Microinvasive carcinoma of the cervix: Site of first focus of invasion

Objective: To evaluate the topography of the first invasive focus in microi nvasive squamous cell carcinoma of the uterine cervix. Methods: We studied 120 formalin-fixed and paraffin-embedded cold-knife con ization specimens processed as step-serial sections. Four types of microinv asion were distinguished according to site: type I (ectocervical outside th e last cervical gland), type II (ectocervical between the external os and t he last gland and in connection with the surface epithelium), type III (ect ocervical between the external os and the last gland but deep in cervical g lands), and type IV (intracervical and in connection with the surface epith elium). Results: A total of 142 early invasive foci were seen in the 120 cones. A s ingle focus was seen in 106 (88%) specimens, whereas 14 (12%) had more than one focus. The foci were classified as type I in 16 (11%), type II in 31 ( 22%), type III in 70 (49%), and type IV in 25 (18%) cases. Conclusion: One half of the early invasive foci originated at the surface e pithelium (types I, II, IV), either at the ectocervix (types I, II) or in t he endocervix (type IV). (Obstet Gynecol 2001;97:890-2. (C) 2001 by The Ame rican College of Obstetricians and Gynecologists.).