[1151] PAX8 in Conjunction with p16 and ER Aids in the Distinction between Mesonephric Proliferations and Adenocarcinomas of Cervix

Abha Goyal, Bin Yang. Cleveland Clinic Foundation, Cleveland, OH

Background: Mesonephric remnants, usually located deep in the lateral cervical wall, may become hyperplastic resulting in a florid proliferation. These can be misinterpreted as malignant and confused with endocervical adenocarcinomas. Recent data has shown PAX2 to be diffusely expressed in mesonephric remnants/hyperplasias and rarely in endocervical adenocarcinomas. PAX8 is a related transcription protein that is expressed in tissues of mullerian and wolffian origin. In this study, we have investigated the utility of an immunohistochemical panel comprising of PAX8, ER and p16 in the differential diagnosis between mesonephric proliferations and cervical adenocarcinomas.
Design: A database search was conducted for cases of mesonephric remnants/hyperplasia/carcinoma of cervix and invasive cervical adenocarcinomas from January 2001 to December 2011. The corresponding slides and paraffin blocks were retrieved. Immunohistochemical stains for PAX8, ER and p16 were performed with adequate controls using the avidin-biotin peroxidase technique on the most representative tissue. The staining pattern was recorded as positive (diffuse, focal or patchy) or negative with the intensity of staining as weak, moderate or strong.
Results: The search yielded 27 cases of mesonephric proliferations of cervix (15 mesonephric remnants, 11 mesonephric hyperplasias and 1 mesonephric carcinoma) and 16 cases of cervical adenocarcinomas (15 usual type and 1 adenoma malignum). Immunohistochemically, all the mesonephric proliferations displayed a consistent staining pattern - diffusely and strongly positive for PAX8, negative for ER and patchy and weak staining for p16. The cervical adenocarcinomas exhibited a variable staining pattern.[table 1]
Conclusions: The mesonephric proliferations, regardless of being benign or malignant, showed a consistent immunostaining pattern with PAX8, p16 and ER. In contrast, the usual type of endocervical adenocarcinomas showed a uniform strong and diffuse staining pattern with p16, but stained heterogeneously with PAX8 and ER. Our study suggests that a panel of immunostains composed of PAX8, p16 and ER is useful in the distinction between mesonephric proliferations and cervical adenocarcinomas.
Category: Gynecologic & Obstetrics

Table 1. Immunostain profile for cervical adenocarcinomas
 PatternNumber of casesPatternNumber of casesPatternNumber of cases
Usual typeNegative2Negative6Strong (diffuse)15
 Moderate (difffuse)7Moderate (diffuse)5  
 Strong (diffuse)4Weak (focal)4  
 Weak (diffuse)2    
Adenoma malignumStrong (diffuse)1Negative1Weak (patchy)1

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 186, Wednesday Afternoon


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