Differing Lymphatic Vessels Density in Salivary Adenoid Cystic Carcinoma and Pleomorphic Adenoma

Benign and malignant tumours are known to express various factors inducing lymphangiogenesis. Despite their different biological behaviour, salivary pleomorphic adenomas (PA) and adenoid cystic carcinomas (SACC) show similar lymphatic network. Authors compare density of lymphatic network in these tumours. The retrospective study included 20 SACC and 20 PA from salivary tumours. Lymphatic vessel density (LVD) was identified using D2-40 antibody and counted. In SACC, intratumoral, respectively peritumoral, lymphatic vessels were identified in 100 %, respectively 93.8 %, of cases. The intratumoral and peritumoral LVD did not significantly differ from each other. However, they both were higher than normal parenchyma density. In PA, intratumoral LVD, with a single exception, revealed values of 0 and 1. The intratumoral was found to be lower than peritumoral density. The LVD in healthy gland, similar to peritumoral one, was significantly higher than intratumoral values. Direct comparison showed intratumoral and peritumoral LVD in PA to be lower than in SACC. This study comparing LVD in PA and SACC revealed higher values in SACC, outnumbering those in healthy salivary parenchyma and PA. It suggests the capability of this biologically aggressive neoplasm to induce lymphangiogenesis.