BACKGROUND: Some cervical/vaginal Papanicolaou (Pap) smears previously diagnosed as normal in women with a high grade squamous intraepithelial lesion (HSIL) are found to contain abnormal cells on retrospective review. This study characterized and quantitated such cells in 100 Pap smears. METHODS: One hundred prior negative Pap smears from 49 women with a newly diagnosed HSIL were rescreened, as were 107 negative Pap smears from 100 women with normal subsequent smears. Cases were assorted randomly so that the rescreener was unaware of the subsequent follow-up. RESULTS: All 12 Pap smears found to contain atypical mature and immature metaplastic cells belonged to the group with a subsequent HSIL (P = 0.001). In addition, 18 of the 100 previously negative Pap smears (18%) had immature metaplastic cells without nuclear atypia compared with 4 of 107 Pap smears (4%) in the control group (P = 0.0007). CONCLUSIONS: This study supports the observations of other authors that atypical metaplastic cells, especially those of the immature type, are associated with HSIL. These cells most likely are HSIL lesional cells, which are not easily recognizable as such. Immature metaplastic cells without atypia also were shown to be associated significantly with HSIL in this study. These cells may be unrecognizable lesional cells or a marker of increased risk for HSIL and deserve further study.
BACKGROUND: Some cervical/vaginal Papanicolaou (Pap) smears previously diagnosed as normal in women with a high grade squamous intraepithelial lesion (HSIL) are found to contain abnormal cells on retrospective review. This study characterized and quantitated such cells in 100 Pap smears. METHODS: One hundred prior negative Pap smears from 49 women with a newly diagnosed HSIL were rescreened, as were 107 negative Pap smears from 100 women with normal subsequent smears. Cases were assorted randomly so that the rescreener was unaware of the subsequent follow-up. RESULTS: All 12 Pap smears found to contain atypical mature and immature metaplastic cells belonged to the group with a subsequent HSIL (P = 0.001). In addition, 18 of the 100 previously negative Pap smears (18%) had immature metaplastic cells without nuclear atypia compared with 4 of 107 Pap smears (4%) in the control group (P = 0.0007). CONCLUSIONS: This study supports the observations of other authors that atypical metaplastic cells, especially those of the immature type, are associated with HSIL. These cells most likely are HSIL lesional cells, which are not easily recognizable as such. Immature metaplastic cells without atypia also were shown to be associated significantly with HSIL in this study. These cells may be unrecognizable lesional cells or a marker of increased risk for HSIL and deserve further study.