Primary epithelioid hemangioendothelioma of the retroperitoneum: report of a case.

We herein report the case of a 48-year-old Japanese female with retroperitoneal epithelioid hemangioendothelioma (EHE), a rare malignant vascular tumor of intermediate grade. She was referred to our hospital because a retroperitoneal tumor was found during a medical checkup, in which strong accumulation of (18)F-fluorodeoxyglucose (FDG) was observed by (18)F-FDG-positron emission tomography (PET). A histological examination of the resected tumor revealed that it consisted of large epithelioid cells with vesicular nuclei, and clear cells with vacuolated cytoplasm and intracytoplasmic lumina. These cells expressed CD31 and vimentin, and the final pathological diagnosis was EHE. Postoperative surveillance with FDG-PET revealed distant metastasis in Virchow's lymph node 7 months after the operation. After dissection of the metastatic lymph node, the patient has been free from recurrence for 13 months. Close follow-up with FDG-PET seemed to be useful for surveillance of the recurrence of this tumor with unpredictable behavior, making an early treatment for the recurrent lesions possible.