Immunohistochemical identification of lymphatic vessels. Immunohistochemical identification of lymphatic vessels using D2-40 antibody against podoplanin in an oropharyngeal (A) and a supraglottic tumour (E). Detection of intratumoural lymphatics in an oropharyngeal (B) and a supraglottic tumour (F). Detection of peritumoural lymphatics in a supraglottic tumour. The basal layer of the epithelium and the margin of the tumour mass gave positive signal for podoplanin (C). Detection of peritumoural lymphatics in a glottic tumour that stained positive for podoplanin (G). Example of one representative podoplanin positive tumour cell embolus inside a podoplanin positive lymphatic vessel of an oropharyngeal (D) and a supraglottic carcinoma (H). Scale bar, 250 μm.