ORBITAL HEMANGIOPERICYTOMA - CLINICAL AND MORPHOLOGIC FEATURES

PURPOSE: To report the clinical and histopathologic features of orbita l hemangiopericytoma. METHOD: We review the clinical and histopatholog ic features in seven patients.RESULTS: Ultrasonography, computed tomog raphy, and magnetic resonance imaging defined the location and extent of the tumor in each patient but did not disclose pathognomonic featur es for the specific diagnosis of hemangiopericytoma. The predominating histopathologic feature of each tumor was a mixed pattern of ovoid ce lls and sinusoidal space formations. Five patients showed mild to seve re cellular atypia; three had obvious pleomorphism and increased numbe r of abnormal mitotic figures. Tumor cells disclosed cytoplasmic react ivity for vimentin but in five cases were negative for other immunolog ic markers, Six patients received surgical treatment with an attempt f or total removal of the tumor; one had biopsy and radiation therapy. T n two patients, radiation therapy was given in addition to tumor remov al with orbital exenterations. Three patients died with recurrent and metastatic disease, and four patients are alive without tumor for a fo llow-up period ranging from 3 to 9 years. CONCLUSIONS: Orbital hemangi opericytoma may behave as a malignant tumor, leading to local recurren ce or metastasis, or both. Clinical and histopathologic findings shoul d be considered jointly to evaluate the clinical course; histopatholog ic findings alone are not sufficient to predict the biologic behavior of this tumor.