Contrast-Enhanced Ultrasound Characteristics of Hepatic Perivascular Epithelioid Cell Tumor

To explore the contrast-enhanced ultrasound (CEUS) characteristics of hepatic perivascular epithelioid cell tumors (PEComas).

A retrospective analysis was conducted on eight patients with pathologically confirmed hepatic PEComas at Sun Yat-sen Memorial Hospital, Sun Yat-sen University, between November 2019 and October 2024. The CEUS characteristics of hepatic PEComas were summarized, and the correlation between pathological components and ultrasonographic manifestations was analyzed. A literature review was performed using PubMed to identify studies reporting CEUS features of hepatic PEComas.

The study cohort comprised six females and two males, with a mean age of 48.12 ± 16.47 years. On conventional ultrasound (CUS), lesions were either hyperechoic (4/8) or hypoechoic (4/8), with hyperechoic lesions exhibiting a higher mean fat content (27.5% vs. 15%). Lesions with peripheral annular flow demonstrated a slightly higher mean vascular density compared to those without (14.2% vs. 10%). All lesions (8/8) exhibited marked hyper-enhancement in the hepatic arterial phase (HAP), with a mean time-to-enhancement of 12.25 ± 4.06 s and a mean time-to-peak of 20.88 ± 3.91 s. In the portal venous phase (PVP), lesions showed iso-enhancement (6/8) or hypo-enhancement (2/8), while in the delayed phase (DP), they displayed iso-enhancement (5/8) or hypo-enhancement (3/8), consistent with a "fast-in and slow-out" (FISO) enhancement pattern. The literature review identified 10 studies (comprising 20 lesions) published between 2006 and March 2025, which described CEUS characteristics of hepatic PEComas that were consistent with those observed in our cohort.

Hepatic PEComa is a rare liver tumor often detected incidentally. It typically demonstrates marked homogeneous hyper-enhancement during the HAP, followed by a "FISO" enhancement pattern. Preoperative diagnosis and differentiation between benign and malignant forms of hepatic PEComa remain challenging using CUS. CEUS provides additional diagnostic characteristics for hepatic PEComas and holds value in the differential diagnosis of focal liver lesions.