Background: The differential diagnosis between malignant mesothelioma (MM) and metastatic lung adenocarcinoma (MLA) often relies on immunohistochemical studies, with no individual immunomarker holding satisfactory discrimination ability.
Methods: We investigated the diagnostic accuracy of CD24 immunoreactivity on 134 patients including 69 cases of MM and 65 MLA.
Results: The expression of CD24 favoured MLA, with 57/65 cases showing positive cytoplasmic staining compared with 9/69 MM (p<0.001), whose immunopositivity pattern was prevalently membranous (7/9 cases).
Conclusions: CD24 positivity can accurately discriminate MM from MLA. Prospective studies are warranted to clarify whether CD24 could integrate with other immunomarkers to facilitate the diagnosis of mesothelial malignancies.