The particularities of lymphangiogenesis in different molecular types of breast cancer are virtually unknown and the contribution of microenvironment to this process has been ever less investigated. In the present study, we evaluated the relationships between lymphatic microvessel density (LMVD), mast cell density (MCD) and the different molecular subtypes of breast cancer. Molecular classification of breast tumors by immunohistochemistry was followed by the detection of mast cells and lymphatic vessels on the same slide by immunohistochemical double-stain method, using the lymphatic endothelial cell marker D2-40 and the mast cell tryptase. Mast cells and lymphatic vessels were simultaneously counted in the tumoral and peritumoral areas and results were compared with the molecular type, grade, lymphovascular invasion and lymph node status. Significant positive correlations were found between peritumoral MCD and LMVD for the luminal type-A breast cancers (p=0.025) and also for basal-like carcinomas (p=0.029). Moreover, a significant positive correlation was found between peritumoral and intratumoral MCD for basal-like carcinomas (p=0.009) and for overall MCD and LMVD. Low or inverse correlations between MCD and LMVD were also observed in other molecular subtypes of breast cancer. Our results strongly support that mast cells in the tumor microenvironment are keyplayers, involved in the development of tumor lymphatic vessels for some molecular subtypes of breast cancer.