Hepatic perivascular epithelioid cell neoplasm: A clinical and pathological experience in diagnosis and treatment

Abstract

Hepatic perivascular epithelioid cell neoplasm (PEComa) is a rare type of neoplasm derived from mesenchymal tumors that is often misdiagnosed as hepatocellular carcinoma (HCC), hepatic hemangioma or other liver malignancies. The clinical and histological characteristics of PEComa have yet to be fully documented. To optimize the diagnosis and treatment of the disease, a retrospective analysis was performed to investigate the clinicopathological characteristics of 7 patients diagnosed with hepatic PEComa in the Sun Yat-Sen Memorial Hospital between January 2004 and December 2015. Briefly, all the patients lacked specific symptoms, and a serological examination provided no further useful information. Additionally, non-specific imaging manifestations were observed. Microscopically, detection of epithelioid or spindle-shaped cells with adipocytes was suggestive of the disease, and an analysis of biomarkers, including the monoclonal antibody HMB-45, the melanocytic differentiation marker, Melan-A, and smooth muscle α-actin (SMA), helped to confirm the diagnosis. Regarding the treatment, 6 patients (85.7%) received surgical resection procedures, and 1 patient (14.3%) was admitted for tumor arterial embolization and percutaneous microwave coagulation therapy. After a follow-up period of 12–20 months, no recurrence was observed. Taken together, hepatic PEComa should be suspended in patients with a liver tumor with asymptomatic manifestation and normal serological test results. In imaging studies, hepatic PEComa was able to mimic HCC, hepatic hemangioma and metastatic tumor, although the mass did not invade the adjacent organs and vessel. The definitive diagnosis was made on the basis of the typical morphological features and notable markers of the tumor tissue. It is recommended that patients with PEComa in a benign pattern deserve serial imaging follow-up, but surgery is indicated in patients suffering from large tumors (>5 cm), or progressive enlargement or malignant tendency.

Computed tomography imaging features of hepatic perivascular epithelioid cell tumor

“…PEComas are neoplasms of mesenchymal origin, and relatively rarer, malignant variants even more so. [ 8 , 9 ] They have been documented in various anatomical sites, most frequently in the uterus whereas particularly uncommon in liver. [ 2 ] Almost all the PEComas were identified to be strongly positive for HMB-45, SAM, and Melan-A, which are helpful for confirming the diagnosis.…”

“…One lesion is unenhanced. [ 8 ] In our case, maximum intensity projection (MIP), curved planar reconstruction (CPR), and volume rendering technique (VRT) algorithm are created for three-dimensional (3D) reconstruction and it is able to precisely show the supplying vessel for the tumor. This is the first paper that demonstrates the characteristic of tumor-feeding artery.…”

Hepatic Angiomyolipoma

“…The reason was that AML contained different degrees of dilated and distorted vascular networks, and the contrast agent entered the rich vascular network, making the lesion substantially enhanced in the arterial phase. 23 In nonepithelial AML, in which fat cells are more common and deformed blood vessels are scattered and staggered, the amount of blood vessels is substantially lower than that of the epithelial type; blood flow is slow in vessels, and the contrast agent stays in blood vessels for a long time. The arteries of epithelial AML were rapid filled, and at the same time, the intracavitary pressure of the arterial vessels was increased.…”

Unresectable hepatic PEComa: a rare malignancy treated with stereotactic body radiation therapy (SBRT) followed by complete resection

“…They predominantly affect women and occur in nearly every organ [ 4 ]. The incidence of benign and malignant PEComa of the liver is much lower than for other locations [ 5 ].…”