Intravascular papillary endothelial hyperplasia: Report of 4 cases with immunohistochemicalfindings

ABSTRACT

Intravascular papillary endothelial hyperplasia (IPEH) is a benign endothelial proliferation, usually intravascular,that may mimic angiosarcoma. In this report, four new cases of IPEH involving the oral region are described.The affected sites were the lower lip, labial comissure and the submandibular region. After clinical evaluation, thecomplete removal of the lesions showed a circumscribed and soft mass. Histologically, the major feature was areactive proliferation of endothelial cells composed of small papillary structures with hypocellular and hyalinizedcores arising in an organized thrombus. Immunohistochemical staining for CD34 was strongly positive in endothelialcells. Vimentin and laminin immunolabelling were also consistent with a vascular origin. In order to verifythe proliferative potential of the lesions, the Ki-67 antibody was used, revealing low percentage of labeled cells(<20%). No immunoreactivity for GLUT-1 was observed. Since the complete removal is curative, no additionaltreatment was necessary, and no signs of recurrence had been observed until now. Due to the particular features ofIPEH, it is important for pathologists and clinicians to become familiar with this lesion. Additionally, the specifichistological arrangement, including the absence of cellular pleomorphism, mitotic activity and necrosis, representsa guide to help in the differential diagnosis. Moreover, the vascular origin and the proliferative index should beassessed by immunohistochemistry in order to provide an accurate diagnosis (AU)