D2-40 labeling in lymphangiomyoma/lymphangiomyomatosis of the soft tissue: further evidence of lymphangiogenic tumor histogenesis

We examined ten cases of extrapulmonary lymphangioleiomyoma/lymphangioleiomyomatosis (LAM; all patients female; median age 46.5 years) for immunohistochemical labeling with a monoclonal antibody against podoplanin (D2-40), which is specific for lymphatic endothelial lining. We found positive staining in thin-wall branching vessels reflecting the lymphatic nature of tumor vessels in all cases tested. In contrast, perivascular (HMB-45 positive) myoid cells were not detected by D2-40. The D2-40 labeling confirms the current concept of lymphangiogenic origin of the tumor vessels in LAM. In addition, this study makes a further contribution to the immunohistochemical mapping of this antibody in vascular tumors. Finally, the use of this commercially available antibody provides an additional help in the differential diagnosis of LAM from other soft tissue tumors.