[Electron microscopy in the diagnosis of small cell lung cancer]

The paper deals with an ultrastructural classification of small cell lung cancer distinguishing between wholly-undifferentiated tumors which do not contain cells with organ-, tissue- or cytospecific features (group 1) and tumors which incorporate both undifferentiated and differentiated cells (group 2). Depending on certain cytospecific characteristics, group 2 tumors histologically identifiable as small cell lung cancer may prove to be endocrine cancer, squamous cell cancer, adenocarcinoma or a mixed type tumor incorporating differentiated cells of two or more patterns. There is a correlation between the ultrastructural features of small cell lung cancer and its response to radiation and chemotherapy.