PECAM1 and lymphangioma: Macro-cystic, micro-cystic and combined forms of LM are distinguished in the clinical diagnosis, the cysts being lined by lymphatic endothelial cells (LECs), which express typical LEC markers such as LYVE-1, Podoplanin (PDPN), PROX1, VEGFR-3 and CD31/PECAM-1 [1–5], although, however, the expression of PDPN/D2-40 has not been found in 4 of 12 LM [6].