TRANSBRONCHIAL BIOPSY IN LYMPHANGIOMYOMATOSIS OF THE LUNG - HMB45 FORDIAGNOSIS

We have investigated the presence of smooth muscle cells with immunore activity for melanoma-related marker HMB45 in pulmonary lymphangiomyom atosis (PLAM). Of 75 lung specimens, including a variety of lesions (o btained with both transbronchial and open lung biopsies), only PLAM (s ix specimens from three patients) showed the presence of HMB45-positiv e cells. In addition, 20 specimens of normal lung were unreactive with this monoclonal antibody. It is concluded that the smooth muscle cell s of PLAM regularly exhibit a peculiar phenotype, characterized by HMB 45 immunoreactivity, distinct from other smooth muscle proliferations; and the histological diagnosis of PLAM can be made when only a transb ronchial biopsy is available.