[1113] The Spectrum of Non-Cervical Neoplastic/Dysplastic Lesions of the Uterine Cervix with p16INK4a Immunohistochemical Positivity Encountered in the Uterine Cervical and Endometrial Biopsy Samples in the Daily Surgical Pathology Practice

HG Kaspar, XM Zhang. Geisinger Health System, Wilkes Barre, PA

Background: Overexpression of p16 is described in cervical intraepithelial neoplasia associated with oncogenic human papilloma virus (HPV) infections and in several neoplastic and non-neoplastic gynecologic conditions. Immunohistochemical testing with p16 is therefore broadly used in the diagnosis of dysplastic and neoplastic cervical lesions. The spectrum of lesions with p16 positive staining encountered on the uterine cervical and endometrial biopsy samples in the daily surgical pathology practice is evaluated in this retrospective study.
Design: This is a retrospective review of 213 cervical and endometrial tissue samples where immunohistochemistry using p16, MIB-1 and in-situ hybridization for HPV was performed as a part of a diagnostic work-up differentiating neoplastic/dysplastic versus reactive/metaplastic epithelium, and cervical versus metastatic origin of a cervical lesion.
Results: There were 167 cases with all p16 and MIB-1 immunohistochemistry, and HPV in-situ hybridization available for evaluation. Of these 167 cases, 97 samples demonstrated p16 positive staining distributed as follows: 6 invasive squamous cell carcinomas and 4 invasive adenocarcinoma of the cervix, 36 cases of HGSIL, 8 in-situ adenocarcinoma, and 24 LGSIL. Other malignant conditions of non-cervical origin with strong and diffuse p16 staining, and a high MIB-1 proliferative index included 3 cases of endometrial adenocarcinomas and 2 cases of carcinosarcoma with direct extension to the cervix, two cases with fragments of endometrial mucinous carcinoma obtained on endocervical samples, two cases of metastatic tubal carcinoma, three cases of metastatic serous carcinoma of the ovary and peritoneum, and one case of papillary serous carcinoma with HPV inclusions on in-situ hybridization. The spectrum of the non-neoplastic conditions included 12 cases of endometrial squamous metaplasia with a mosaic pattern and predominant cytoplasmic staining, six tubal metaplasias and three cases with cervical endometriosis.
Conclusions: While it is now established that p16 immunohistochemical testing is a valuable tool in the diagnosis of cervical neoplasia/dysplasia, in particular when used in conjunction with MIB-1 and in-situ HPV testing, the current study demonstrates p16 positivity in several other neoplastic and non-neoplastic conditions encountered in the daily evaluation of cervical and endometrial tissue samples.
Category: Gynecologic & Obstetrics

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 175, Tuesday Morning

 

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