Hepatic perivascular epithelioid cell tumor: Five case reports and literature review

Abstract

Perivascular epithelioid cell tumor (PEComa) is a rare tumor. Here, we present data regarding clinical presentations, diagnoses, management, and prognosis of five cases of hepatic PEComa between January 2002 and December 2008. Ultrasonography showed hyperechoic masses in all patients. Precontrast computed tomography (CT) showed that all lesions scanned were heterogeneous in density and were heterogeneously enhanced in arterial phase images. In two cases, magnetic resonance imaging showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images. In enhanced scanning, lesions showed asymmetrical enhancement during arterial phase imaging. All tumors were composed of varying proportions of smooth muscle, adipose tissue, and thick-walled blood vessels, and showed positive immunohistochemical staining for Human Melanoma Black-45. All patients underwent hepatectomy, and there was no evidence of recurrence or metastasis during the follow-up period.

New recognition of hepatic perivascular epithelioid cell tumours (PEComa): a retrospective analysis of 35 cases

“…A PEComa can occur in many parts of the human body, such as the uterus, skin, thorax, gastrointestinal tract and liver. The prognosis of benign hepatic PEComas, which are able to be radically cured by surgery, is usually satisfactory and little evidence of recurrence or metastasis of these tumours has been reported after surgery in previous case studies [1][2][3][4][5][6][7][8][9][10][11]. In contrast, malignant hepatic PEComas characterized by aggressive growth and early metastasis have a poor prognosis, but the incidence is much lower than benign hepatic PEComas [12].…”

“…In contrast, malignant hepatic PEComas characterized by aggressive growth and early metastasis have a poor prognosis, but the incidence is much lower than benign hepatic PEComas [12]. Studies have con rmed that 6-10% of cases of hepatic PEComa are associated with a genetic disease called TSC, because the pathogenesis of PEComa may be related to the deletion of TSC1 (9q34) or TSC2 (16p13.3) [2]. Shih-Chiang Huang et al [13], who had analysed specimens of hepatic PEComa, also found that hepatic PEComas are associated with an alteration in the mTOR pathway and a loss of heterozygosity (LOH) in the TSC1/TSC2 genes, particularly in TSC2.…”

“…Hepatic perivascular epithelioid cell tumours (PEComa) speci cally express markers of melanocytes and myocytes when examined using immunohistochemistry and are a type of rare neoplasm originating from mesenchymal tissues [1]. In 1996, Zamboni et al formally classi ed a group of related mesenchymal tumours as "PEComa", a term that was rst proposed by Bonetti in 1992 [2]. The World Health Organization (WHO) o cially described PEComas as "a kind of abnormal mesenchymal tumour consisting of perivascular epithelioid cells with unique histological and immunohistochemical features" [3].…”

“…Hepatic PEComas are benign tumours with some malignant biological behaviours. Although hepatic PEComas are extremely rare, the incidence has increased in recent years and some malignant biological behaviours are potential threats to people [2]. On the one hand, we have little knowledge of the clinical features, imaging ndings and pathological characteristics of hepatic PEComas.…”

Computerized Tomography and Magnetic Resonance Imaging Findings in Malignant Perivascular Epithelioid Cell Tumors of the Ovaries with Pulmonary Metastasis

“…This type of tumor consists of three components: thick-walled often hyalinized blood vessels, smooth muscle cells, and adipose tissue. Angiomyolipoma of the kidney and liver, clear cell “sugar” tumor of the lung, and lymphangiomyomatosis are all PEComas (7). There have been approximately 100 cases of PEComas previously reported in the literature, either as case reports or small sample studies.…”