[Histopathological study of carcinoma of the cervix stage Ia]

Seventy-three cases of microinvasive carcinoma of the cervix (restricted to Japanese criteria) were observed microscopically and compared with 67 cases of CIS. The lesion is more extended in stage Ia cases than those of CIS. There is a positive correlation between the depth of permeation and circular and longitudinal extensions of stage Ia cancer. Multiple invading lesions are observed in 52.9% of stage Ia cases. The lesion adjoining the microinvasive area is occupied by CIS in 50%. A tendency to differentiation is observed in 92.6% of Ia carcinoma, but in only 38.6% of CIS. We classified the invasive area into 3 grades: keratinizing type, large cell non-keratinizing type and small cell non-keratinizing type. Incidences among 654 invasive areas were calculated to be 12.4%, 68.3% and 19.3% respectively. Round cell infiltration around the invasive area is observed in 81.3% of cases. Mitotic frequency is lowest in the microinvasive area and highest in CIS cases. Cancer cells with a prominent nucleolus are found more often in the microinvasive area, than CIS and CIS areas of Ia cases. Among 95 cases with stromal invasions not longer than 3mm, vessel permeations are found in 4(4.2%) and confluent invasions in 7(7.4%).