EHE was first reported by Wesis and Enzinger in 1982[6], and HEHE was first discribed by Ishak in 1984 [7]. Epithelioid endothelial cell tumor is a rare malignant tumor originated in endothelial cells [1], can be in each part, with limb soft tissue for many, also seen in other organs such as lung, bone, spleen, brain[2]. HEHE etiology has not been clearly identified, the possible pathogenic factors include oral contraceptives, progesterone disorders, liver trauma, alcohol, vinyl chloride pollution, viral hepatitis, liver cirrhosis, liver transplantation, long-term use of immunosuppressive agents, etc. [1]. The commonality of some of the above factors is that they stimulate the proliferation of hepatic vascular endothelial cells at the molecular level [8]. No other special medical history was found in this patient, and no treatment factors related to this disease were found.
The onset of the disease is relatively insipid, and most of the cases have reached the middle and late stage when the disease is diagnosed. The common symptoms are epigastric discomfort or pain, fatigue, poor appetite and so on. Occasionally, fever and jaundice are seen. Although HEHE is a low-grade malignant tumor, metastasis occurs in 1/3 of the cases due to the rich blood sinus of the liver. Tumor cells are prone to invade the terminal branches of the portal vein, and migrate most commonly to the lung or the abdominal cavity. The patients with metastatic tumor can die from liver and respiratory failure. It is difficult to distinguish polycentric origin from metastasis because it can be transferred from primary organs to other tissues and organs, and also has multiple primary lesions at the same time [8].
Most HEHE lesions are multiple, and most of them are located under the liver capsule or around the liver. The imaging characteristics of HEHE mainly include: capsular retraction, calcifications, halo sign and target sign [4]. Most plain CT scans were of low density, and some lesions showed a circular shape with lower density. Enhanced CT scans showed progressive enhancement, which was related to the size of the lesions [9]. MRI showed a clearer tumor structure, and MRI plain scan showed hypointense on T1-weighted images and hyperintense on T2-weighted images. The larger lesion (> 2 cm) is prone to liquefaction necrosis, and the lesion density or signal is uneven [10].
The diagnosis of HEHE was mainly based on pathology. The gross appearance of HEHE was mostly nodules with infiltrating growth of grayish-white tough masses. Under the microscope, the tumor cells were mostly arranged in a dense and disordered pattern with a cord-like or nested cord-like distribution, and the cell morphology was mostly epithelioid, fusiform or irregular. Hypertrophy irregular nuclei, uneven chromatin or coarse granular; The cytoplasm is abundant and eosinophilic, and there are often vacuoles containing red blood cells in the cytoplasm. The stroma is rich in collagen and mucous or hyaline degeneration. The positive rates of CD34, CA31 and Vimentin were the highest [5].
Differential diagnosis: (1) Low differentiation adenocarcinoma: Due to the epithelioid morphology and intracytoplasmic vacuoles of EHE, it is easy to be misdiagnosed as adenocarcinoma, especially in a puncture specimen. The heterogeneity of adenocarcinoma cells is more obvious, and the two can be distinguished by using cytokeratin and vascular endothelial markers. (2) Epithelioid angiosarcoma: the cellular heterogeneity is significant, with more nuclear schwannosis and often associated with necrosis. A small number of patients with EHE have some overlap with epithelioid angiosarcoma, and it is presumed that the two have a continuous spectrum of morphology. A combination of immunohistochemical staining can clearly differentiate between the two.[11]
Currently, there is no standard treatment, including surgical resection, liver transplantation, and hepatic arterial chemoembolization. For HEHE detected at early stage, isolated or confined to hepatic segments or lobes, radical resection is the first choice, most of which can achieve a better prognosis, and the 5-year survival rate of patients with radical resection can reach 55% [12]. Liver transplantation is an ideal option for patients without radical resection. Lai[13] summarized 149 HEHE patients registered in the European liver transplantation registration system from November 1984 to May 2014, and found that the 1-year, 5-year and 10-year survival rates of HEHE patients after liver transplantation were 88.6%, 79.5% and 74.4%, and the 1-year, 5-year and 10-year disease-free survival rates were 88.7%, 79.4% and 72.8%, respectively. For HEHE patients without radical resection and without liver transplantation treatment, radiotherapy, chemotherapy and intervention therapy can be selected according to the situation.