Intravascular Papillary Endothelial Hyperplasia (Masson's Tumor) of the Radial Artery: A Case Report.

Intravascular papillary endothelial hyperplasia (IPEH), often referred to as Masson's tumor, is a benign non-neoplastic vascular lesion of the skin and subcutaneous tissues. Although it is rare, knowledge of the existence of IPEH is important as it can mimic other benign and malignant tumors, most notably angiosarcoma. IPEH remains an incompletely understood entity; however, most consider it to be the result of reactive endothelial proliferation following thrombus formation within a vessel, vascular malformation, or adjacent to a vessel. In this article, we report a case of IPEH arising within an arteriovenous malformation of the radial artery and present accompanying multimodality imaging and pathology figures. We will also describe the clinical presentation, pathophysiology, histology, imaging features, and management of IPEH.