Transthoracic needle biopsy in the diagnosis of large-cell neuroendocrine carcinoma of the lung.

To determine the effect of cytological diagnosis, fine-needle aspiration and brush cytology on lung tumors and core-needle biopsy, we retrospectively reviewed 11 cases of large-cell neuroendocrine carcinoma (LCNEC) found in our archives between the years 1997 and 2004. The preoperative cytological diagnosis of LCNEC is challenging because of the broad histologic similarity to other neuroendocrine tumors of the lung. The original cytologic diagnosis was LCNEC in nine of the cases while the remaining two were misdiagnosed as small-cell lung carcinoma. Smears were composed of clusters of intermediate-size cells with amphophylic cytoplasm, some with large nuclei and prominent nucleoli. In two of the cases there was discordance between the cytological findings and the immunohistochemical results. The cytological findings were correlated with histopathological observations.