[Correlation between the electron microscopic picture of small cell cancer of the lung and treatment results].

Electronmicroscopic study of 35 small-cell lung carcinomas showed these to be a group of lung carcinomas having different histogenesis (cytogenesis). Apart from carcinoma without signs of differentiation, this group also includes squamous-cell carcinoma, adenocarcinoma, apudoma and mixed carcinoma with various differentiation of tumour cells. A certain correlation between the ultrastructural features of the tumour and its susceptibility to the treatment is established. Small-cell carcinomas consisting of undifferentiated cells are most susceptible. A relatively good prognosis can be expected when a variant with the endocrine differentiation of tumour cells is treated. Tumours interpreted light microscopically as small-cell carcinoma but ultrastructurally identified as having squamous-cell differentiation, or as adenocarcinoma and mixed carcinoma have the least favourable prognosis after treatment.