This study was designed to assess intraobserver and interobserver agreement in the diagnosis of 56 endometrial specimens by five European expert gynecologic pathologists using the WHO classification and to establish which histologic features are significantly associated with each classification category. The seven categories were simple hyperplasia, complex hyperplasia, atypical hyperplasia, well-differentiated adenocarcinoma, proliferative endometria, secretory endometria, and other. Slides were reviewed twice for diagnosis, with accompanying evaluation of a checklist of histologic features. These seven categories were eventually reduced to four and three for the purposes of data analysis. The four modified diagnostic categories consisted of hyperplasia (previously simple hyperplasia and complex hyperplasia), atypical hyperplasia, well-differentiated adenocarcinoma, and cyclical endometrium (previously proliferative, secretory, and other). The three diagnostic categories consisted of hyperplasia, endometrioid neoplasia (previously atypical hyperplasia and well-differentiated adenocarcinoma), and cyclical endometrium. Intraobserver and interobserver agreement was assessed using the percentage agreement and kappa statistics. The associations among the various histologic features and diagnoses was analyzed using multiple logistic regression to identify those features that were useful for distinguishing diagnostic categories. When using seven categories, kappa values ranged from 0.53 to 0.74 (percentage agreement, 61-79%) and from 0.33 to 0.59 (percentage agreement, 43-63%) for intraobserver and interobserver agreement, respectively. When using four categories, kappa values ranged from 0.68 to 0.73 (percentage agreement, 77-80%) and from 0.39 to 0.64 (percentage agreement, 54-73%) for intraobserver and interobserver agreement, respectively. When using three categories, kappa values ranged from 0.70 to 0.83 (percentage agreement, 80-89%) and from 0.55 to 0.73 (percentage agreement, 70-82%) for intraobserver and interobserver agreement, respectively. Data were analyzed in each diagnostic category. When using four or three diagnostic categories, the mean intraobserver and interobserver agreements varied less between categories and achieved higher values, with smaller 95% confidence intervals. The mean percentage agreement was lowest for complex hyperplasia and for atypical hyperplasia. For distinguishing cyclical endometrium versus hyperplasia, the useful histologic feature was glandular crowding. For hyperplasia versus atypical hyperplasia and for hyperplasia versus endometrioid neoplasia, the useful features were nuclear enlargement, nuclear pleomorphism, vesicular chromatin, and nucleoli, but of these, only nuclear pleomorphism achieved substantial mean intraobserver and interobserver agreements. For discriminating atypical hyperplasia from well-differentiated adenocarcinoma, the only useful feature was stromal alterations, which achieved only fair mean intraobserver and interobserver agreements. In summary, in endo...

We review the current knowledge on human yolk sac tumours (YSTs) 50 years after their initial description. Their complex nomenclature and histogenesis stress the fact that they are not a discrete entity, but represent a multifaceted group of neoplasms, for which the term primitive endodermal tumours would be more appropriate, accounting for their capacity to differentiate into various extraembryonal and somatic cell types. Different histological patterns of human YSTs correlate with the developmental potential of primitive endoderm and mesenchyme, but they are also similar to some murine experimental tumours. Exceptionally, YSTs replicate the tubular structures of the human yolk sac and allantois. Endodermal somatic differentiation reproduces pulmonary, intestinal and hepatic tissues and are identical with some, embryonal-type endodermal, gastric and lung carcinomas, which are indistinguishable from YSTs. YSTs may show an overgrowth of their mesenchymal (sarcomatous) and epithelial components (such as mucinous carcinoma or carcinoid) and also be a source of haematological malignancies. YSTs associated with non-germ cell tumours probably originate from malignant pluripotent somatic stem cells. Only AFP and glypican-3 are characteristic immunohistochemical markers. Pluripotent antibodies (SALL4, Lin28, IMP-3) help in differential diagnoses, while some differentiation markers (CDX2, TTF-1, HepPar1) facilitate recognition of unusual variants of YSTs.

Sixty cases of uterine adenomatoid tumors (ATs) are reported. All except four were incidental findings in hysterectomy specimens, three of these being discovered preoperatively as large multicystic tumors. ATs were classified into two distinctive macroscopic patterns: small, solid tumors and large, cystic ones. The 56 small, solid ATs ranged from 0.2 to 3.5 cm, (average 2.1 cm); 48 were nodular and 8 diffuse. The four large, cystic tumors ranged from 7 to 10 cm. Inflammation occurred in 65% of the tumors, and a smooth muscle reaction, identified by an increased Ki-67 index, was present in most cases. Both types were histologically similar except for the presence of short papillae in cystic tumors, which also showed serosal involvement. Both were immunoreactive for cytokeratins, calretinin, HMBE-1, and vimentin. Estrogen and progesterone nuclear receptors and EMA were negative. These tumors represent a spectrum ranging from small and solid to large and cystic ATs in the female genital tract, whereas outside the genital tract they are morphologically similar to multicystic mesothelioma. Although a reactive origin for ATs often seems plausible, especially when inflammation is present, their neoplastic nature should not be ignored.

The clinical, morphological, and immunohistochemical findings in six cases of ovarian endometrioid tumors (five endometrioid carcinomas and one carcinosarcoma) with a yolk sac tumor (YST) component are described. The age of the patients ranged from 31 to 73 years (average, 53), and only two patients were premenopausal. Two cases were stage Ia tumors, three stage III, and one stage IV. A substantial postoperative elevation of alpha-fetoprotein (AFP) was seen in two patients and a mild increase in another two. All six patients had surgery and postoperative cisplatin-based chemotherapy regimens, four of whom died of tumor 3 to 14 months after surgery without response to treatment. Only a stage Ia patient is alive and well 1 year after surgery. The tumors were large (average, 17 cm). Benign endometrioid lesions were found in the homolateral ovary in two cases and in the contralateral ovary in another two. All cases had endometrioid ovarian carcinomas (EOC) of various types admixed with typical YST components. Immunohistochemically, EOC areas differed from YST in their positivity for OC 125, CA 19.9, and nuclear estrogen and progesterone receptors and in their negativity for AFP, which was conspicuously positive in the YST areas. The clinicopathological profile of ovarian endometrioid tumors with YST also differs from that of YST in that it occurs in the same age range as EOC, it shows coexistence of benign endometrioid lesions, and it has a poor response to chemotherapy. The histological pattern in transitional areas may be difficult to differentiate from "endometrioid-like" (enteroblastic) YST and clear cell tumors. Ovarian endometrioid tumors with YST component should be considered a variant of endometrial carcinoma. Its recognition is necessary in view of its unusually aggressive behavior and poor prognosis.

Endometrial metaplasias and changes (EMCs) are conditions frequently overlooked and misdiagnosed. The aim of this review is to update current issues and provide a classification with a practical clinicopathological approach. Hormonal or irritative stimuli are the main inducing factors of EMCs, although some metaplasias have a mutational origin. EMCs vary from reactive, degenerative lesions to those able to associate with malignancy or those having a preneoplastic potential. The most common types of EMCs are ciliated tubal metaplasia (CTM) and mucinous metaplasia (MM), which occur in simple and complex glands, and possibly these architectural changes hold the same prognostic significance as they do in hyperplastic endometrioid lesions. Immunohistochemically, CTM is positive for LhS28, bcl-2, PAX2 and p16

Context.—The field of ovarian germ cell tumors (OGCTs) has remained relatively unchanged in the last 2 decades. However, the introduction of new stem cell pluripotency markers has provided a new understanding into the identification and taxonomy of OGCT types. New data have provided new insights into unusual teratoma-associated autoimmune disorders and the origin of gliomatosis peritonei. Objective.—To review the impact of new pluripotency markers in the diagnosis of malignant OGCT (MOGCT) and analyze new nomenclature proposals and clinicopathologic entities. Data Sources.—Ovarian germ cell tumors from routine material and expert consultation files at San Cecilio University Hospital, Granada, Spain, and the relevant literature were reviewed. Conclusions.—Although a correct diagnosis of MOGCT can often be made with histologic and classic immunohistochemical studies, the new immunohistochemical pluripotency markers give higher diagnostic accuracy. Germ cell tumors represent a caricature of the phases of normal embryonic differentiation from primordial germ and stem cells to extraembryonal and somatic tissue differentiation. Since every stage of differentiation and its related tumor type exhibit characteristic markers, the analysis of their expression facilitates tumor typing, thus complementing the use of classic antibodies. They also allow a more precise evaluation of the degree of immaturity in teratoma. The new term, primitive endodermal tumors, simplifies the understanding of the complex histology of the yolk sac tumor group, as this terminology encompasses its multiple endodermal differentiations. Recently described autoimmune encephalitis due to antibodies against the N-methyl-d-aspartate receptor has become the most frequent autoimmune disorder associated with ovarian teratoma.

Purpose:To analyze immunohistochemically morules in endometrioid lesions to show that CD10 is a sensitive marker for morular metaplasia. Experimental Design: Immunohistochemical analysis of 53 instances of morular metaplasia comprising 1 cyclic endometrium and 52 endometrioid lesions associated with focal glandular complexity corresponding to 9 polyps, 4 atypical polypoid adenomyomas, 24 complex endometrial hyperplasias (18 with and 6 without atypia), 12 grade 1 endometrioid adenocarcinomas in early clinical stages of both uterus and ovary, and three ovarian adenofibromas. Immunohistochemistry in paraffin sections was done for CD10, h-catenin, estrogen and progesterone receptors, and cytokeratins 5-6, 7, 8, 13, 18, 19, 20, and 34h-E12. Results: Morules were negative for estrogen and progesterone receptors and had h-cateninp ositive nuclei. Cytokeratins 8, 18, 19 were positive; cytokeratins 7 and 20 were negative; and cytokeratins 5-6, 13, and 34h-E12 were weakly positive. All cases revealed strongly positive membranous CD10 staining in morules, which was absent in glands. CD10 positivity allowed easy identification of morules at low power in various types of surgical specimens and in curettings. CD10 also highlighted early morular metaplasia in glandular epithelium. In cases associated with squamous, keratinizing metaplasia, CD10 discriminated between both types of metaplasia. Conclusions: CD10 staining represents a useful marker of morules in endometrioid neoplasms of the female genital tract, permitting identification of lesions usually associated with an attenuated malignancy. Considering the immunohistochemical and genetic similarities of morules in tumors of different organs, it is likely that this marker may be also useful to diagnose morular metaplasia in similar neoplasms of extragenital locations.Morules (1) are nodular structures found in endometrial-type glands formed by a peculiar metaplastic non-keratinizing squamoid epithelium (2). Morphologically similar structures have also been described in neoplastic lesions in other anatomic sites, such as thyroid (3), lung (4, 5), stomach (6), pancreas (7), and colon (8).In both eutopic and ectopic endometrioid tissues, morules are almost invariably associated with the glandular architectural complexity of premalignant and low-grade glandular malignant lesions but are absent in high-grade ones. Thus, it can be said that the presence of morules in the endometrium relates well with an attenuated malignancy.This study deals with the immunohistochemical findings in a series of 53 cases of morular metaplasia from both uterus and ovary, showing for the first time that CD10 staining is a marker of morules, allowing its easy identification in various endometrioid lesions. Materials and MethodsA total of 53 cases of endometrioid morular metaplasia were collected from the files of the

No abstract