Small cell lung carcinoma: Clinicopathological, immunohistochemical, and ultrastructural study

Sixty‐seven cases of small cell lung carcinoma (SCLA) in Tri‐Service General Hospital (TSGH) during the past 16 years were studied. For patients with extensive stage of disease, the mean survival time and 2‐year survival rate were 7.2 months and 3.1% versus 13.4 months and 16.7% for patients with limited stage. A better prognosis was obtained by treatment with a combination of intensive chemotherapy and radiotherapy. Immu‐nohistochemical studies were performed by the peroxidase‐antiperoxidase method. The positive rates in descending order were bombesin (80%), synaptophysin (74.3%), neurofilament (68.6%), neuron‐specific enolase (60%), low molecular weight cytokeratin (54.3%), high molecular weight cytokeratin (25.7%), chromogranin‐A (22.9%), adrenocorticotrophic hormone (0). Seven cases were examined and found to be ultrastructure; only 3 cases were found to contain neurosecretory granules. We emphasize that electron microscopy is not necessary as a routine diagnostic procedure, while light microscopy should be employed whenever possible; the immunohistochemical study should be considered within this context.