Small cell carcinoma is most malignant in lung cancer. Its prognosis varies according to the histologic subtypes. So, it is important to make the early diagnosis of histologic subtypes for the establishment of suitable treatment. We found that the cytological examination of the bronchial brushing specimens was useful for the early diagnosis of histologic subtypes.We made histological and cytological examination in twenty-three cases with small cell lung cancer. In the examination, it was revealed that cell arrangement, sizes and shapes of nuclei on the cytological specimens were important to make an accurate diagnosis for the histologic subtypes.
The following cytological features are manifested for each subtype:(1) for oat cell type, round or ovoid nuclei are very small in size and naked, (2) for intermediate fusiform cell type, naked and spindle nuclei are arranged with a ribbon or a pallisade-like pattern, (3) for intermediate polygonal cell type, large and pleomorphic nuclei are arranged irregularly or with a ribbon-like pattern.