p53 immunostaining as a significant adjunct diagnostic method for uterine surface carcinoma - Precursor of uterine papillary serous carcinoma

Uterine papillary serous carcinoma (UPSC) is a biologically aggressive carc inoma that causes a disproportionate number of endometrial cancer deaths be cause of its dismal clinical outcome. Although the precursor lesion of UPSC has been suggested both morphologically and molecularly, diagnosis continu es to represent a challenge to surgical pathologists, particularly in biops y specimens, largely in part because of its multiple histologic patterns an d many benign morphologic mimics. In this study, we used p53 immunohistoche mical staining as an adjunct test to correctly identify six cases of uterin e surface carcinoma (USC) prospectively and three cases retrospectively. Bo th sensitivity and specificity for this immunostaining method approached 10 0% when the cutoff score of p53 overexpression was 7 or higher. The precisi on estimated by receiving operating characteristic curve was 100%, indicati ng that the diagnostic value of the score for p53 overexpression was very h igh. p53 immunohistochemical staining was considered a significant adjunct diagnostic method for the probable precursor lesion of UPSC. The probable p recursor lesion of UPSC, previously referred to as endometrial intraepithel ial carcinoma or endometrial carcinoma in situ, appears to represent the ea rly phase of UPSC. However, unlike its names would suggest, this lesion is often multicentric and behaves in a more aggressive fashion than regular in situ carcinomas. For this reason, we prefer the term uterine surface carci noma, a term that is more descriptive and less restrictive, to emphasize th e unique aggressive nature of the UPSC precursor lesion. The reason we post ulate using the term uterine surface carcinoma rather than endometrial intr aepithelial carcinoma or endometrial carcinoma in situ is that the latter t erms would seem define a neoplastic process confined to the endometrial epi thelium without potential for metastasis. In reality, the precursor lesion of UPSC has a tendency to stromal and vascular space involvement as seen by the presence of stromal and vascular invasion in one of the prospectively identified USC cases. Therefore, the term uterine surface carcinoma is sele cted to alert clinicians that this early carcinoma has features of carcinom a in situ, but still carries a potential for metastasis.