Differential Diagnosis between Small Cell Carcinoma and Adenocarcinoma of Lung in Fine Needle Aspiration Cytology.

Distinguishing small cell carcinoma from other lung malignancies is of great clinico-therapeutic significance. Small cell carcinoma is an aggressive tumor with a tendency to metastasize early. Survival time if untreated is low but this tumor is highly responsive to chemotherapy. We have occasionally experienced difficulties in differentiation between adenocarcinoma and small cell carcinoma of the lung in fine needle aspiration cytology (FNAC). The aim of this study was to investigate the possibility of distinguishing small cell carcinoma from adenocarcinoma of the lung in FNAC. We evaluated cytomorphological features of FNAC specimens from 62 small cell carcinomas and 57 adenocarcinomas from the lung that were confirmed by biopsy and/or immunohistochemistry on cell block. Cytomorphological details of the two tumors were compared. Nuclear smearing and nearly absent cytoplasm were the most distinct findings in small cell carcinoma compared to adenocarcinoma (p