Squamous intraepithelial lesions arising in benign endocervical polyps: a report of 9 cases with correlation to the Pap smears, HPV analysis, and immunoprofile.

Endocervical polyps are common benign lesions that typically arise in the endocervical canal of women from 40 to 60 years old. The reported incidence of squamous intraepithelial lesion (SIL) occurring in an endocervical polyp is typically less than 1/1,000 (0.1%). We report on 9 cases of SIL arising in otherwise classic benign endocervical polyps; these lesions were from a pool of about 1500 endocervical polyps for an incidence of approximately 0.5%. Five cases were low-grade SIL; of the 4 cases of high-grade SIL, 1 was associated with an invasive squamous cell carcinoma. In 8/9 cases, there was no evidence of SIL on colposcopic examination or biopsy of the remainder of the cervix. There were 12 Pap smears (either concurrent or from 6 mo to 2 yr before the biopsy-proven SIL) taken from the 9 women and most (10/12%-83%) were diagnosed as normal (7), atypical squamous cells of undetermined significance (ASCUS), favor reactive changes (1), or ASCUS (2) whereas the other 2 (17%) smears were diagnosed as low-grade SIL. Human papillomavirus DNA was evident in 7/8 (88%) of the polyps with SIL as determined by in situ hybridization. We conclude that cervical SILs can occur de novo in endocervical polyps, their incidence may be increasing, and, due to their presence in the endocervical canal, where they are much less accessible to sampling with a cytobrush/spatula, may not be evident in the Pap smear.