Mini-symposium: Gynaecological pathology
Diagnostic dilemmas and potential pitfalls in the evaluation of endometrial adenocarcinoma

https://doi.org/10.1016/j.mpdhp.2017.05.004Get rights and content

Abstract

Endometrial adenocarcinoma is the most common malignancy of the gynaecologic tract, and therefore one of the most commonly encountered surgical pathology specimens. Accurate diagnosis, grading and staging are necessary to direct therapy for this common disease. Evaluation of these cases is usually straightforward. Some cases, however, may be complicated by a variety of issues such as difficulty assessing depth of invasion; difficulty assessing cervical involvement; possibility of synchronous ovarian primaries; evaluation of lymphovascular space invasion; difficulties with FIGO grade (especially in the company of altered differentiation); and subtle patterns of myoinvasion. The purpose of this review is to emphasize these problematic areas and offer straightforward guidelines to apply when these situations are encountered. Proper recognition of these diagnostic challenges will hopefully improve grading and staging accuracy, and subsequently therapy, for the multitudes of women affected by this disease.

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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    © 2017 Published by Elsevier Ltd.