Introduction: Small cell lung carcinoma (SCLC) is a very aggressive neoplasm. Accurate and quick diagnosis is crucial to initiate proper treatment. The aim of this study was to establish the value of initial cytological diagnosis and to present typical cytological features of SCLC.
Material and methods: We reviewed 116 cases of SCLC confirmed by cytology in: bronchial brushings, pleural fluids, and fine needle aspiration biopsies (FNAB).
Results: In 77% of SCLC cases, the diagnosis was established only by cytology; in 23% of cases, both cytological and histological recognition was possible. Cytology of SCLC was initially uncertain in 12%, and histology was uncertain in 30% of the cases. The morphology of SCLC cells was not uniform, and often a mixture of non-small atypical cells and bronchial epithelial cells with signs of metaplasia was observed. There were four cases of combined cell type with large cell carcinoma and two with adenocarcinoma. The main diagnostic problem was to distinguish small cell lung carcinoma from lymphomas, and from cancer consisting of small cells with the cytological features of non-small cell carcinoma.
Conclusion: Diagnosis of SCLC in cytological smears is accurate, and final diagnosis is based on light microscopy. In the differential diagnosis, other tumours of small cells have to be taken into account.