Transthoracic aspiration biopsy. The occurrence and significance of alveolar epithelial cells.

: Alveolar epithelial cells in pulmonary aspirates sometimes appear with a pronounced nuclear atypism which may give rise to diagnostic difficulties. An analysis has been performed of the occurrence and morphology of alveolar epithelial cells in a series of histologically-verified transthoracic aspiration biopsies not containing clear-cut malignant tumour cells. Alveolar epithelial cells, as well as atypism of these cells, are more often seen in biopsies from histologically malignant cases than in benigh cases. Their presence in a pulmonary aspirate may be due to a chronic obstruction atelectasis. In cases with tumour-like configuration of the alveolar epithelial cells, an open pulmonary biopsy is recommended, as it seems impossible to decide whether such findings represent a neoplastic or a reactive process.