Un hémangiome intraosseux localement agressif de siège inhabituel

Bone hemangioma is a benign primitive lesion characterized by the neoformation and the agglomeration of abnormal blood vessels. It most commonly involves the vertebrae and the craniofacial skeleton, but all of the bones may be injured. Astragalus involvement is rare. We here report the case of a 71-year old female patient with no particular past medical history, presenting with ankle pain evolving for two years. CT scan of the foot showed lytic lesion and associated fracture of the astragalus as well as a loss of substance inside the bone. Excisional biopsy was performed. Macroscopically this was a haemorrhagic friable material. Histologically, this was a benign vascular proliferation, consisting of vascular cavities, more or less filled with red blood cells and coated by a layer of flattened endothelial cells. There was no cytonuclear atypia or abnormal mitotic activity at the level of the endothelial cells. Immunohistochemically, these cells expressed the CD34. The diagnosis of bone hemangioma was made. Clinical and imaging manifestations of locally aggressive hemangiomas may be mistaken for a vascular or non-vascular malignant process. Histological examination is used to confirm the diagnosis. This tumor is generally stable, it sometimes regresses spontaneously in a few years. However, it may also have a locally aggressive evolution.