Cytologic Features of Papillary Immature Metaplasia of Uterine Cervix

Kim, Hye Sun; Seon, Mee Im; Kim, Yee Jung; Kim, Hy Sook

Abstract

Papillary immature metaplasia (PIM) of the uterine cervix (immature condyloma) is a subset of low grade squamous intraepithelial lesion (LSIL) which is frequently associated with human papilloma virus (HPV) types 6 and 11. The histologic features of PIM include filiform papillae lined by evenly spaced immature metaplastic-type cells with frequent nucleoli, mild anisokaryosis, and a low mitotic index. To characterize the cytologic changes associated with PIM, we analyzed 14 cases of PIM from our file. We reviewed biopsy slides and the cervicovaginal smears taken proximate to the time of biopsy. Histologically, nine cases had either flat condyloma (7 cases) or high grade squamous intraepithelial lesion (HSIL) (2 cases). Cytologic changes included cells in various stages of maturation with karyomegaly (14 cases), cells with irregularities in the nuclear membrane (13 cases), intermediate cells with karyomegaly(13 cases), cells with binucleation (13 cases), and aborted koilocytes (11 cases). Cervicovaginal smears from all cases were interpreted as atypical squamous cells of undetermined significance (ASCUS), NOS or ASCUS, rule out squamous intraepithelial lesion (SIL) or LSIL in two cases with flat condyloma or HSIL in a case with severe dysplasia. PIM is a distinct histologic entity that can present with a spectrum of cytologic findings, but cytologic findings may resemble variable reactive conditions and immature HSIL. Therefore, it is difficult to diagnose PIM by cytology alone. However, the meticulous efforts for making the cytologic diagnoses which can induce active management of patients are recommended because PIM is a variant of LSIL and frequently has a flat condyloma or HSIL.