Angiogenic and lymphangiogenic microvessel density in recurrent pleomorphic adenoma Andresa B. Soares 1 , Vera C. de Arau´jo 1 , Priscila B. Juliano 2 , Albina Altemani 2 1 Centro de Pesquisa Sa ˜o Leopoldo Mandic, Campinas, SP, Brazil; 2 Department of Pathology, School of Medicine, State University of Campinas (UNICAMP), SP, Brazil BACKGROUND: Recurrent pleomorphic adenoma (RPA) is an uncommon and challenging disease. The aim of this study was to determine if there is a difference between RPA and the pleomorphic adenoma (PA) with- out recurrence related to tumor blood and lymphatic vascularization. Moreover, we compared the microvessel density (MVD) between cell-rich areas (predominance of epithelial cells) and cell-poor areas (predominance of myxoid and chondroid areas) of the stroma of PA and RPA. In addition, immunohistochemical staining for the Ki-67 antigen was conducted simultaneously to evaluate cell proliferation in PA and RPA. METHODS: A total of 19 cases of PA and 24 cases of RPA, blood, and lymphatic vessels were analyzed by immunohistochemical technique using the antibodies CD34, CD105, D2-40, and Ki-67. RESULTS: Comparing no recurrent with recurrent tumor, no significant difference was found in terms of lymphatic vessel density, MVD, and proliferation index. When MVD and proliferation index were compared with different areas in cellular composition (cell-rich and cell-poor areas), there was a significant difference in PA, as well as in RPA. CONCLUSION: This study shows that although RPA presents more aggressive clinical behavior than PA, there is no difference between tumor blood and lymphatic vascularization, suggesting that there is no correlation between vascularity and risk of recurrence. Furthermore, vascularized stroma in PA, as well as RPA, depends on the proportion of the cellular composition. J Oral Pathol Med (2009) 38: 623–629 Keywords: blood vessel; lymph vessel; pleomorphic adenoma; recurrence; vascular density Introduction Pleomorphic adenoma (PA) is the most common tumor of the salivary gland and accounts for 60% to70% of all neoplasms in the parotid gland (1). Recurrent pleomor- phic adenoma (RPA) occurs presumably when PA presents capsule rupture, incomplete resection of micro- scopic extensions beyond the pseudocapsule, or unap- preciated multifocal origin (2–4). The recurrence risk can range from 0.4 to 45% depending on the surgical technique (5–7): ranging from 20 to 45% following enucleation, 2–5% following parotid lobectomy, and 0– 0.4% following radical parotidectomy (8, 9). The greatest problem of the RPA is the difficulty of the treatment, due to factors such as: permanent facial nerve injury risk; multicentric origin, and increasing possible new recurrence (3, 10). There is also an increase of the malignant transformation risk, with rates varying between 1.4% and 16% (11, 12). Blood and lymphatic vascular systems are very important for supplying cells with nutrients and oxygen and also for removing excessive fluids, which are crucial tasks for homodynamic maintenance. Nowadays, spe- cial attention has been given to the role of neoplastic micro-environment influencing proliferation, invasion, and metastases (13–15). Vascularization, a part of this process, is an important issue for cell nutrition not only in malignant but also in benign tumor. Nevertheless, there are rare studies concerning the metabolism of benign tumors, even the recurrent ones (16–19). We studied lymphatic vascularization in PA, but particu- larly in the transition from adenoma to carcinoma (20). Regarding blood vessels, few studies have shown that PA is poorly vascularized (21), but depending on the cellularity of PA, which is variable, changes in the metabolic demand can be expected. The majority of RPA studies have been driven to tumor treatment and a few were directed to the search of special marker for recurrence and measuring the prolif- eration of the RPA cells. (2–4, 6, 12, 22–24). So far, there has been no investigation of the stroma pattern comparing PA with no recurrence and RPA. Based on the above considerations, the aim of this study was to determine if the tumor blood and lymphatic vascularization of RPA were different from those which did not develop recurrence. This was assessed in histological samples by measuring the blood microvessel density (MVD) using CD34 and CD105 antibodies, and lymphatic vessel density (LVD) with Correspondence: Dra. Andresa Borges Soares, Centro de Pesquisa Sa˜o Leopoldo Mandic, Rua Jose´ Rocha Junqueira13 Ponte Preta, 13045-755, Campinas, SP, Brazil. Tel: 55-19-32113636, Fax: 55-19- 32113635, E-mail: andresabs@hotmail.com Accepted for publication April 15, 2009 doi: 10.1111/j.1600-0714.2009.00794.x J Oral Pathol Med (2009) 38: 623–629 ª 2009 John Wiley & Sons A/S Æ All rights reserved interscience.wiley.com/journal/jop Journal of Oral Pathology & Medicine