Abnormal epithelial cells recovered by bronchoalveolar lavage: are they malignant?

The recovery of neoplastic cells by bronchoalveolar lavage is useful in the diagnosis of lung cancer. Abnormal epithelial cells can also be recovered from patients with interstitial lung diseases who do not have cancer, and therefore the usefulness of lavage in the diagnosis of malignancy in this setting is unknown. In this study, we evaluated the diagnostic significance of abnormal lavage cells recovered from patients with diffuse parenchymal abnormalities and compared the usefulness of standard cytologic assessment, correlation with clinical features, and immunocytochemical staining for carcinoembryonic antigen (CEA) in identifying abnormal cells that are truly malignant. Thirty of 2,314 patients had atypical lavage cells, but in only nine was lung cancer demonstrated. Although most patients with clinical suspicion of malignancy had lung carcinoma (six of seven), one such patient did not have cancer, and three were shown to have unsuspected carcinoma. Cytologic criteria identified definitely malignant cells in only four of nine patients with lung cancer, indicating that the approach is not sensitive. Immunostaining of abnormal cells with anti-CEA antibodies proved helpful. All patients with lung malignancy had CEA+ cells (n = 9), and no patient whose abnormal cells were CEA- proved to have cancer (n = 17). Because only nine of 13 patients with CEA+ cells had lung malignancy, the test is not diagnostic, but it appears to limit the need for further evaluation to a smaller group of patients in whom cancer is likely to be present. When used together, cytopathologic findings, detection of CEA by immunocytochemical techniques, and clinical correlates proved useful in diagnosis of lung malignancy, but further improvements are still needed to improve diagnostic accuracy.