[Retiform haemangioendothelioma: a case report].

Retiform haemangioendothelioma is a locally aggressive, very rarely metastasizing vascular lesion. Histologically, it is characterized by distinctive arborizing blood vessels resembling "rete testis" and lined by endothelial cells with characteristic hobnail morphology. We present an additional case, in the leg of a 64-year-old patient. We discuss the classification of hemangioendotheliomas. The term hemangioendothelioma should be restricted to vascular tumours of "intermediate malignancy" but has been used to designate tumours with variable histological features and clinical behaviour. Spindle cell hemangio(endothelio)ma is currently regarded as a benign reactive lesion. Kaposiform hemangioendothelioma is potentially lethal due to consumption coagulopathy but no metastasizing case has been reported. Epithelioid hemangioendothelioma is associated with a significant metastatic risk and has been included in the category of malignant vascular tumors. The vascular lesions fulfilling the strict definition of hemangioendothelioma include retiform hemangioendothelioma, papillary intralymphatic angioendothelioma "Dabska's tumor", composite hemangioendothelioma and perhaps the controversial polymorphic hemangioendothelioma.