[Ultrastructural studies of central-type early squamous cell carcinoma of the lung].

Characteristics of the nuclei in histopathologic preparations obtained from a patient with bronchial carcinoma and two patients with microinvasive bronchial carcinoma were studied by transmission electron microscopy. In carcinoma in situ, the nuclei showed slight or moderate irregularity in the nuclear outline. The number of perichromatin granules was usually one to 10 per nucleus section. Formation of fibrillar centers was not marked. In microinvasive carcinoma, the nuclei were more irregular in nuclear outline than in carcinoma in situ. The number of perichromatin granule was usually more than 11 per nucleus section. Formation of fibrillar centers was predominant.