Abstract:

The cellular heterogeneity of lung carcinoma and ultrastructural diagnosis of neuroendocrine carcinoma of the non-small-cell type were studied. Methods: 46 cases of lung carcinoma were examined comparatively on light and electron microscopy. Results: 1 case(2.2%)of adenosquamous carcinoma was observed on light microscopy and 12(26.1%)cases of adenosquamous carcinoma on electron microscopy. N. S. G(neurosecretory granules)were identified ultrastructurally in 1 cases of adenocarcinoma and 2 cases of large cell carcinoma. Squamous, glandular and endocrine features were found together in one case diagnosed as adenocarcinoma on light microscopy. No case of neuroendocrine carcinoma of non-small-cell type was diagnosed on light microscopy, but 3 cases were diagnosed on electron microscopy. Conclusions:Our results indicated that lung carcinoma cell had high hetergeneity which appeared that some adenocarcinomas had cells with squamous characteristics, some squamous carcinomas had cells with glandular features, and both had cells with endocrine structures. The ultrastructural findings showed that some lung carcinomas were derived from stem cells of bronchial epithelium which possesed the ability of multipotential differentiation. Electron microscpy plays an important role in diagnosis of neuroendocrine carcinoma of non-small-cell type.

Key words: lung carcinoma, hetergeneity, ultrastructure