Mini-symposium: Gynaecological pathologyDiagnostic dilemmas and potential pitfalls in the evaluation of endometrial adenocarcinoma
Introduction
Evaluation of a hysterectomy specimen in the context of endometrial carcinoma is one of the most common tasks facing surgical pathologists. The International Federation of Gynaecology and Obstetrics (FIGO) staging system uses the depth of tumour invasion and spread of tumour to adjacent structures (such as the cervix, serosa or adnexa) to determine the need for further treatment. Therefore, correct evaluation of these important features is critical. Furthermore, determination of a FIGO grade (1 through 3) provides insight into the potential aggressiveness of endometrioid tumours. The majority of cases present little problem in the determination of FIGO grade and stage; however, complicating factors do arise. The purpose of this review is to emphasize some of the more common challenges that may arise in the evaluation of hysterectomy specimens, and offer guidelines for addressing these problem areas.
Section snippets
Depth of invasion
Assessing depth of invasion in endometrial cancer can be one of the most common problems plaguing practicing pathologists. As depth of invasion is one of the most important factors influencing prognosis, accurate determination is vital in predicting outcome and further therapy. Two important “cutoffs” should be kept in mind when evaluating tumours for myometrial invasion: first, is invasion present (Stage Ia); and second, if it is present, does it extend more than 50% of the way through
Cervical involvement
Cervical involvement can be seen in up to 20–30% of hysterectomies performed for endometrial carcinoma,4, 5, 6 and it has long been considered a negative prognostic indicator. The distinction between cervical gland and stromal involvement was removed in the 2009 FIGO revision, with only cervical stromal involvement considered sufficient for classification as Stage II disease. In most cases, identifying cervical involvement is relatively straightforward, but there are a few circumstances in
Synchronous primaries vs. ovarian metastasis
Occasionally, patients may present with cancerous involvement of both the uterus and ovaries. This presentation raises the possibility of three distinct scenarios: uterine metastasis from ovary; ovarian metastasis from the uterus; or synchronous primaries. Determination of the site of origin of the tumour or tumours is vital in order to correctly stage the patient and determine the need for adjuvant therapy. Uterine metastasis to the ovaries (Stage 3) and ovarian metastasis to the uterus (Stage
Lymphovascular invasion
The presence of lymphovascular space invasion (LVI) is one of the criteria for determining high-risk disease, and may prompt the additional therapy. In most instances, the identification of LVI is straightforward. When the presence of LVI is in doubt, features that favour an interpretation as LVI include:
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the presence of fibrin admixed with the tumour cell cluster,
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smooth borders,
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clusters conforming to the shape of the vascular space and
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a change in morphology from the myoinvasive tumour, usually
FIGO grading
Classification of endometrial carcinomas is based primarily on tumour type, and can be broadly divided into Type I and Type II categories, reflecting underlying differences in the molecular pathways of tumorigenesis as well as prognosis.6 Some carcinomas are by definition high grade (Type II), including serous, clear cell and undifferentiated types, while endometrioid and mucinous types (Type I) are not. Endometrioid carcinomas, by far the most commonly encountered subtype, are graded using the
Conclusion
This review highlights five areas that may pose difficulty in the evaluation of hysterectomies for endometrial cancer. Knowledge of the potential pitfalls that may complicate assessment of depth of invasion, cervical and ovarian involvement, lymphovascular involvement, and FIGO grade can help to avoid errors in diagnosis. Awareness of these areas and their impact on grade and stage can help promote accuracy and precision in diagnosis, leading to proper, more informed treatment choices for
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