Immunohistogical study of benign oral vascular neoplasm and malformations

Objectives: Benign oral vascular neoplasm (BVN) and vascular malformations (VM) exhibit broad spectrum of clinical and histological characteristics and definitive differential diagnosis between these lesions is often difficult. This study was conducted to investigate the clinicopathological and immunohistochemical characteristics of BVN and VM. Materials and Methods: Eighty-three cases of BVN and VM of the oral cavity were subjected to histopathological and immunohistochemical studies using hematoxylin-eosin, Alcian blue, and monoclonal antibodies against vWF/FVIII Related antigen (vWF/FVIIIRag), CD31, CD34, VEGF, D2-40, Ki-67 and smooth-muscle actin (SMA). Mast cells were counted per 10 high power field (HPF) while immunoreactivity was evaluated at 200 X magnification. Results were organized into 4 categories as follows: (-) <10%, (+) = 10-30%, (++) = 30-60%, (+++) > 60%. Results: Mean age distribution was 45.70±19.66 years old and most were located at the lips, tongue, and buccal mucosa. Majority were acquired during the 5th to 7th decades of life and only a minority was noted at birth or early childhood. BVN has increased endothelial cell proliferation while VM has dilated vascular vessels lined by flat endothelial cells; however; plump endothelial cells, and/or intravascular endothelial hyperplasia were seen in more than 70% of VM. CD34 was highly expressed by endothelial cells of BVN and VA while D2-40 was specific for lymphatic vessels (LEC). SMA, CD31 and vWF/FVIIIRag were generally upregulated by capillary and mixed capillary-venous anomalies. VEGF expression and mast cells were increased in hemangioma. Conclusion: The overlapping clinical and histopathological characteristics of VM and BVN blur the distinction of vascular tumors and malformation. Although some were distinct BVN and VM of infancy and childhood, majority were acquired during the later decades of life indicating a possibility that these were probably reactive vascular proliferations. CD34 is the most consistent vascular endothelial cell marker while D2-40 is specific for LEC.