“…4,5,24,25 In particular, bronchoalveolar carcinoma must be ruled out. Subtle morphologic cytologic characteristics suggesting either RPII or carcinoma have been listed, 4,24,25 but these features have considerable overlap 16 and are better evaluated on Papanicolaoustained preparations than on MGG-stained ones. 26 Further, no single immunohistochemical marker accurately discriminates between both cell types; e.g., RPII may react with monoclonal antibodies against carcinoembryonic antigen and B72.3 (a marker for the tumor-associated TAG-72 antigen).…”