Papillary syncytial metaplasia associated with endometrial breakdown exhibits an immunophenotype that overlaps with uterine serous carcinoma.

Uterine serous carcinoma (USC) is an aggressive variant of Type 2 endometrial carcinoma, which in most cases exhibits, at least focally, a papillary architecture. Occasionally, especially in small biopsy specimens, it may be difficult to distinguish between USC and a variety of metaplastic or reactive processes. In particular, papillary syncytial metaplasia (PSM), as a result of endometrial breakdown, may be confused with USC or its precursor serous endometrial intraepithelial carcinoma.

HMGA2 is commonly expressed in uterine serous carcinomas and is a useful adjunct to diagnosis.

Aims: Serous carcinoma is the prototype of type 2 uterine carcinoma. In many cases, establishing a diagnosis is straightforward, but problems can arise in that papillary variants of endometrioid carcinoma may be mistaken for serous carcinoma, and glandular variants of serous carcinoma may be misdiagnosed as endometrioid carcinoma. Markers such as p53, oestrogen receptor and p16 may be of use in problematic cases, but there is overlap and these may not therefore be of value in an individual case.

Misplaced Skene's glands: glandular elements in the lower female genital tract that are variably immunoreactive with prostate markers and that encompass vaginal tubulosquamous polyp and cervical ectopic prostatic tissue.

So-called ectopic prostatic tissue in the cervix and vaginal tubulosquamous polyps are rare morphologically similar lesions that may show positive immunohistochemical staining with prostatic markers. It has been suggested that they are related to paraurethral Skene's glands that are the female equivalent of prostatic glands in the male. We report a large series of lesions in women aged 23 to 81 years, found within the cervix (n=24), vagina (n=10), and vulva (n=2), which we believe to be a part of a spectrum of lesions derived from Skene's glands, either eutopic or more commonly misplaced during embryonic development.

HMGA2 is a sensitive but not specific immunohistochemical marker of vulvovaginal aggressive angiomyxoma.

Aggressive angiomyxoma is a rare mesenchymal neoplasm, which almost always occurs in the vulvovaginal region and which exhibits a marked tendency for local recurrence after excision. A wide range of other mesenchymal lesions occur in this region, which potentially mimic aggressive angiomyxoma to a variable extent. Because rearrangement of the HMGA2 gene has been shown in a significant percentage of aggressive angiomyxomas, we examined the expression of HMGA2 protein in this neoplasm and in a large number of other mesenchymal lesions occurring at this site, including many which were referred with a possible diagnosis of aggressive angiomyxoma.

CD56 is a sensitive and diagnostically useful immunohistochemical marker of ovarian sex cord-stromal tumors.

Ovarian sex cord-stromal tumors comprise a heterogeneous group of neoplasms with wide morphological diversity, and they can be mistaken for a variety of other tumors. Some types, including granulosa and Sertoli cell tumor, may be confused with a neuroendocrine neoplasm. CD56 is a widely used neuroendocrine marker with a high sensitivity for neuroendocrine tumors and is commonly used as part of a panel to distinguish between a neuroendocrine neoplasm and other tumors in the differential diagnosis.

A panel of immunohistochemical stains, including carcinoembryonic antigen, vimentin, and estrogen receptor, aids the distinction between primary endometrial and endocervical adenocarcinomas.

The histological distinction between a primary endometrial and a primary endocervical adenocarcinoma is often difficult, especially in small biopsy specimens. A preoperative distinction is important because primary surgical management differs between the two tumors. Cases of primary endometrioid endometrial (n=30) and primary endocervical (n=26) adenocarcinoma of endocervical type were stained immunohistochemically with the monoclonal antibodies against carcinoembryonic antigen (CEA), vimentin, estrogen receptor (ER), and 34 beta E12.