In 1983 Hashimoto 6 classified IPEH into (1) pure, deriving from dilatation of the vessels of the head-neck region; (2) mixed, deriving from previous vascular lesions such as aneurysms, arteriovascular malformations, and chronic venous pathologies; (3) extravascular, originating from a hematoma caused by previous trauma. The present case, like the other 4 described in the literature, seems to belong to the first type. Intravascular papillary endothelial hyperplasia is more frequently found in the skin and subcutis, in fact diagnosing a Masson's tumor into the skeleton is very uncommon. The documented clinical cases occurred at the level of the skull, at the base of the skull, at the tibia, and on the fingers of the hand. 7 Komori et al 8 in 1984, described the first case of IPEH of the mandible, the patient did not report any symptoms and no mucosal lesions were evident. The second case concerned a lesion of the right mandibular branch was characterized by the presence of trismus and swelling with strong painful symptomatology. 7 Tanio et al, 2 reported a case localized in the anterior mandibular area, in which it presents a bone mass covered with healthy mucosa, also in this case the patient reported painful symptoms. The last case in literature describes the presence of a lesion of considerable size that caused an asymmetry of the face, with the involvement of the intraoral mucosa that was ulcerated, necrotic, and with areas of fungal infection. 3 In all the cases described above, the radiographic findings showed radiolucent multilocular areas, and, depending on the size, was possible to appreciate the involvement of the bone cortex.Considering the variability of the clinical manifestations and the symptomatology, it is fundamental to orientate correctly in the differential diagnosis. From radiographic images, it is necessary to carry out a differential diagnosis between osteolytic lesions with multilobulated appearances such as multicystic ameloblastoma, odontogenic keratocyst, and giant cell bone tumor and IPEH. 4,[9][10][11] Histologically, IPEH must be differentiated from malignant tumor such as angiosarcoma, malignant endovascular papilloma, due to their clinical and pathological similarities. 12 In particular, microscopically, IPEH presents itself as a vascular proliferation initially with coarse papillae with fibrin core, lined by of endothelial cells with plump appearance, in the late stage, fusing of the papillae give rise an anastomosing network of small vessel. At low-magnification, the lesion appears strongly confined to the lumen of a thrombus, in a fibrous pseudo-capsule, in an hematoma or in a large vessel. This feature is crucial for the differential diagnosis with angiosarcoma, because angiosarcomas are almost never confined to a vascular lumen. These findings alongside with the absence of nuclear atypia, cellular pleomorphism, atypical miosis, necrosis, and irregular vessels are also major features differentiating IPEH from angiosarcoma. 13,14 Surely bone surgery has made many steps forwa...