PAPILLARY ADENOCARCINOMA ARISING IN PLACENTOID BULLOUS LESION OF THE LUNG - REPORT OF A CASE WITH IMMUNOHISTOCHEMICAL STUDY

We report the case of a 52-year-old man with papillary adenocarcinoma arising in placentoid bullous lesion of the lung, which is a rare cyst ic lung disease. Macroscopically, the cyst contained a soft villous tu mor closely resembling the placental chorionic villi of early gestatio n. Histologic examination revealed the tumor to be papillary adenocarc inoma with an abundant stromal core, which comprised vascular and lymp hatic vessels, lymphocytes, fat cells, and smooth muscle. Immunohistoc hemically, adenocarcinoma cells were positive for CAM 5.2, epithelial membrane antigen, and PE10 (antisurfactant apoprotein A antibody). The se results indicate that the adenocarcinoma was derived from the compo nent epithelial cells of the cyst. Based on the tumor's macroscopic an d microscopic appearance and on the results of the immunohistochemical studies, we conclude that the cystic tumor in our case arose in a pla centoid bullous lesion of the lung.