Computed tomography imaging features of hepatic perivascular epithelioid cell tumor

Abstract

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.”

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

“…Thus, the expression of Melan-A, HMB45, and SMA are the most important evidence for hepatic PEComa. This result was consistent with other studies [1–31] . Surprisingly, these markers were not 100% positive in previously reported cases, and Folpe et al [30] found that only 80% of PEComas were simultaneously positive for melanocyte and smooth muscle cell markers.…”

“…According to the results of this study, hepatic PEComas were more likely to occur in the right lobe. However, combined with the findings from other studies, as the sample size increases, the number of tumours occurring in the left lobes was approximately equal to the right [1–19] …”

“…PEComas 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 [1–11] . 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] .…”

“…Many specific manifestations of hepatic PEComa are able to be observed using CT and MRI, which will help effectively improve the diagnostic accuracy. First, a circular or quasi-circular inhomogeneous occupancy with a low density, clear boundaries and expansive growth has been observed on a plain scan, and adipose tissue, haemorrhage, necrosis and cystic degeneration have occasionally been detected in the tumours [4] . Second, the lesions with the features of neovascularization and arteriovenous connections are heterogeneously enhanced obviously in the arterial phase, which is the most important condition for the diagnosis of a hepatic PEComa [19] .…”

“…The first is a special group containing four types: pulmonary clear cell “sugar” tumour, clear cell myomelanocytic tumour of the falciform ligament/round ligament, lymphangioleiomyomatosis, and angiomyolipoma (AML). The second is a non-special type called PEComa-not otherwise specified (PEComa-NOS) which can occur in the abdomen, pelvis, digestive tract and other tissues with a low incidence; thus, it has no formal name [4] …”