Epithelioid angiosarcoma of the orbit presenting as Tolosa-hunt syndrome: a clinicopathologic case report with review of the literature

The clinical diagnosis of Tolosa-Hunt syndrome was first considered in a 66-year-old man with facial pain and diplopia. A complete neuroradiologic evaluation as well as an oncologic work-up yielded normal results. Several courses of oral prednisone provided no significant benefit. Within a year the patient became clinically worse and a CT scan disclosed an abnormal area of enhancement at the left orbital apex. An orbital exploration was performed elsewhere and a histologic diagnosis of myositis was obtained. Because of further worsening the patient was re-evaluated 3 months later and a CT scan showed a mass in the left orbital apex and superior orbital fissure. A second orbital exploration was performed and a sausage-shaped mass encompassing the optic nerve was excised. By light microscopy a poorly differentiated malignant tumor was infiltrating the orbital tissues with areas of intra- and perineural invasion. The tumor cells were arranged in strands and tubules with a definite tendency to form lumens that often contained red blood cells. Electron microscopic studies disclosed features consistent with a neoplasm of endothelial cell origin displaying a polarized basal lamina and rare micropinocytotic vesicles on the luminal side. The presence of multiple, slender microvilli and sometimes tonofilaments as well as desmosomes were interpreted as epithelioid metaplasia of an angiosarcoma.