense scar frequently showing calcification. Perivascular epithelioid cell tumors are differentials for any arterial hyperenhancing mass in the noncirrhotic liver, particularly in patients with tuberous sclerosis. Multifocal subcapsular tumors showing target-like morphology, capsular retraction and "lollipop" sign are suspicious for epithelioid hemangioendothelioma. On the other hand, multiple hemorrhagic lesions showing patchy areas of bizarre-shaped arterial phase hyperenhancement are suspicious for angiosarcoma. Primary hepatic lymphoma (PHL) is suspected when patients with immunosuppression present with solitary or multifocal masses that insinuate around vessels and bile ducts without causing luminal narrowing. Intense diffusion restriction and low-level homogeneous or target-like enhancement are also ancillary features of PHL. Primary hepatic neuroendocrine tumor shows uptake on Ga-68 DOTANOC PET/CT. Although a straightforward diagnosis may be difficult in these cases, awareness of the characteristic imaging appearances is helpful in suspecting the diagnosis.

Bladder PEComa: A case report and literature review

The location of PEComa is rare in bladder, and the misdiagnosis rate is very high before operation.the characteristic of the bladder PEComa is that the CT is a round, elliptical or irregular cystic mass with a large volume, more than 5 cm or more, and the edge is clear. The solid part of the scanning tumor is obviously enhanced, and the rich blood supply artery and the drainage vein can be seen.