Low Grade Vulvar Intraepithelial Lesions: A Correlation Study among Koilocytosis, Viral Load, Ki-67, and P16
S Loghavi, EG Silva. Cedars-Sinai Medical Center, Los Angeles, CA
Background: In cervical intraepithelial neoplasms there is good correlation between Ki-67, p16 and the degree of dysplasia. Since in the vulva most intraepithelial lesions are low grade (LGVIL) and are associated with low risk HPV we decided to investigate the degree of correlation between koilocytosis, viral load, Ki-67, and p16 in these lesions.
Design: 13 vulvar biopsies from different patients diagnosed as LGVIL were reviewed and stained for Ki-67 and P16 by immunohistochemistry. Ki-67 was evaluated according to the level of the positive reaction as staining the lower third, lower and middle third and the entire full thickness of the epithelium. P16 positivity was defined as both nuclear and cytoplasmic staining in single cells or a band like pattern of staining. The presence of low and high risk HPV types were studied by in-situ hybridization and evaluated as the maximum number of positive cells in one high power field (HPF). 12 fibroepithelial polyps from the vulva were used as the controls for this study and were stained with the same methods.
Results: All cases of LGVIL were positive for HPV, 11 cases were positive for low risk (maximum 3-220 positive cells/HPF), 1 case was positive for high risk HPV (maximum 46 positive cells/HPF), and 1 case was positive for both low and high risk HPV (maximum 15 positive cells/HPF). Koilocytosis was absent in 3 cases and ranged between 1+ up to 3+ in the other 10 cases. Ki-67 was positive in the lower third of the epithelium in 3 cases, in the lower and middle part of the epithelium in 5 cases, and in the entire thickness of the epithelium in 5 cases. P16 was positive in single scattered cells in 6 cases, in a band like pattern in 1 case and negative in 6 cases. In the control group none of the fibroepithelial polyps showed ki-67 staining beyond the lower third of the epithelium. Only 1 case showed single cell p16 immunoreactivity. All cases were negative for low and high risk HPV.
Conclusions: 1. In LGVILs there is no correlation between the degree of the koilocytosis and the viral load. 2. There is no correlation between Ki-67 and HPV; low or high risk. Ki-67 can be positive in all layers of the epithelium. 3. There is no correlation between P16 and HPV; low or high risk. Therefore polypoid lesions that are not fibroepithelial polyps should be stained for HPV regardless of the presence of koilocytosis. The HPV screening should include both low and high risk HPV because a small percentage of cases were positive for high risk HPV. Ki-67 and p16 do not provide additional information.
Category: Gynecologic & Obstetrics
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 134, Tuesday Afternoon