Primary Multifocal Hepatic PEComa: A Rarely Encountered Diagnostic Dilemma

Excerpt

The origin of perivascular epithelioid cell neoplasm (PEComa) family of tumors was first proposed by Bonetti et al. [1] in 1992, and in 2002 World Health Organization (WHO) defined PEComa as “mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells” [2]. In 2013, the WHO redefined them as mesenchymal tumors composed of distinctive cells that show a focal association with blood vessel walls and co-express melanocytic and smooth muscle markers [3]. This group of mesenchymal neoplasm includes angiomyolipoma (AML), clear cell sugar tumor (CCST) of the lung, lymphangioleiomyomatosis (LAM), and a variety of intraabdominal, visceral, and soft tissue tumors with similar immunophenotypical features [4]. Although PEComas show a wide anatomical distribution, most commonly they arise in the retroperitoneum, abdominopelvic region, uterus, and gastrointestinal tract. Hepatic PEComas are rare [4] with only a few cases of multifocal hepatic PEComas being described in the literature [5]. Especially multifocal hepatic PEComas pose clinical and radiological diagnostic dilemma and often mimic a metastatic carcinoma or multifocal hepatocellular carcinoma (HCC). Histopathological analysis can play an essential role in the diagnosis and characterization of such lesions with the aid of positive immunohistochemical staining [4]. They are though primarily benign tumors; they can rarely behave like a malignant lesion [6]. We are reporting a case of primary multifocal hepatic PEComa diagnosed clinically as HCC. …