Immunohistochemical Study of Differential Expressions of CD31, ERG, VEGF-A, α-SMA, Glut-1, CD105, D2-40 and Ki-67 in Oral Intravascular Papillary Endothelial Hyperplasia

Abstract

Intravascular papillary endothelial hyperplasia (IPEH) is a benign non-neoplastic lesion histopathologically characterized by papillary proliferation of endothelial cells in dilated vascular lumen, and occurrence in the oral region is relatively rare. In this study, we performed clinical, histopathological, and immunohistochemical evaluations in 13 cases of oral IPEH, and examined the pathogenetic mechanism, pathophysiology, and differentiation from other vascular anomalies. The upper lip was the most common lesion site (5 cases), followed by the lower lip (3 cases) and the tongue (2 cases). The most common clinical diagnosis was hemangioma in 7 cases, followed by benign tumor in 4 cases. On gross examination, the tumor was dark red or mucosal color, similar to a hemangioma, and the surface was smooth, elastic and soft. Histological classification was mixed form in 11 cases and pure form in 2 cases. In immunohistochemical staining, CD31 was expressed in the cytoplasm and on cell membrane of vascular endothelial cells in all 13 cases; ERG was expressed in the nuclei of vascular endothelial cells in all 13 cases; α-SMA was expressed on cell membrane of smooth muscle cells in the blood vessel wall in all 13 cases; CD105 was expressed in the cytoplasm of vascular endothelial cells in 10 of 13 cases; and VEGF-A was expressed in the cytoplasm of vascular endothelial cells in all 13 cases. D2-40 was expressed in the cytoplasm and on cell membrane of endothelial cells within the papillary structures in only 2 cases, but Glut-1 expression was not detected in any of the cases. IPEH was easily differentiated from angiosarcoma, Kaposi's sarcoma, mucous cyst, and pyogenic granuloma. The pathogenetic mechanism of this disease suggested by this study is that thrombus formation induces a hypoxia and low glucose state at the lesion site, and VEGF produced by endothelial cells stimulates reactive proliferation of the endothelial cells to form IPEH.