Comparison of the Blood and Lymphatic Microvessel Density of Pleomorphic Adenoma and Basal Cell Adenoma

Abstract

BACKGROUNDPleomorphic adenoma (PA) is the most common tumor of the salivary gland, while basal cell adenoma (BCA) is an uncommon neoplasm. Blood and lymphatic vessels are crucial for tumor metabolism. The aim of this study was to compare the blood and lymphatic vascular density and vascular and endothelial growth factor (VEGF) expression in PA and BCA tumors. In addition, cell proliferation was evaluated in these tumors.METHODSBlood and lymphatic vessel content, VEGF expression, and cell proliferation were analyzed in 30 cases of PA and 13 cases of BCA by immu-nohistochemistry using antibodies for CD34, CD105, D2–40, VEGF, and Mcm−2.RESULTSRegarding CD34 and CD105 expression, PA demonstrated a high vascularity and a low number of positive vessels, respectively. D2–40-positive lymphatic vessels were mainly located in the tumor capsules, with small intratumoral lymphatic vessels observed occasionally. VEGF expression revealed a remarkably heterogeneous immunoreactivity, alternating from weak or negative to positive or intense. BCA presented significantly higher CD34, CD34, CD105, D2–40, and VEGF expression compared to PA. No significant difference was found in cell proliferation between the tumors.CONCLUSIONAlthough PA and BCA are considered part of the same spectrum of differentiation, this study showed that the blood and lymphatic vascularization of these tumors is different.

Comparison of lymphatic vessel density and expression of VEGF-C and VEGF-D lymphangiogenic factors in Warthin's tumours and oncocytic adenomas

“…This finding corresponded to the markedly lower intratumorous lymphatic vessel density in the latter lesion. As it is evident from the presented and previously published studies 28,44,46 , pleomorphic adenoma, oncocytic adenoma and basal cell adenoma reveal similar predominance of the peritumorous capillaries over the scarce intratumorous ones. This is not surprising considering that the latter are found in higher number only in some carcinomas, thus, increasing their metastatic capability.…”

“…Scarcity of these lymphatics has been reported in primary and recurrent pleomorphic adenomas, too 44,28 . In basal cell adenoma, the number of intratumorous vessels was also shown to be low, but exceeding that in pleomorphic adenoma 46 . In general, the minimal number or even absence of intratumorous lymphatics is considered to be due to the growth of neoplastic cells that increases interstitial pressure, thereby collapsing and/or pushing these vessels to the tumour periphery 57,58 .…”

“…Analogic distribution of lymphatic network has been reported not only in WT (ref. 47 ) but also in pleomorphic adenoma 28,44 and basal cell adenoma 46 . In our cases of WT, the intratumorous lymphatics were seen solely in the lymphoid stroma.…”

“…This conclusion was later confirmed by Soares et al 45 . In their subsequent study 46 , these authors reported stronger VEGF immunoreactivity in basal cell adenoma than in pleomorphic adenoma. This finding corresponded to the markedly lower intratumorous lymphatic vessel density in the latter lesion.…”

“…Neither primary nor recurrent lesion showed any intratumorous lymphatics 44,45 . Remarkably, Soares et al 46 demonstrated significantly higher density of the intratumorous lymphatic network in basal cell adenomas than that of pleomorphic adenoma. Up to now, only one paper was found on the lymphatics in Warthin's tumour (WT), revealing a rich lymphatic network in the lymphoid component, exceeding that in the adjacent parotid parenchyma and lymph nodes 47 .…”