Masson tumor as humeral artery aneurysm.

Intravascular papillary endothelial hyperplasia (Masson's vegetant hemangioendothelioma) is a rare condition affecting the arteries. In the literature, we did not find any reference to this lesion involving the humeral artery. We present a case of asymptomatic humeral artery vascular tumor due to this abnormality. A 58-year-old woman was admitted to our hospital with an asymptomatic pulsatile humeral artery mass. Echography revealed an increase in size in the last year. The tumor was removed, and the vascular segment was replaced by a segment of inverted cephalic vein. The findings of the pathological examination were compatible with intravascular papillary endothelial hyperplasia. At follow-up examination 5 months after the operation, the patient had no tumor, remained asymptomatic, and had preserved upper limb artery patency. This rare vascular lesion may be clinically and histopathologically mistaken for a malignant tumor. As the Masson tumor can be cured by complete surgical resection, it is important to get a correct diagnosis.