An analysis of two versus three grades for endometrial carcinoma

The amount of preoperative endometrial tissue surface in relation to final endometrial cancer classification

OBJECTIVE

To evaluate whether the amount of preoperative endometrial tissue surface is related to the degree of concordance with final low- and high-grade endometrial cancer (EC). In addition, to determine whether discordance is influenced by sampling method and impacts outcome.

METHODS

A retrospective cohort study within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC). Surface of preoperative endometrial tissue samples was digitally calculated using ImageJ. Tumor samples were classified into low-grade (grade 1-2 endometrioid EC (EEC)) and high-grade (grade 3 EEC + non-endometroid EC).

RESULTS

The study cohort included 573 tumor samples. Overall concordance between pre- and postoperative diagnosis was 60.0%, and 88.8% when classified into low- and high-grade EC. Upgrading (preoperative low-grade, postoperative high-grade EC) was found in 7.8% and downgrading (preoperative high-grade, postoperative low-grade EC) in 26.7%. The median endometrial tissue surface was significantly lower in concordant diagnoses when compared to discordant diagnoses, respectively 18.7 mm2 and 23.5 mm2 (P = 0.022). Sampling method did not influence the concordance in tumor classification. Patients with preoperative high-grade and postoperative low-grade showed significant lower DSS compared to patients with concordant low-grade EC (P = 0.039).

CONCLUSION

The amount of preoperative endometrial tissue surface was inversely related to the degree of concordance with final tumor low- and high-grade. Obtaining higher amount of preoperative endometrial tissue surface does not increase the concordance between pre- and postoperative low- and high-grade diagnosis in EC. Awareness of clinically relevant down- and upgrading is crucial to reduce subsequent over- or undertreatment with impact on outcome.

Data Set for the Reporting of Endometrial Cancer: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

Endometrial cancer is one of the most common cancers among women. The International Collaboration on Cancer Reporting (ICCR) developed a standardized endometrial cancer data set in 2011, which provided detailed recommendations for the reporting of resection specimens of these neoplasms. A new data set has been developed, which incorporates the updated 2020 World Health Organization Classification of Female Genital Tumors, the Cancer Genome Atlas (TCGA) molecular classification of endometrial cancers, and other major advances in endometrial cancer reporting, all of which necessitated a major revision of the data set. This updated data set has been produced by a panel of expert pathologists and an expert clinician and has been subject to international open consultation. The data set includes core elements which are unanimously agreed upon as essential for cancer diagnosis, clinical management, staging, or prognosis and noncore elements which are clinically important, but not essential. Explanatory notes are provided for each element. Adoption of this updated data set will result in improvements in endometrial cancer patient care.

Risk Stratification of Endometrial Cancer Patients: FIGO Stage, Biomarkers and Molecular Classification

Endometrial cancer (EC) is the most common gynaecologic malignancy in developed countries. The main challenge in EC management is to correctly estimate the risk of metastases at diagnosis and the risk to develop recurrences in the future. Risk stratification determines the need for surgical staging and adjuvant treatment. Detection of occult, microscopic metastases upstages patients, provides important prognostic information and guides adjuvant treatment. The molecular classification subdivides EC into four prognostic subgroups: POLE ultramutated; mismatch repair deficient (MMRd); nonspecific molecular profile (NSMP); and TP53 mutated (p53abn). How surgical staging should be adjusted based on preoperative molecular profiling is currently unknown. Moreover, little is known whether and how other known prognostic biomarkers affect prognosis prediction independent of or in addition to these molecular subgroups. This review summarizes the factors incorporated in surgical staging (i.e., peritoneal washing, lymph node dissection, omentectomy and peritoneal biopsies), and its impact on prognosis and adjuvant treatment decisions in an era of molecular classification of EC. Moreover, the relation between FIGO stage and molecular classification is evaluated including the current gaps in knowledge and future perspectives.

Prognosis Trend of Grade 2 Endometrioid Endometrial Carcinoma: Toward Grade 1 or 3?

Although the prognostic significance of grade in endometrial cancer is well known, grade 2 cases have not been evaluated separately in most of the previous studies. In this study, we aim to investigate whether the oncologic outcomes of grade 2 endometrioid endometrial carcinomas trend towards grade 1 or 3 tumors. Patients' records and pathological reports were reviewed retrospectively and eligible patients with endometrioid endometrial carcinoma were determined and distributed into 3 groups according to their 1988 International Federation of Gynecology and Obstetrics (FIGO) grade. Groups' characteristics and oncologic outcomes were compared. Differences between grades were tested with z-test and adjusted by Bonferroni method. Kaplan-Meier method was performed for the survival analysis. In total, 776 patients of endometrioid endometrial carcinoma were included in this study. Mean follow-up time was 52 ± 14 months. Patients' mean age was 56.3 ± 10.8 years. Even though grade 2 endometrioid endometrial carcinomas were different from both grade 1 and 3 in terms of the pathological features, survival analyses demonstrated that their oncologic outcomes trended towards grade 1. The grade was determined as an independent prognostic factor for overall survival (OS). The interobserver reproducibility will be improved among pathologists by combining FIGO grade 1 and 2 endometrioid endometrial carcinomas, while prognosis prediction is not likely to be affected.

Prognostic significance of solid growth in endometrioid endometrial adenocarcinoma

BACKGROUND

Endometrioid endometrial cancer is the most common histological subtype of endometrial adenocarcinoma. In the FIGO grading scheme, both architectural and nuclear grade are taken into consideration. However, the specific impact of solid growth alone on endometrioid endometrial adenocarcinoma outcome is not well documented. We sought to assess the degree of impact of solid growth on lymphovascular space invasion (LVSI), myometrial invasion, tumor size, FIGO stage, lymph node metastasis (LNM), relapse-free survival (RFS) and disease-specific survival (DSS).

METHODS

Paraffin blocks of 269 patients treated for endometrioid endometrial cancer were retrospectively analyzed with morphometry for solid growth percentages.

RESULTS

A statistically significant cut-off value of 1% solid growth was found for predicting LNM and advanced stage (III or IV), myometrial invasion and LVSI (p < 0.001) and a cut-off value of 8% was found for predicting adverse survival outcome (p < 0.001). The mean DSS was significantly higher in patients with < 6% solid growth compared to patients with 6-50%, 51-75% and > 75% solid growth (p < 0.001). Although, the mean RFS and DSS were lowest in patients with 51-75% solid growth, this did not reach statistical significance in comparison to 6-50% and > 75% (p > 0.05).

CONCLUSION

Although > 75% solid growth was most significantly associated with many of the adverse prognostic factors, this subset did not provide prognostic superiority in predicting adverse survival when compared to subsets within 6-75% solid growth. In conclusion, although no statistically significant difference in survival was found among subdivisions of architectural grades 2 and 3, solid growth, especially ≥ 8%, appeared to be an independent prognostic factor for survival in patients with early-stage endometrioid endometrial cancer.

Endometrial Carcinoma Diagnosis: Use of FIGO Grading and Genomic Subcategories in Clinical Practice: Recommendations of the International Society of Gynecological Pathologists

In this review, we sought to address 2 important issues in the diagnosis of endometrial carcinoma: how to grade endometrial endometrioid carcinomas and how to incorporate the 4 genomic subcategories of endometrial carcinoma, as identified through The Cancer Genome Atlas, into clinical practice. The current International Federation of Gynecology and Obstetrics grading scheme provides prognostic information that can be used to guide the extent of surgery and use of adjuvant chemotherapy or radiation therapy. We recommend moving toward a binary scheme to grade endometrial endometrioid carcinomas by considering International Federation of Gynecology and Obstetrics defined grades 1 and 2 tumors as "low grade" and grade 3 tumors as "high grade." The current evidence base does not support the use of a 3-tiered grading system, although this is considered standard by International Federation of Gynecology and Obstetrics, the American College of Obstetricians and Gynecologists, and the College of American Pathologists. As for the 4 genomic subtypes of endometrial carcinoma (copy number low/p53 wild-type, copy number high/p53 abnormal, polymerase E mutant, and mismatch repair deficient), which only recently have been identified, there is accumulating evidence showing these categories can be reproducibly diagnosed and accurately assessed based on biopsy/curettage specimens as well as hysterectomy specimens. Furthermore, this subclassification system can be adapted for current clinical practice and is of prognostic significance independent of conventional variables used for risk assessment in patients with endometrial carcinoma (eg, stage). It is too soon to recommend the routine use of genomic classification in this setting; however, with further evidence, this system may become the basis for the subclassification of all endometrial carcinomas, supplanting (partially or completely) histotype, and grade. These recommendations were developed from the International Society of Gynecological Pathologists Endometrial Carcinoma project.

[Grading of gynecological tumors : Current aspects]

Histopathological assessment of the tumor grade and cell type is central to the management and prognosis of various gynecological malignancies. Conventional grading systems for squamous carcinomas and adenocarcinomas of the vulva, vagina and cervix are poorly defined. For endometrioid tumors of the female genital tract as well as for mucinous endometrial, ovarian and seromucinous ovarian carcinomas, the 3‑tiered FIGO grading system is recommended. For uterine neuroendocrine tumors the grading system of the gastrointestinal counterparts has been adopted. Uterine leiomyosarcomas are not graded. Endometrial stromal sarcomas are divided into low and high grades, based on cellular morphology, immunohistochemical and molecular findings. A chemotherapy response score was established for chemotherapeutically treated high-grade serous pelvic cancer. For non-epithelial ovarian malignancies, only Sertoli-Leydig cell tumors and immature teratomas are graded. At this time molecular profiling has no impact on the grading of tumors of the female genital tract.

Combined Oral Medroxyprogesterone/Levonorgestrel-Intrauterine System Treatment for Women With Grade 2 Stage IA Endometrial Cancer

Objective

The aim of this study was to evaluate the oncologic and pregnancy outcomes of combined oral medroxyprogesterone acetate (MPA)/levonorgestrel-intrauterine system (LNG-IUS) treatment in young women with grade 2–differentiated stage IA endometrial adenocarcinoma who wish to preserve fertility.

Methods

We retrospectively reviewed the medical records of patients with grade 2 stage IA endometrial adenocarcinoma who had received fertility-sparing treatment at CHA Gangnam Medical Center between 2011 and 2015. All of the patients were treated with combined oral MPA (500 mg/d)/LNG-IUS, and follow-up dilatation and curettage were performed every 3 months.

Results

A total of 5 patients were included in the study. The mean age was 30.4 ± 5.3 years (range, 25–39 years). After a mean treatment duration of 11.0 ± 6.2 months (range, 6–18 months), complete response (CR) was shown in 3 of the 5 patients, with partial response (PR) in the other 2 patients. One case of recurrence was reported 14 months after achieving CR. This patient was treated again with combined oral MPA/LNG-IUS and achieved CR by 6 months. The average follow-up period was 44.4 ± 26.2 months (range, 12–71 months). There were no cases of progressive disease. No treatment-related complications arose.

Conclusions

Combined oral MPA/LNG-IUS treatment is considered to be a reasonably effective fertility-sparing treatment of grade 2 stage IA endometrial cancer. Although our results are encouraging, it is preliminary and should be considered with experienced oncologists in well-defined protocol and with close follow-up.

Further insight into prognostic factors in endometrial cancer: the new serum biomarker HE4

INTRODUCTION

Endometrial cancer (EC) is one of the most common gynecological cancer worldwide. To date, no good markers are routinely used in clinical practice for prognosis and monitoring. Areas covered: During the last years, an increasing interest in literature has been growing on HE4 (Human epididimis 4). Therefore, we aimed to gather all the evidence reported in literature analysing the potential prognostic value of HE4, compared to the well know tumor's features (histological type and grade, stage of disease, depth of myometrial invasion, lymphovascular space involvement and cervical involvement). Expert commentary: The analysis of data suggests that HE4 seems to have a good performance in prognosis and monitoring of the disease, helping to schedule the appropriste timing of imaging and surgery in a more individualized fashion. However, these findings surely require a validation in a larger cohorts of patients. Probably, in the next five years, prospective randomized trials will be performed to confirm the prognostic role of HE4 in EC and to find a tailored EC management strategy.

Cytological scoring and prognosis of poorly differentiated endometrioid adenocarcinoma

OBJECTIVE

Histopathological variation has been demonstrated in grade 3 endometrioid adenocarcinomas. We attempted to evaluate the clinicopathological features of grade 3 tumors by endometrial cytological features using a scoring system.

STUDY DESIGN

Twenty-one endometrial cytological samples were evaluated using 5 cytological features: rates of cluster formation in tumor cells; nuclear pleomorphism; nuclear dimension; size of nucleoli, and chromatin structure and distribution. The relationships between cytological scores and clinicopathological factors or prognosis were investigated.

RESULTS

The median cytological score was 6 (range 4-14); therefore, samples with scores of 4-5 were defined as having low scores, while those with scores of 6-14 were defined as high scores. The accuracy of the cytological diagnosis for grade 3 tumors in the high score group (8/10 patients, 80.0%) was significantly higher than that of the low score group (2/11 patients, 18.2%; p=0.009). Significant relationships between cytological scores and lymph node metastases or positive peritoneal cytology were observed (p=0.03 and 0.035, respectively). The overall survival rate was significantly worse in the high score group (30.0%) than the low score group (88.9%; p=0.02).

CONCLUSIONS

Grade 3 endometrioid adenocarcinomas varied in cytological features; according to the scoring system used, high scores were associated with worse clinicopathological factors and poorer prognosis than low scores.

The pattern of myometrial invasion as a predictor of lymph node metastasis or extrauterine disease in low-grade endometrial carcinoma

The purpose of this study was to examine predictors of lymph node (LN) metastases or extrauterine disease (ED) in low-grade (FIGO grade 1 or 2) endometrioid carcinoma (LGEC) in a multi-institutional setting. For LGEC with and without LN metastasis or ED, each of the 9 participating institutions evaluated patients' age, tumor size, myometrial invasion (MI), FIGO grade, % solid component, the presence or absence of papillary architecture, microcystic, elongated, and fragmented glands (MELF), single-cell/cell-cluster invasion (SCI), lymphovascular invasion (LVI), lower uterine segment (LUS) and cervical stromal (CX) involvement, and numbers of pelvic and para-aortic LNs sampled. A total of 304 cases were reviewed: LN(+) or ED(+), 96; LN(-)/ED(-), 208. Patients' ages ranged from 23 to 91 years (median 61 y). Table 1 summarizes the histopathologic variables that were noted for the LN(+) or ED(+) group: tumor size ≥2 cm, 93/96 (97%); MI>50%, 54/96 (56%); MELF, 67/96 (70%); SCI, 33/96 (34%); LVI, 79/96 (82%); >20% solid, 65/96 (68%); papillary architecture present, 68/96 (72%); LUS involved, 64/96 (67%); and CX involved, 41/96 (43%). For the LN(-)/ED(-) group, the results were as follows: tumor size ≥2 cm, 152/208 (73%); MI>50%, 56/208 (27%); MELF, 79/208 (38%); SCI, 19/208 (9%); LVI, 56/208 (27%); >20% solid, 160/208 (77%); papillary architecture present, 122/208 (59%); LUS involved, 77/208 (37%); CX involved, 24/208 (12%). There was no evidence of a difference in the number of pelvic or para-aortic LNs sampled between groups (P=0.9 and 0.1, respectively). After multivariate analysis, the depth of MI, CX involvement, LVI, and SCI emerged as significant predictors of advanced-stage disease. Although univariate analysis pointed to LUS involvement, MELF pattern of invasion, and papillary architecture as possible predictors of advanced-stage disease, these were not shown to be significant by multivariate analysis. This study validates MI, CX involvement, and LVI as significant predictors of LN(+) or ED(+). The association of SCI pattern with advanced-stage LGEC is a novel finding.

Problematic issues in the staging of endometrial, cervical and vulval carcinomas

The International Federation of Gynecology and Obstetrics (FIGO) staging of tumours of the uterine corpus, cervix and vulva was revised in 2009. The greatest impact of the revised staging was on carcinomas of the uterine corpus. Uterine sarcomas are now staged separately. Changes to the staging system for vulvar carcinomas largely reflect the significance of lymph node status. Only minor amendments have been introduced for cervical carcinomas, which remain the only gynaecological tumours to be staged clinically. These revisions, based on recent evidence, require careful, more detailed assessment of several histological parameters at each anatomical site. The present review deals with the evidence and rationale underpinning the revisions, and includes practical guidance on tumour staging. This covers the assessment and measurement of myoinvasion and evaluation of cervical, parametrial, serosal and vaginal involvement in carcinomas of the uterine corpus; the identification and accurate measurement of stromal invasion in cervical and vulvar carcinomas; the assessment of unusual variants of carcinoma at each of these sites; and the assessment of lymph node involvement.

Interobserver agreement for endometrial cancer characteristics evaluated on biopsy material

A shift toward a disease-based therapy designed according to patterns of failure and likelihood of nodal involvement predicted by pathologic determinants has recently led to considering a selective approach to lymphadenectomy for endometrial cancer. Therefore, it became critical to examine reproducibility of diagnosing the key determinants of risk, on preoperative endometrial tissue samples as well as the concordance between preoperative and postresection specimens. Six gynaecologic pathologists assessed 105 consecutive endometrial biopsies originally reported as positive for endometrial cancer for cell type (endometrioid versus nonendometrioid), tumor grade (FIGO 3-tiered and 2-tiered), nuclear grade, and risk category (low risk defined as endometrioid histology, grade 1 + 2 and nuclear grade <3). Interrater agreement levels were substantial for identification of nonendometrioid histology (κ = 0.63; SE = 0.025), high tumor grade (κ = 0.64; SE = 0.025), and risk category (κ = 0.66; SE = 0.025). The overall agreement was fair for nuclear grade (κ = 0.21; SE = 0.025). There is agreement amongst pathologists in identifying high-risk pathologic determinants on endometrial cancer biopsies, and these highly correlate with postresection specimens. This is ascertainment prerequisite adaptation of the paradigm shift in surgical staging of patients with endometrial cancer.

Prognosis and Reproducibility of New and Existing Binary Grading Systems for Endometrial Carcinoma Compared to FIGO Grading in Hysterectomy Specimens

Background:

The current International Federation of Gynecology and Obstetrics (FIGO) grade in endometrial carcinomas requires the evaluation of histologic features with proven prognostic value but with questionable reproducibility. This study tests the prognostic power and reproducibility of a new binary grading system.

Study Design:

Specimens from 254 hysterectomies were graded according to the new 3- and 2-tiered FIGO grading systems described by Alkushi et al. The selected morphologic parameters for the new grading system included the presence of predominant solid or papillary architecture pattern, severe nuclear atypia, tumor necrosis, and vascular invasion. The Cox proportional hazards and κ statistics were used for comparisons.

Results:

On multivariate analysis, and looking at all tumor cell types, the 4 tested grading systems were independent predictors of survival, with the 3-tiered FIGO grading system being the most predictive (P = 0.005). In the subset of endometrioid tumors, the 3- and 2-tiered FIGO grading systems and the new grading system retained their statistical significance as predictors of survival (P = 0.004, P = 0.03, and P = 0.007, respectively), whereas the grading system of Alkushi et al did not (P = 0.1). In nonendometrioid tumors, the new grading system proved to be the best predictor of survival, reaching near statistical significance (P = 0.06). The new grading system had acceptable intraobserver and interobserver reproducibility assessment (κ = 0.87 and κ = 0.45, respectively).

Conclusion:

The 3-tiered FIGO grading system retained its superior prognostic power. However, available binary grading systems remain an attractive option by being highly reproducible and by eliminating the clinical ambiguity of intermediate grades of disease.

Atypical Endometrial Hyperplasia and Well Differentiated Endometrioid Adenocarcinoma of the Uterine Corpus

The distinction between atypical endometrial hyperplasia and well differentiated adenocarcinoma of the endometrium is one of the more difficult differential diagnoses in gynecologic pathology. Different pathologists apply different histologic criteria, often with different individual thresholds for atypical endometrial hyperplasia and grade 1 adenocarcinoma. While some classifications are based on a series of molecular genetic alterations (which may or may not translate into biologically or clinically relevant risk lesions), almost all current diagnostic criteria use a series of histologic features - usually a combination of architecture and cytology - for diagnosing atypical hyperplasia and adenocarcinoma. This article presents evidence-based histologic criteria for atypical endometrial hyperplasia and low grade endometrial carcinoma (both FIGO grade 1 and 2) with emphasis on common and not so common histologic mimics. Grade 3 endometrioid carcinoma is discussed in the Oliva and Soslow article in this publication.

Endometrial carcinoma: controversies in histopathological assessment of grade and tumour cell type

Histopathological assessment of tumour grade and cell type is central to the management of endometrial carcinoma, guiding the extent of surgery and the use of adjuvant radiation therapy and chemotherapy. Endometrioid carcinomas are usually low grade but high-grade examples are encountered, and they have a significantly worse prognosis, similar to that of high-grade subtypes such as serous and clear cell carcinoma. This article reviews the various grading systems that have been proposed for use with endometrioid endometrial carcinoma, and discusses the recent progress in cell type assignment, including the use of immunohistochemistry as a diagnostic adjunct.

FIGO staging of endometrial adenocarcinoma: a critical review and proposal

The optimal staging of tumors would reflect their biology and patterns of spread, permit accurate prognostication, and facilitate therapeutic decision-making. The last revision of the International Federation of Obstetricians and Gynecologists (FIGO) staging of uterine corpus tumors was in 1988, and it represented the transition from a clinical to a surgico-pathologic system. With 20 years of experience, we can now review the accuracy, reproducibility, and utility of this system. Pathologists are in a unique position to study each of these characteristics, comment on their ability to apply the criteria in daily practice, and offer suggestions to further improve the FIGO system. This paper selectively reviews some of the more problematic aspects of the current FIGO system, including the following: the distinction of tumors confined to the endometrium from those which are superficially myoinvasive; the method and utility of histologic grading of endometrial adenocarcinoma; the utility and reproducibility of the diagnosis of cervical epithelial and stromal invasion; the striking heterogeneity within and among stage III A, B, and C tumors and their differing prognostic significance. It concludes with recommendations for changes in a future revision of the FIGO staging of endometrial carcinoma.

Should Preoperative Pathology Be Used to Select Patients for Surgical Staging in Endometrial Cancer?

Introduction:

The decision to offer surgical staging in endometrial cancer is often based on preoperative histology and grade from endometrial biopsy or dilatation and curettage. The primary objective of this study was to evaluate the concordance between preoperative and final pathology from a population-based study of endometrial cancer to address whether preoperative biopsy is a reliable determinant in selecting patients for surgical staging.

Methods:

Retrospective cohort study in Ontario, Canada, from 1996 to 2000. The study included all women with a preoperative diagnosis of endometrioid adenocarcinoma on endometrial biopsy or dilatation and curettage, followed by definitive surgery. All other histological types were excluded. Surgical staging rates were compared according to preoperative pathology. Primary outcome measure was the concordance between preoperative and final pathology, expressed as a Spearman correlation coefficient (ρ). A multivariable logistic regression estimated the effects of demographic variables and grade on our outcome measure.

Results:

There were 1804 evaluable cases in this study. For preoperative grades 1, 2, and 3 endometrioid adenocarcinoma, surgical staging rates were 9.1%, 13.7%, and 25.6%, respectively. Concordance rates with final pathology were 73%, 52%, and 53%, respectively. There was only moderate concordance between preoperative and final pathology (ρ = 0.52). There was no significant difference in concordance rates according to age, year, or hospital volume, but lower concordance rates among teaching hospitals.

Conclusion:

Preoperative biopsy has only a moderate ability to predict final pathology in endometrial cancer, and therefore, additional factors should be considered in selecting patients for a surgical staging procedure.

Reproducibility of grading systems for endometrial endometrioid carcinoma and their relation with pathologic prognostic parameters

The FIGO grading for endometrial endometrioid carcinomas is widely accepted. In 2000, a novel binary architectural grading system was suggested that divided endometrioid carcinomas into low- and high-grade tumors. We aimed to evaluate the interobserver reproducibility of the FIGO, the architectural binary, and nuclear grading systems and the correlation between these grading systems and pathologic prognostic factors for endometrial endometrioid carcinoma. Eighty-eight endometrial endometrioid carcinomas from hysterectomy specimens were reevaluated by two pathologists independently. Kappa values for the FIGO, the binary, and the nuclear grading systems were 0.65, 0.67, and 0.09, respectively. The reproducibility of the FIGO and the binary grading systems was similar and substantial. FIGO grade 1 (60.2%) patients were comparable to binary low-grade (63.6%) patients. Most of the FIGO grade 3 (83%) patients were binary high grade. FIGO grade 2 patients were distributed between binary low and high grades. The FIGO grade 1 and 2 cases judged to be of binary high grade had deep myometrial invasion, and more cases had vascular invasion in comparison with FIGO grade 1 and 2 cases judged to be of binary low grade. In uni- and multivariate analyses, both grading systems, depth of myometrial invasion, vascular invasion, cervical involvement, and stage had no effect on overall survival. But binary high grade and vascular involvement are adverse prognostic factors on recurrence-free survival. Binary high-grade patients can be assigned as high-risk patients.

Identification of prognostically relevant and reproducible subsets of endometrial adenocarcinoma based on clustering analysis of immunostaining data

Panels of immunomarkers can provide greater information than single markers, but the problem of how to optimally interpret data from multiple immunomarkers is unresolved. We examined the expression profile of 12 immunomarkers in 200 endometrial carcinomas using a tissue microarray. The outcomes of groups of patients were analyzed by using the Kaplan-Meier method, using the log-rank statistic for comparison of survival curves. Correlation between clustering results and traditional prognosticators of endometrial carcinoma was examined by either Fisher's exact test or chi2-test. Multivariate analysis was performed using a proportional hazards method (Cox regression modeling). Seven of the 12 immunomarkers studied showed prognostic significance in univariate analysis (P<0.05) and 1 marker showed a trend toward significance (P=0.06). These eight markers were used in unsupervised hierarchical clustering of the cases, and resulted in identification of three cluster groups. There was a statistically significant difference in patient survival between these cluster groups (P=0.0001). The prognostic significance of the cluster groups was independent of tumor stage and patient age on multivariate analysis (P=0.014), but was not of independent significance when either tumor grade or cell type was added to the model. The cluster group designation was strongly correlated with tumor grade, stage, and cell type (P<0.0001 for each). Interlaboratory reproducibility of subclassification of endometrial adenocarcinoma by hierarchical clustering analysis was verified by showing highly reproducible assignment of individual cases to specific cluster groups when the immunostaining was performed, interpreted, and clustered in a second laboratory (kappa=0.79, concordance rate=89.6%). Unsupervised hierarchical clustering of immunostaining data identifies prognostically relevant subsets of endometrial adenocarcinoma. Such analysis is reproducible, showing less interobserver variability than histopathological assessment of tumor cell type or grade.

[Prognostic parameters in FIGO stage I endometrial carcinoma of endometrioid type]

BACKGROUND/AIM

Endometrial carcinoma is the most common malignant neoplasm of the female genital tract in developed countries. Endometrioid carcinoma represents about three-fourths of all endometrial carcinoma. The aim of this study was to examine pathologic parameters, age, and the 5-year survival of the patients with FIGO stage I endometrial carcinoma of endometrioid type and to assess the prognostic utility of age, depth of myometrial invasion, hystologic type (endometrioid or variant), histologic grade, nuclear grade, and lymph-vascular space invasion.

METHODS

Age, pathologic parameters, and survival data were retrospectively collected on 236 patients with FIGO stage I endometrial carcinoma of endometrioid type. All the patients underwent hysterectomy between 1996 and 2000 and follow-up until December 2005.

RESULTS

A total of 236 patients (mean age 58.0, range 40-79) were analyzed. During the 5-year period of follow-up, 59 (25.0%) patents died from the disease. An univariate analysis revealed that age, depth of myometrial invasion, histologic grade, nuclear grade, and lymph-vascular space invasion were associated significantly with the 5-year survival of the patients. A multivariate analysis revealed that age, lymph-vascular space invasion, and depth of myometrial invasion were associated significantly with the 5-year survival.

CONCLUSION

Age, lymph-vascular space invasion, and depth of myometrial invasion are independent prognostic parameters for the 5-year survival of the patients with FIGO stage I endometrial carcinoma of endometrioid type.

Definitive radiotherapy in the management of isolated vaginal recurrences of endometrial cancer

PURPOSE

The aim of our study was to assess prognostic factors and overall survival after salvage radiotherapy for patients who had endometrial carcinoma and who experienced an isolated vaginal recurrence.

METHODS AND MATERIALS

We reviewed the records of 50 patients treated at our institution between 1967 and 2003 for an isolated vaginal recurrence of endometrial carcinoma. Initial treatment for endometrial carcinoma was definitive surgery in 49 patients and definitive radiotherapy in 1 patient. The median time from initial diagnosis of endometrial carcinoma to recurrence was 25 months (range, 4-179 months). Three patients (6%) received external-beam radiotherapy alone, 8 patients (16%) received brachytherapy only, and 39 patients (78%) received combined external-beam radiation therapy and brachytherapy. Median dose of radiation to the recurrence was 60 Gy (range, 16-85 Gy). Overall survival was calculated by the Kaplan-Meier method. Endpoints were measured from the date of diagnosis of the vaginal recurrence. Median follow-up of survivors after recurrence was 53 months (range, 8-159 months).

RESULTS

The 5-year and 10-year disease-free and overall survivals were 68% and 55%, and 53% and 40%, respectively. On multivariate analysis, age (p = 0.0242), Grade 1 or 2 vs. Grade 3 tumor (p = 0.002), and size of recurrence (p < 0.001) were significant predictors of overall survival. All patients who had Grade 3 disease were dead by 3.6 years from the time of recurrence. Five patients experienced a Grade 3 or 4 complication.

CONCLUSIONS

Patients treated with radiotherapy for an isolated vaginal recurrence can be cured in over 50% the cases. Radiotherapy is well tolerated, with a low risk of complications. Factors predictive of overall survival include tumor grade, patient age at recurrence, and tumor size.

Description of a Novel System for Grading of Endometrial Carcinoma and Comparison With Existing Grading Systems

The most widely used system for grading of endometrial carcinoma is the International Federation of Gynecology and Obstetrics (FIGO) grading system. This grading system requires evaluation of histologic features that are difficult to assess reproducibly. Two hundred and two cases of endometrial carcinoma, treated by hysterectomy, were retrieved from the archives of Vancouver General Hospital (1983-1998). For each tumor, the architectural pattern, nuclear grade, and mitotic index were assessed. The tumor architectural pattern, nuclear grade, and mitotic index were significant predictors of patient outcome (P < 0.0001 for each, by univariate analysis). There were no prognostic differences between patients having predominantly solid versus papillary tumors, or tumors with mild versus moderate nuclear atypia. The tumors were then classified into high and low grade based on assessment of these three features. The presence of at least two criteria of these three: 1) predominantly papillary or solid growth pattern, 2) mitotic index > or =6/10 high power fields, or 3) severe nuclear atypia, resulted in a tumor being considered high grade. Low-grade tumors satisfied at most one of those criteria. The proposed grading system was found to be an independent predictor of patient outcome when patient survival was adjusted for FIGO stage, patient age, and tumor cell type. It also had more prognostic power than other grading systems tested when it was applied to all tumors, regardless of their cell type; however, the FIGO grading system was superior for prognostication when only carcinomas of endometrioid type were considered. With the FIGO grading system, no significant difference in survival was observed between patients with grade 1 and grade 2 tumors. Combining FIGO grades 1 and 2 results in a binary system (grades 1 and 2 vs. grade 3) that was the most prognostically significant grading system tested, with the additional advantages of being highly reproducible and familiar to practicing pathologists.

The Reproducibility of a Binary Tumor Grading System for Uterine Endometrial Endometrioid Carcinoma, Compared with FIGO System and Nuclear Grading

OBJECTIVE

A binary grading system has been proposed to assess the amount of solid growth, the pattern of invasion, and the presence of necrosis, and thereby divide endometrial endometrioid carcinomas into low- and high-grade tumors. We analyzed this system for predicting the prognosis, with respect to inter- and intraobserver reproducibility and treatment modalities.

METHODS

A total of 200 endometrial carcinomas, based on hysterectomy specimens, were graded according to the binary grading system, for comparison against The International Federation of Gynecology and Obstetrics (FIGO) system and nuclear grading.

RESULTS

Both inter- and intraobserver agreement using the binary grading system (kappa = 0.57; percent agreement: 82% and kappa = 0.62; 84%) were superior compared with the FIGO system (0.50; 60% and 0.62; 73%) and the nuclear grading (0.23; 49% and 0.43; 65%). Patients with early-stage low-grade tumors had a 98% rate for 5-year survival (5YS). Patients with early-stage high-grade tumors, and those with advanced-stage low-grade tumors, had respectively 86% to 87% rates for 5YS. But patients with advanced-stage high-grade tumors had a 49% rate for 5YS. In binary low-grade early-stage tumors, the patient outcome was better with no adjuvant therapy and chemotherapy, compared with other therapies.

CONCLUSION

A binary grading system was superior to others in permitting greater reproducibility and predicting the prognosis of endometrial cancer patients.

Endometrial adenocarcinoma: beliefs and scepticism

The incidence of endometrial adenocarcinoma is high in North America and northern Europe, and low in Asia and Africa. This variance in frequency rates occurred in the late 1970s and its real cause has remained in question since. There is a widespread belief that endometrial adenocarcinomas associated with endometrial hyperplasia have a much better prognosis than those related to endometrial atrophy. This view is, in general terms, true but only because a high proportion of tumors arising from an atrophic endometrium are of serous/papillary, clear cell, or Grade 2-3 endometrioid carcinomas, in contrast to those developing from a hyperplastic endometrium, which are nearly all G1 endometrioid adenocarcinomas. These adenocarcinomas have, however, an excellent prognosis, no matter whether they are related to hyperplasia or atrophy, and taxonomically they form a single tumor group. In this regard, it is most reasonable to separate endometrial carcinomas into low- and high-grade tumors. The first are formed solely of G1 or "authentic" endometrioid adenocarcinomas, i.e., endometrioid neoplasms composed in their entirety of glandular elements without having traces of nonsquamous solid components. The high-grade tumors are formed of both endometrioid Grade 2-3 adenocarcinomas and nonendometrioid carcinomas-all of particularly aggressive behavior. The question of grading endometrioid adenocarcinomas in a precise and reproducible way becomes obvious. It is also believed that endometrial adenocarcinomas associated with endometrial hyperplasia are estrogen-primed, while those related to endometrial atrophy are deprived of hormonal stimulation. However, as we have shown in this laboratory recently, estrogen stimulation may be very common in endometrial neoplasms developing in an atrophic endometrium. For indeed most, if not all, postmenopausal atrophic endometria harboring adenocarcinomas contain actively proliferating glands, with high Ki-67 proliferation index, high epidermal growth factor receptor (EGFR) activity, high microvessel density (MVD), and rich in estrogen and progesterone receptors (ER and PR), indicative of a continuous low-level estrogenic stimulation. That there is a number of endometrial carcinomas that tend to develop in a milieu of antiestrogenic domination, following treatment for breast carcinoma, this may well represent a form of breast-endometrial hereditary disease and, certainly, merits further investigation.

A comparison of three histological grading systems in endometrial cancer

METHODS

To compare the architectural, nuclear and International Federation of Gynecology and Obstetrics (FIGO) grading systems in endometrial cancer 70 consecutive patients with endometrial cancer were retrospectively reevaluated with three grading systems.

RESULTS

Twenty-eight (40%), 27 (38.6%) and 14 (20%) cases were reported to have different grades when architectural vs nuclear, architectural vs. FIGO and nuclear vs. FIGO grading systems were compared in evaluation, respectively. Only 3 (42.8%) of the seven died patients had grade 3 in all three grading systems. Five-year survival rates were 95.7, 80, and 78.6% for architectural grade 1, 2 and 3, respectively. Same rates were 96.7, 90.5, and 78.9% for nuclear and 96, 91.7 and 81% for FIGO grading systems, respectively.

CONCLUSIONS

Grades of the tumors often change when different grading systems are used. Postoperative treatment should be considered when at least one of the grading systems indicates poor differentiation.

Prognostic parameters of endometrial carcinoma

Endometrial carcinoma is the most common malignant tumor of the female genital tract in the Western world. Approximately 80% of cases are well- to moderately differentiated (endometrioid) adenocarcinomas, which are confined to the uterine corpus at diagnosis, and thus most can be cured. Conversely, high-grade (ie, clear cell and serous) carcinomas account for only 15% to 20% of cases and show marked nuclear atypia. These tumors usually invade the myometrium and may extend beyond the uterus at the time of hysterectomy. In addition to clinical and morphological differences, these 2 groups of endometrial carcinomas differ in their pathogenesis. Whereas prognosis in the latter group is generally poor, the pathologist's role in establishing the outcome in the former group is crucial. Furthermore, it has become progressively apparent that both groups overlap to some extent, making the dualistic model a guideline at best. Over the last 2 decades, several studies have demonstrated the prognostic importance of various key surgical and pathological parameters, including histological type, histological grade, surgical-pathological stage, depth of myometrial invasion, vascular invasion, and cervical involvement. This review presents the most important prognostic factors of endometrial carcinomas from the pathologist's viewpoint, and attempts to clarify existing conflicts in the classification and diagnosis of these tumors.

Prognostic significance and interobserver variability of histologic grading systems for endometrial carcinoma

BACKGROUND

The most widely used histologic grading system for endometrial carcinoma is the three-tiered International Federation of Gynecology and Obstetrics (FIGO) system. Although FIGO grading has significant predictive value, the reproducibility of Grade 2 is limited. Recently, a binary grading system was proposed based on the amount of solid growth, the pattern of myometrial invasion, and the presence of tumor cell necrosis. The authors analyzed and compared the prognostic significance and the interobserver variability of both grading systems and of the three criteria for the binary grading system.

METHODS

Eight hundred patients with Stage I-III endometrioid endometrial carcinoma were reviewed and graded independently by two pathologists according to the three-tiered FIGO grading system and the novel binary grading system.

RESULTS

The interobserver agreement for both systems was moderate, with 70% and 73% agreement rates for the FIGO (kappa = 0.41) and binary (kappa = 0.39) grading systems, respectively. When converting the FIGO grading system into an artificial, 2-tiered grading system (Grade 3 vs. Grades 1-2), the agreement was much better (agreement rate, 85%; kappa = 0.58). Of the 3 criteria for the binary grading system, amount of solid growth (< or = 50% vs. > 50%) had the greatest reproducibility (agreement rate, 80%; kappa = 0.50). Both the 2-tiered FIGO grading system and the binary grading system were significant predictors of local recurrence, distant recurrence, and disease-specific survival (hazard ratios [HRs]: 1.7, 2.5, and 2.6, respectively, for FIGO and 2.1, 4.1, and 3.8, respectively, for the binary grading system). The amount of solid growth also was a strong prognostic factor for these three endpoints (HRs: 2.4, 3.9, and 3.8, respectively).

CONCLUSIONS

Both the binary grading system and the FIGO grading system had strong prognostic significance. Their reproducibility, however, was limited. A simple architectural binary grading system that divided tumors into low-grade lesions and high-grade lesions based on the proportion of solid growth (< or = 50% or > 50%) had superior prognostic power and greater reproducibility.

Concordance of FIGO grade of endometrial adenocarcinomas in biopsy and hysterectomy specimens

AIMS

We compared the FIGO grade of endometrial adenocarcinomas in endometrial samples and subsequent hysterectomy specimens, between 1997 and 2000 in a general pathology department. Our aims were to assess concordance, and the influence of the sampling technique, patient age, reporting pathologist and interval between the biopsy and definitive surgery. In order that the study reflected working practice, the tumour grade given by the reporting pathologist was used whenever possible.

METHODS AND RESULTS

Endometrial samples and the subsequent hysterectomy specimens from 125 patients were studied. The comparative FIGO grades were analysed with reference to biopsy type, patient age, reporting pathologist and interval between biopsy and hysterectomy. Concordance was 45% for grade 1, 63.3% for grade 2 and 75.6% for grade 3 carcinomas, the overall concordance being 64.5%. The concordance for grade 3 tumours was significantly higher than for grade 1. The predictive accuracy was independent of biopsy type, patient age, the interval between biopsy and hysterectomy, and whether the same pathologist reported both specimens.

CONCLUSIONS

Irrespective of the sampling device used, patient age, time-lapse between biopsy and hysterectomy, or whether the same pathologist reported both specimens, the grade of endometrial adenocarcinoma often differs in the initial biopsy sample from that in the final hysterectomy specimen. This may have important implications for patient management, especially for tumours that yield low-grade biopsies.

Endometrioid carcinoma of the uterine corpus: a review of its pathology with emphasis on recent advances and problematic aspects

This review considers the pathologic features of endometrioid carcinoma of the uterine corpus, which accounts for approximately 80% of endometrial adenocarcinomas, with an emphasis on its histologic features, recent advances, and problematic aspects. In addition to typical endometrioid carcinoma, the variants of endometrioid carcinoma covered include secretory carcinoma, villoglandular endometrioid carcinoma, endometrioid carcinoma with small nonvillous papillae, endometrioid carcinomas with microglandular and sertoliform patterns, and endometrioid carcinomas with metaplastic changes. These changes include a variety of different appearances of squamous epithelia (ranging from mature and keratinizing to immature with only subtle evidence of a squamous nature), clear cells, surface changes resembling syncytial metaplasia or microglandular hyperplasia, ciliated cells, oxyphilic cells, and spindled epithelial cells (sarcomatoid carcinoma). The last is one of several variants that may cause a biphasic appearance, all of which should be distinguished from the malignant müllerian mixed tumor. Rare findings in endometrioid carcinomas include hyalinization, psammoma bodies, and foci of stromal metaplasia such as osteoid. Unusual growth patterns of endometrioid carcinomas include involvement of adenomyosis, the "diffusely" infiltrating pattern of myoinvasion, and a previously unemphasized pattern of myoinvasion with "pinched off" glands that may be cystic or have a pseudovascular appearance, often with a myxoid stromal reaction. Other aspects of endometrioid carcinoma discussed are its immunoprofile, grading, cervical involvement (including a hitherto undescribed "burrowing" pattern of extension within the cervix that can result in underdiagnosis of stage IIB disease), carcinoma arising in the lower uterine segment, carcinoma arising in polyps and adenomyomas, carcinoma in young women, tamoxifen-related carcinoma, associated ovarian endometrioid carcinoma, and peritoneal keratin granulomas. Finally, the differential diagnosis of endometrioid carcinoma is briefly considered with a section on benign mimics, including curettage-related changes, menstrual changes, adenomyosis-related problems, metaplastic changes, atypical polypoid adenomyoma, radiation atypia, and papillary proliferations, and a section on metastatic colonic carcinoma.

Long-term outcome in endometrial carcinoma favors a two- instead of a three-tiered grading system

PURPOSE

Endometrial carcinoma is the most common malignancy of the female genital tract. Recognized prognostic factors include FIGO stage, histologic grade, depth of myometrial invasion, and age. Although determination of these factors may seem clear and reproducible, the histologic grade has recently been the subject of debate. A retrospective analysis of long-term outcome and predictive factors in endometrial carcinoma was conducted, focusing on the prognostic value of tumor grade.

MATERIALS AND METHODS

The study included 253 patients with endometrial carcinoma Stages I to III, who were treated between 1984 and 1993. The histologic slides were reviewed and the prognostic value of stage, age, myometrial invasion (depth and pattern), tumor grade, and histologic subtype was analyzed. The end point was cancer-specific death; the median follow-up time was 11.7 years.

RESULTS

The actuarial 5- and 10-year cancer-specific survival rates (CSS) were 85% and 82%, respectively. Five-year vaginal and/or pelvic recurrence and distant relapse rates were 7% and 15%. In multivariate analysis, stage, pattern of myometrial invasion, tumor grade, and age were independent prognostic factors. At pathology review, a shift from Grade 2 to Grade 1 was seen in 112 of the original 144 Grade 2 (78%). There was no difference in CSS between Grade 1 and Grade 2 (94 vs. 90% for original grade and 92 vs. 95% for grade after review), whereas Grade 3 was found to be a significant adverse prognostic factor (p < 0.001).

CONCLUSIONS

The independent prognostic factors for patients with endometrial cancer were stage, pattern of myometrial invasion, tumor grade, and age. Systematic grading led to a considerable shift from Grade 2 to Grade 1. However, there was no difference in prognostic significance between Grade 1 and 2, whereas Grade 3 was a major adverse prognostic factor. A two-tiered grading system, instead of the currently used three-tiered system seems preferable, because it has a better correlation with clinical outcome and is expected to have less interobserver variability.

A binary architectural grading system for uterine endometrial endometrioid carcinoma has superior reproducibility compared with FIGO grading and identifies subsets of advance-stage tumors with favorable and unfavorable prognosis

The International Federation of Gynecology and Obstetrics (FIGO) grading of uterine endometrial endometrioid carcinoma requires evaluation of histologic features that can be difficult to assess, including recognition of small amounts of solid growth, distinction of squamous from nonsquamous solid growth, and assessment of degree of nuclear atypia. The authors describe a novel, binary architectural grading system that uses low-magnification assessment of amount of solid growth, pattern of invasion, and presence of necrosis to divide endometrioid carcinomas into low- and high-grade tumors. The authors analyzed its performance for predicting prognosis and with respect to intra- and interobserver reproducibility. A total of 141 endometrioid carcinomas from hysterectomy specimens were graded according to the FIGO system, nuclear grading, and the binary architectural system. A tumor was classified as high grade if at least two of the following three criteria were present: (1) more than 50% solid growth (without distinction of squamous from nonsquamous epithelium); (2) a diffusely infiltrative, rather than expansive, growth pattern; and (3) tumor cell necrosis. For tumors that were confined to the endometrium, only percent solid growth and necrosis were evaluated, and those with both solid growth of more than 50% and necrosis were considered high grade. All tumors were graded independently by three pathologists on two separate occasions. Both inter- and intraobserver agreement using the binary grading system (kappa = 0.65 and 0.79) were superior compared with FIGO (kappa = 0.55 and 0.67) and nuclear grading (kappa = 0.22 and 0.41). The binary grading system stratified patients into three distinct prognostic groups. Patients with stage I low-grade tumors with invasion confined to the inner half of the myometrium (stages IA and IB) had a 100% 5-year survival rate. Patients with low-grade tumors that invaded beyond the outer half of the myometrium (stage IC and stages II-IV) and those with high-grade tumors with invasion confined to the myometrium (stages IB and IC) had a 5-year survival rate of 67% to 76%. In striking contrast to patients with advance-stage low-grade tumors, patients with advance-stage high-grade tumors had a 26% 5-year survival rate. This binary grading system has advantages over FIGO and nuclear grading that permit greater interobserver and intraobserver reproducibility and should be tested in other studies of endometrial endometrioid carcinomas to validate its reproducibility and use for segregating patients into different prognostic groups.

Surgery and postoperative radiotherapy versus surgery alone for patients with stage-1 endometrial carcinoma: multicentre randomised trial. PORTEC Study Group. Post Operative Radiation Therapy in Endometrial Carcinoma

BACKGROUND

Postoperative radiotherapy for International Federation of Gynaecology and Obstetrics (FIGO) stage-1 endometrial carcinoma is a subject of controversy due to the low relapse rate and the lack of data from randomised trials. We did a multicentre prospective randomised trial to find whether postoperative pelvic radiotherapy improves locoregional control and survival for patients with stage-1 endometrial carcinoma.

METHODS

Patients with stage-1 endometrial carcinoma (grade 1 with deep [> or =50%] myometrial invasion, grade 2 with any invasion, or grade 3 with superficial [<50%] invasion) were enrolled. After total abdominal hysterectomy and bilateral salpingo-oophorectomy, without lymphadenectomy, 715 patients from 19 radiation oncology centres were randomised to pelvic radiotherapy (46 Gy) or no further treatment. The primary study endpoints were locoregional recurrence and death, with treatment-related morbidity and survival after relapse as secondary endpoints.

FINDINGS

Analysis was done according to the intention-to-treat principle. Of the 715 patients, 714 could be evaluated. The median duration of follow-up was 52 months. 5-year actuarial locoregional recurrence rates were 4% in the radiotherapy group and 14% in the control group (p<0.001). Actuarial 5-year overall survival rates were similar in the two groups: 81% (radiotherapy) and 85% (controls), p=0.31. Endometrial-cancer-related death rates were 9% in the radiotherapy group and 6% in the control group (p=0.37). Treatment-related complications occurred in 25% of radiotherapy patients, and in 6% of the controls (p<0.0001). Two-thirds of the complications were grade 1. Grade 3-4 complications were seen in eight patients, of which seven were in the radiotherapy group (2%). 2-year survival after vaginal recurrence was 79%, in contrast to 21% after pelvic recurrence or distant metastases. Survival after relapse was significantly (p=0.02) better for patients in the control group. Multivariate analysis showed that for locoregional recurrence, radiotherapy and age below 60 years were significant favourable prognostic factors.

INTERPRETATION

Postoperative radiotherapy in stage-1 endometrial carcinoma reduces locoregional recurrence but has no impact on overall survival. Radiotherapy increases treatment-related morbidity. Postoperative radiotherapy is not indicated in patients with stage-1 endometrial carcinoma below 60 years and patients with grade-2 tumours with superficial invasion.

Problems in the differential diagnosis of endometrial hyperplasia and carcinoma

The differential diagnosis of endometrial hyperplasia and well-differentiated endometrioid adenocarcinoma is complicated not only by the resemblance of these lesions to each other, but also by their tendency to be overdiagnosed (particularly hyperplasia) on the background of polyps, endometritis, artifacts, and even normally cycling endometrium. Atypical hyperplasia may also be overdiagnosed when epithelial metaplastic changes occur in simple or complex hyperplasia without atypia. Low-grade adenocarcinomas are best recognized by architectural evidence of stromal invasion, usually in the form of stromal disappearance, desmoplasia, necrosis, or combinations of these findings between adjacent glands. Endometrioid adenocarcinomas are usually Type 1 cancers associated with manifestations of endogenous or exogenous hyperestrogenic stimulation and a favorable prognosis. Subtypes include adenocarcinomas with squamous differentiation and secretory, ciliated cell and villoglandular variants. Rules and pitfalls in the grading of endometrioid adenocarcinomas and the estimation and reporting of myometrial invasion are presented.