Wu Ji-Hua, Zhou Jin-Lian, Cui Yan, Jing Qing-Ping, Shang Le, Zhang Jian-Zhong
Department of Pathology and Experimental Medicine, 306 Hospital of PLA Beijing 100101, China.
Int J Clin Exp Pathol. 2013 Sep 15;6(10):2251-6. eCollection 2013.
Perivascular epithelioid cell tumors (PEComas) are a rare type of mesenchymal neoplasms characterized by a proliferation of perivascular cells with an epithelioid phenotype and expression of myo-melanocytic markers. The majority of PEComas seem to be benign and usually their prognosis is good. Malignant cases are extremely rare, exhibiting a malignant course with local recurrences and distant metastases. We herein report a case of a malignant PEComa arising in the retroperitoneum. The patient was a 55-year-old woman experiencing abdominal discomfort for approximately one month. Ultrasound and computer tomography (CT) scans of the abdomen revealed a solid mass arising from the retroperitoneum. Microscopically, the tumor was composed of epithelioid cells mixed with spindled cells. The nucleus had significant atypia, and the mitoses were obvious. The focal intravascular tumor embolus was visible. Immunohistochemically, the epithelioid tumor cells were positive for HMB45 and Melan-A, and the spindled tumor celLs were positive for SMA and desmin. Seven months after a surgical resection, an ultrasound revealed liver metastases. In conclusion, the malignant PEComas of the retroperitoneum is a very rare neoplasm with unique morphological and immunohistochemical characteristics. It should be differentiated from other epithelioid cell tumors of the retroperitoneum.
血管周上皮样细胞肿瘤（PEComas）是一种罕见的间叶性肿瘤，其特征为具有上皮样表型的血管周细胞增殖，并表达肌黑色素细胞标志物。大多数PEComas似乎是良性的，通常预后良好。恶性病例极为罕见，表现为恶性病程，伴有局部复发和远处转移。我们在此报告一例发生于腹膜后的恶性PEComa病例。患者为一名55岁女性，腹部不适约1个月。腹部超声和计算机断层扫描（CT）显示腹膜后有一实性肿块。显微镜下，肿瘤由上皮样细胞和梭形细胞混合组成。细胞核有明显异型性，有丝分裂明显。可见局灶性血管内肿瘤栓子。免疫组化显示，上皮样肿瘤细胞HMB45和Melan - A呈阳性，梭形肿瘤细胞SMA和结蛋白呈阳性。手术切除7个月后，超声显示肝转移。总之，腹膜后的恶性PEComas是一种非常罕见的肿瘤，具有独特的形态学和免疫组化特征。它应与腹膜后的其他上皮样细胞肿瘤相鉴别。
