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Int J Clin Exp Pathol 2013;6(10):2251-2256

Case Report
Malignant perivascular epithelioid cell tumor of the retroperitoneum

Ji-Hua Wu, Jin-Lian Zhou, Yan Cui, Qing-Ping Jing, Le Shang Jian-Zhong Zhang

Department of Pathology and Experimental Medicine, Department of General Surgery, 306 Hospital of PLA, Beijing 100101, China

Received July 26, 2013; Accepted August 19, 2013; Epub September 15, 2013; Published October 1, 2013

Abstract: 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. (IJCEP1307046).

Keywords: Retroperitoneum, perivascular epithelioid cell tumors, clinicopathology

Address correspondence to: Dr. Jian-Zhong Zhang, Department of Pathology and Experimental Medicine, 306 Hospital of PLA, Beijing
100101, China. E-mail: zhangjz55@sina.com