[Pitfalls in the histopathological diagnostics of endometrial carcinoma and its precursors : Clinically relevant differential diagnoses, avoidance of false positive diagnoses]. / Fallstricke bei der histopathologischen Diagnostik des Endometriumkarzinoms und seiner Vorstufen : Klinisch wichtige Differenzialdiagnosen, Vermeidung falsch-positiver Diagnosen.

Making an incorrect histopathological diagnosis of an endometrial lesion may lead to unwanted loss of fertility and therapy-associated morbidity; therefore, endometrial carcinomas need to be correctly typed and differentiated from hyperplastic precursors, benign lesions and artifacts. Typical diagnostic pitfalls are described in this article. Misdiagnosing endometrial lesions can be avoided by paying thorough attention to gross as well as microscopic features and by taking crucial differential diagnoses into consideration. These are, in particular, well-differentiated endometrioid adenocarcinoma of the endometrium versus atypical endometrial hyperplasia, myoinvasive endometrioid adenocarcinoma versus atypical polypoid adenomyoma and endometrioid carcinoma versus serous carcinoma of the endometrium with a predominantly glandular pattern. It is also important to consider the possibility of a false positive diagnosis of atypical endometrial hyperplasia or carcinoma in cases of biopsy-induced artifacts.

Atypical Polypoid Adenomyoma of the Uterus: An Immunohistochemical and Molecular Study of 21 Cases.

Atypical polypoid adenomyoma (APA) is an uncommon uterine lesion that commonly recurs after local excision and is occasionally associated with or precedes the development of atypical hyperplasia or endometrioid adenocarcinoma. Despite the fact that about 230 cases have been reported in the literature, only 2 studies of 6 and of 7 cases have investigated the molecular aspects; as such, molecular alterations that occur in APA remain largely unknown. We undertook a comprehensive immunohistochemical and molecular analysis of 21 cases of APA in 17 patients (including 4 recurrent/persistent lesions). The analyzed genes were PTEN and TP53 (by fluorescence in situ hybridization) and KRAS, BRAF, EGFR, and NRAS (all by polymerase chain reaction). Immunohistochemical staining was performed for PTEN, p53, mTOR, ß-catenin, HNF-1ß, and GLUT1 and for the mismatch-repair proteins MLH-1, MSH-2, MSH-6, and PMS-2. In most cases, there was nuclear expression of ß-catenin in squamous morules and expression of HNF-1ß, mTOR, and GLUT1 in the glandular component. All cases exhibited "wild-type" expression of p53. A common finding was loss of PTEN expression (6/19 cases). In 1 of these cases, loss of PTEN expression was accompanied by PTEN deletion. Mutation of the KRAS gene was found in 5/19 cases. Intact mismatch-repair protein expression was present in all cases, and TP53 abnormalities or mutations of EGFR, NRAS, or BRAF genes were not found. Given the association with atypical hyperplasia and endometrioid adenocarcinoma and the shared immunohistochemical and molecular features, we feel that, conceptually, APA is best regarded as analogous to a localized form of atypical hyperplasia.

Uterine adenomyosis: a need for uniform terminology and consensus classification.

Modern imaging techniques allow non-invasive diagnosis of adenomyosis, a relatively common disorder characterized by the presence of heterotopic endometrial glands and stroma in the myometrium with hyperplasia of the adjacent smooth muscle. The study of adenomyosis is greatly hampered by a lack of clear terminology and the absence of a consensus classification of the lesions. Any classification of adenomyosis must begin with an evaluation of the myometrium underlying the endometrium, the so-called junctional zone, since homogeneous thickening of this zone has become the standard criterion for non-invasive diagnosis. Although transvaginal sonography is useful for the detection of adenomyosis, the technique is highly operator dependent. Magnetic resonance imaging provides superior soft tissue resolution and currently represents the most accurate technique for non-invasive diagnosis. Adenomyosis represents a spectrum of lesions, ranging from increased thickness of the junctional zone to overt adenomyosis and adenomyomas, which in turn can be subclassified. It is increasingly recognized that adenomyosis is often associated with pelvic endometriosis yet the contribution of myometrial lesions to clinical symptoms, such as infertility and pain, remains poorly understood. Moreover, recent studies indicate that adenomyosis is a progressive disease that changes in appearance during the reproductive years. A consensus classification of uterine adenomyosis is urgently required.