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

Association of Local and Distant Organ Metastases With MELF Pattern in Endometrial Cancer

Several types of myometrial invasion in endometrioid-type endometrial adenocarcinoma (EEC) have been identified: adenomyosis-like changes; adenoma malignum; broad front, single-cell/cell clusters; and the microcystic elongated and fragmented (MELF) pattern. This study aims to investigate the effect of the MELF pattern on recurrence type and survival rate among patients with EEC. We retrospectively reviewed the records of patients diagnosed with EEC over a 10-year period from January 2011 to January 2021. Among 108 patients with EEC, 54 had recurrence (study group), and 54 did not (control group). The MELF pattern was more common in the group with recurrence than in the group without recurrence (40.7% vs. 14.8%; P=0.002). The MELF pattern was observed in 60.0% of patients with local recurrence and 29.4% of patients with extrapelvic or distant organ metastases (P=0.027). Evaluation of 5-year disease-free survival (P=0.003) and overall survival (P=0.001) rates showed that MELF positivity was associated with decreased survival. Among patients with grade I-II EEC lacking uterine-localized myometrial invasion, the MELF pattern was less common in the nonrelapsed group than in the local relapse group (10.0% vs. 60.0%; P<0.001). The MELF pattern (odds ratio=19.4, 95% CI=1.2-31.2) was a significant independent negative predictor for local recurrence. The MELF pattern was more common in patients with recurrence, especially local recurrence. This finding suggests that the MELF pattern primarily impacts direct local invasion rather than hematogenous or lymphatic spread.

Blood Vessel Invasion Is an Independent Prognostic Factor in Endometrial Endometrioid Carcinoma Compared to Lymph Vessel Invasion and Myometrial Invasion Pattern

We studied 115 cases of EEC diagnosed on hysterectomy specimens. Double immunohistochemical staining (D2-40/CD31) was performed in all 115 cases to show LVI and BVI on the same slide. MELF pattern invasion was present in 24/115 (21%) cases. MELF-positive tumors had a higher frequency of LVI than MELF-negative tumors (58% and 23%, respectively); the frequency of BVI was twice as high in MELF-positive tumors in comparison to MELF-negative tumors (25% and 12%, respectively). These differences were significant (p ˂ 0.0001). All tumors with positive BVI also had a concomitant LVI. The presence of MELF invasion had no impact on overall survival, confirming previous studies. 5-year survival rates were almost equal in cases with negative LVSI and cases with positive isolated LVI (98% vs. 97%). However, in cases where BVI was also present, the 5-year survival rate was significantly lower, 63% (p ˂ 0.0001). Furthermore, BVI proved to be an independent prognostic factor for overall survival, disease-free survival, and recurrence in the multivariate analysis. In conclusion, MELF pattern invasion is a good predictor of lymphatic and blood vessel invasion but has no prognostic value. Our results suggest that BVI in EEC has greater clinical value than isolated LVI or myometrial invasion patterns, and the therapeutic approach should be guided by BVI presence. Therefore, we hope this study will promote the routine evaluation of BVI in the context of EEC diagnostic procedures.

Molecular Classification of Endometrial Endometrioid Carcinoma With Microcystic Elongated and Fragmented Pattern

The studies on the molecular classification of endometrioid carcinoma (EC) with microcystic, elongated, and fragmented (MELF) pattern invasion are limited. In this study, 77 cases of ECs with MELF patterns in Chinese women were collected. The molecular classification of the fifth edition of the World Health Organization was used to classify the molecular subtypes using immunohistochemistry staining (mismatch repair [MMR]-immunohistochemistry: MSH2, MSH6, MLH1, and PMS2; p53) and Sanger sequencing targeted POLE . The results showed that the prevalence of the 4 molecular subtypes in EC with MELF pattern was 6.5% (5/77) for POLE mutation, 20.8% (16/77) for MMR deficient, 11.7% (9/77) for p53-mutant, and 61.0% (47/77) for no specific molecular profile. The clinicopathological characteristics of each subtype were compared. The p53-mutant and no specific molecular profile subgroups were associated with higher International Federation of Gynecology and Obstetrics stage and International Federation of Gynecology and Obstetrics grade, deeper myometrial invasion, lymphovascular space invasion, lymph node metastasis, and absence of tumor-infiltrating lymphocytes, whereas the POLE mutation and MMR deficient subgroups were associated with lower aggressive features and prominent tumor-infiltrating lymphocytes. Progression-free survival showed that the p53-mutant and no specific molecular profile subgroups had a poorer prognosis than the POLE mutation and MMR deficient subgroups. However, lymph node metastasis was an independent factor associated with a higher risk of disease recurrence in multivariate analysis. In conclusion, ECs with MELF patterns can be divided into 4 molecular subtypes with discrepancies in aggressive clinicopathological characteristics and tumor-infiltrating lymphocytes. Molecular classification has clinical significance in a morpho-molecular approach for ECs with MELF patterns.

Risk assessment of extra-uterine involvement and prognosis in young type I endometrial carcinoma with high or moderate differentiation and less than 1/2 myometrial invasion

PURPOSE

The aim of this study was to investigate whether young patients with endometrial carcinoma can preserve adnexa and lymph nodes to improve their quality of life without compromising their prognosis.

METHODS

A total of 319 patients with type I endometrial carcinoma (high or moderate differentiation and less than 1/2 myometrial invasion) hospitalized in the First Affiliated Hospital of Zhengzhou University from May 2012 to July 2021 were included. The patients were divided into four groups: high differentiation without myometrial invasion group (G1MI-), high differentiation with superficial myometrial invasion group (G1MI+), moderate differentiation without myometrial invasion group (G2MI-), and moderate differentiation with superficial myometrial invasion group (G2MI+). Logistic regression analysis was conducted to identify risk factors for extra-uterine involvement. Kaplan-Meier method was used to draw the survival curve to compare the prognosis in subgroups and rates of extra-uterine involvement were also compared using Chi-square test or Fisher's exact test.

RESULTS

Multivariable logistic regression revealed that differentiation (HR = 14.590, 95%CI = 1.778-119.754, p = 0.013) and myometrial invasion (HR = 10.732, 95%CI = 0.912-92.780, p = 0.037) were the independent risk factors for extra-uterine involvement. The overall difference was statistically significant (p < 0.001). In the subgroups analysis, both adnexal metastasis and lymph node metastasis were statistically significant in the G2MI+ group compared with G1MI- (p = 0.007, p = 0.008). There were no significant differences in the overall survival (OS) rate and progression free survival (PFS) rate among the four subgroups (p > 0.05).

CONCLUSIONS

Surgery with adnexal preservation and without systematic lymphadenectomy could be employed for the patients who are high differentiation with less than 1/2 myometrial invasion or moderate differentiation without myometrial invasion, but not recommended to the patients with moderate differentiation and superficial myometrial invasion.

Endocervical Adenocarcinoma Showing Microcystic, Elongated, and Fragmented (MELF) Pattern of Stromal Invasion: A Single-Institutional Analysis of 10 Cases with Comprehensive Clinicopathological Analyses and Ki-67 Immunostaining

Microcystic, elongated, and fragmented (MELF) pattern of invasion has seldom been documented in endocervical adenocarcinoma (EAC). The aim of this study was to analyze the clinicopathological characteristics of EAC showing MELF pattern. We collected the clinicopathological information of 10 cases of EAC with the MELF pattern and conducted polymer-based immunostaining for Ki-67 (dilution 1:200, clone MIB-1) on these cases. Ki-67 expression was assessed using the average estimation within the hotspot method. All tumors were human papillomavirus-associated EAC with Silva pattern C. All except one tumor exceeded 3 cm in size. Five tumors involved the entire thickness of the cervical stroma, and four tumors extended into the parametrium. Lymphovascular space invasion was identified in six cases. Two patients developed metastatic recurrences in the para-aortic lymph nodes and lungs, respectively. The MELF area showed significantly lower Ki-67 labelling index than that of a conventional tumor area. We confirmed our previous observation that the MELF area displayed lower proliferative activity than the conventional tumor area of EAC. We also demonstrated that patients with EAC showing MELF pattern had several adverse clinicopathological characteristics reflecting aggressive behavior. On the other hand, since the frequencies of post-operative recurrence and disease-related mortality that occurred during the follow-up period were relatively low, further investigations are warranted to clarify the prognostic value of MELF pattern in EAC patients.

Can the microcystic, elongated and fragmented pattern of invasion influence the evaluation of the depth of myometrial invasion in low-grade endometrioid endometrial cancer using imaging techniques?

Objectives

The microcystic, elongated and fragmented pattern of invasion can be associated with an underestimation of the depth of myometrial invasion by imaging techniques. We aimed to evaluate the influence of microcystic, elongated and fragmented pattern of invasion in the diagnostic performance of transvaginal ultrasound scan and magnetic resonance imaging for the prediction of the depth of myometrial invasion in low-grade endometrioid endometrial carcinomas.

Methods

Prospective and consecutive study including all low-grade (G1-G2) endometrioid endometrial carcinomas diagnosed between October 2013 and July 2018 in a tertiary hospital. Preoperative staging was performed with transvaginal ultrasound scan and/or magnetic resonance imaging followed by surgical staging. Final histology was considered as the reference standard. Sensitivity, specificity and diagnostic accuracy for the prediction of depth of myometrial invasion was calculated for both imaging techniques. The STARD 2015 guidelines were used.

Results

A total of 136 patients were consecutively included. Transvaginal ultrasound scan was performed in 132 patients and magnetic resonance imaging in 119 patients. The diagnostic accuracy of transvaginal ultrasound scan for the prediction of depth of myometrial invasion in the microcystic, elongated and fragmented negative group (82% (95% confidence interval = 73-88)) was higher compared to the microcystic, elongated and fragmented positive group (61% (95% confidence interval = 36-83)). The diagnostic accuracy of magnetic resonance imaging was also higher in the microcystic, elongated and fragmented negative group (80% (95% confidence interval = 71-87)) compared to the microcystic, elongated and fragmented positive (47% (95% confidence interval = 21-73)).

Conclusions

In low-grade endometrioid endometrial carcinomas with a positive microcystic, elongated and fragmented pattern of invasion, the evaluation of the depth of myometrial invasion using transvaginal ultrasound scan and magnetic resonance imaging may be underestimated.

A Radiomic-Based Machine Learning Model Predicts Endometrial Cancer Recurrence Using Preoperative CT Radiomic Features: A Pilot Study

BACKGROUND

Current prognostic models lack the use of pre-operative CT images to predict recurrence in endometrial cancer (EC) patients. Our study aimed to investigate the potential of radiomic features extracted from pre-surgical CT scans to accurately predict disease-free survival (DFS) among EC patients.

METHODS

Contrast-Enhanced CT (CE-CT) scans from 81 EC cases were used to extract the radiomic features from semi-automatically contoured volumes of interest. We employed a 10-fold cross-validation approach with a 6:4 training to test set and utilized data augmentation and balancing techniques. Univariate analysis was applied for feature reduction leading to the development of three distinct machine learning (ML) models for the prediction of DFS: LASSO-Cox, CoxBoost and Random Forest (RFsrc).

RESULTS

In the training set, the ML models demonstrated AUCs ranging from 0.92 to 0.93, sensitivities from 0.96 to 1.00 and specificities from 0.77 to 0.89. In the test set, AUCs ranged from 0.86 to 0.90, sensitivities from 0.89 to 1.00 and specificities from 0.73 to 0.90. Patients classified as having a high recurrence risk prediction by ML models exhibited significantly worse DSF (p-value < 0.001) across all models.

CONCLUSIONS

Our findings demonstrate the potential of radiomics in predicting EC recurrence. While further validation studies are needed, our results underscore the promising role of radiomics in forecasting EC outcomes.

Prognostic Impact of Pathologic Features in Molecular Subgroups of Endometrial Carcinoma

The molecular characterization of endometrial carcinoma (EC) has recently been included in the ESGO/ESTRO/ESP guidelines. The study aims to evaluate the impact of integrated molecular and pathologic risk stratification in the clinical practice and the relevance of pathologic parameters in predicting prognosis in each EC molecular subgroup. ECs were classified using immunohistochemistry and next-generation sequencing into the four molecular classes: POLE mutant (POLE), mismatch repair deficient (MMRd), p53 mutant (p53abn), and no specific molecular profile (NSMP). According to the WHO algorithm, 219 ECs were subdivided into the following molecular subgroups: 7.8% POLE, 31% MMRd, 21% p53abn, 40.2% NSMP. Molecular classes as well as ESGO/ESTRO/ESP 2020 risk groups were statistically correlated with disease-free survival. Considering the impact of histopathologic features in each molecular class, stage was found to be the strongest prognostic factor in MMRd ECs, whereas in the p53abn subgroup, only lymph node status was associated with recurrent disease. Interestingly, in the NSMP tumor, several histopathologic features were correlated with recurrence: histotype, grade, stage, tumor necrosis, and substantial lymphovascular space invasion. Considering early-stage NSMP ECs, substantial lymphovascular space invasion was the only independent prognostic factor. Our study supports the prognostic importance of EC molecular classification and demonstrated the essential role of histopathologic assessment in patients' management.

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.

Microcystic, elongated and fragmented (MELF) pattern in endometrial carcinoma: clinicopathologic analysis and prognostic implications

To assess the clinical value of microcystic, elongated, and fragmented (MELF) pattern in Chinese patients with endometrial endometrioid carcinoma. A total of 189 patients with endometrial endometrioid carcinoma were retrospectively analyzed in Peking University Third Hospital from January 2017 to December 2019. We analyzed the association of MELF pattern with the histopathologic data and prognosis of the patients, while immunohistochemistry was performed. The frequency of MELF pattern was 17.99% (34/189). MELF pattern was associated significantly with tumor size, myometrial invasion, histological grade, International Federation of Gynecology and Obstetrics stages, lymphovascular space invasion, and lymph node metastasis. According to multivariate logistic regression analysis, lymphovascular space invasion [95% confidence interval 1.021-48.485, P = .048] was a significant predictor of lymph node involvement. However, MELF pattern was not a significant predictor (95% confidence interval 0.054-2.279, P = .400). Loss of expression for mismatch repair proteins was observed in 10 MELF + cases (29.41%) and 54 MELF- cases (34.84%), respectively. All patients were followed up for 36.8 ± 8.9 months (18-54 months). Only 1 patient with MELF pattern was diagnosed with vaginal recurrence 28 months after the surgery. MELF pattern was associated with adverse histologic findings in endometrial endometrioid carcinomas. However, MELF pattern was statistically not a valuable predictor of lymph node metastasis and it needs more studies to show whether MELF pattern has an impact on the prognosis of patients with endometrial endometrioid carcinoma. MELF pattern may be important for identifying those patients who need comprehensive staging surgery.

Predictability of lymph node involvement in uterus-confined endometrioid endometrial cancer by tumour size, pattern and location measured with transvaginal ultrasonography: can we save time?

We aimed to investigate whether transvaginal ultrasonography (TVUSG)-measured tumour size, pattern and location were significant predictors for lymph node metastasis in the uterus-confined endometrioid endometrial cancer (EEC) patients. A total of 213 patients with EEC were recruited and 73 of them were considered eligible and were analysed according to lymph node involvement. Tumour size, pattern and location measured by transvaginal ultrasound were recorded. Thereafter, patients were distributed according to their lymph node involvement and were compared with respect to these parameters. The patients' median age was 56 (27-80). Mean of the resected lymph nodes was 29.68 and 33.5 in lymph-node-negative and positive patients, respectively (p=.525). Tumour diameter was measured >2 cm on transvaginal ultrasound in 28 (48.3%) and 13 (86.7%) cases of the lymph node-negative and positive arms, respectively (p=.008). Transvaginal ultrasound revealed that 18 (31.0%) tumours in lymph node-negative and two (13.3%) in the node positive patients had polypoid pattern (p=.171). Seventeen (54.8%) tumours of the lymph node-negative group and three (42.9%) of the node positive group were determined in the lower uterine segment (p=.250). While tumour diameter measured with TVUSG was predictable for lymph node involvement in the uterus-confined EEC, its pattern and location were not.Impact StatementWhat is already known on this subject? In clinically early-stage endometrioid endometrial cancer (EEC), it has been recognised for decades that selective lymphadenectomy is a more acceptable strategy than the systematic lymphadenectomy, owing to the low rate of lymph node metastases in the patients. Preoperative imaging, frozen section and recently accepted lymph node concept are the prominent methods in designating appropriate candidates for lymphadenectomy. The measurement of tumour diameter or size obtained intraoperatively by frozen section assessment is one of the parameters used in MAYO criteria for selective lymphadenectomy in endometrial cancer patients.What do the results of this study add? In our study, tumour diameter measured with transvaginal ultrasonography was predictable for lymph node involvement in the uterus-confined EEC.What are the implications of these findings for clinical practice and/or further research? Transvaginal ultrasonography-measured tumour diameter can be considered in deciding to proceed with pelvic lymphadenectomy while waiting for the frozen section result. It should be remembered that this approach could be considered only in clinics using MAYO criteria for selective lymphadenectomy, and it needs to be confirmed with more prospective studies.

Microcystic elongated and fragmented (MELF) pattern of invasion: Molecular features and prognostic significance in the PORTEC-1 and -2 trials

OBJECTIVE

Microcystic, elongated fragmented (MELF) pattern of myometrial invasion is a distinct histologic feature occasionally seen in low-grade endometrial carcinomas (EC). The prognostic relevance of MELF invasion was uncertain due to conflicting data, and it had not yet appropriately been studied in the context of the molecular EC classification. We aimed to determine the relation of MELF invasion with clinicopathological and molecular characteristics, and define its prognostic relevance in early-stage low/intermediate risk EC.

METHODS

Single whole tumor slides of 979 (85.8%) out of 1141 (high)intermediate-risk EC of women who participated in the PORTEC-1/-2 trials were available for review. Clinicopathological and molecular features were compared between MELF invasion positive and negative cases. Time-to-event analyses were done by Kaplan-Meier method, log-rank tests and Cox' proportional hazards models.

RESULTS

MELF invasion was found in 128 (13.1%) cases, and associated with grade 1-2 histology, deep myometrial invasion and substantial lymph-vascular space invasion (LVSI). 85.6% of MELF invasion positive tumors were no-specific-molecular-profile (NSMP) EC. NSMP EC with MELF invasion were CTNNB1 wild type in 92.2% and KRAS mutated in 24.4% of cases. Risk of recurrence was lower for MELF invasion positive as compared to MELF invasion negative cases (4.9% vs. 12.7%, p = 0.026). However, MELF invasion had no independent impact on risk of recurrence (HR 0.65, p = 0.30) after correction for clinicopathological and molecular factors.

CONCLUSIONS

MELF invasion has no independent impact on risk of recurrence in early-stage EC, and is frequently observed in low-grade NSMP tumors. Routine assessment of MELF invasion has no clinical implications and is not recommended.

Classification Systems of Endometrial Cancer: A Comparative Study about Old and New

Endometrial cancer is the most common gynecological malignancy of the female reproductive organs. Historically it was divided into type I and type II, until 2013 when the Cancer Genome Atlas molecular classification was proposed. Here, we applied the different classification types on our endometrial cancer patient cohort in order to identify the most predictive one. We enrolled 117 endometrial cancer patients available for the study and collected the following parameters: age, body mass index, stage, menopause, Lynch syndrome status, parity, hypertension, type of localization of the lesion at hysteroscopy, type of surgery and complications, and presence of metachronous or synchronous tumors. The tumors were classified according to the European Society for Medical Oncology, Proactive Molecular Risk Classifier for Endometrial Cancer, Post-Operative Radiation Therapy in Endometrial Carcinoma, and Cancer Genome Atlas classification schemes. Our data confirmed that European Society for Medical Oncology risk was the strongest predictor of prognosis in our cohort. The parameters correlated with poor prognosis were the histotype, FIGO stage, and grade. Our study cohort shows that risk stratification should be based on the integration of histologic, clinical, and molecular parameters.

Sentinel Nodal Metastasis Detection in Endometrial Carcinoma With Microcystic, Elongated, and Fragmented (MELF) Pattern by Cytokeratin Immunostaining

OBJECTIVES

The microcystic, elongated, and fragmented (MELF) pattern of myoinvasion in endometrial carcinoma (EC) is associated with an increased risk of lymph node metastasis. Our aim is to assess the role of cytokeratin immunohistochemical (IHC) stains in detecting sentinel nodal metastasis in MELF pattern tumors.

METHODS

We recovered 19 MELF pattern EC hysterectomies with lymphadenectomy from our files. Negative nodes were subjected to cytokeratin AE1/AE3 IHC. Ten additional cases with sentinel lymph node (SLN) biopsies primarily assessed by IHC were also analyzed.

RESULTS

Of the 19 cases of EC, 6 had positive lymph nodes based on H&E-stained sections at the time of their initial diagnosis. With the addition of IHC stains, 8 previously negative cases were found to have node metastases, and 3 of these were SLNs. Among the 10 cases primarily assessed by IHC, 5 had malignant cells in their SLNs.

CONCLUSIONS

Cytokeratin IHC staining detected malignant cells in 9 of 16 cases with SLNs in our sample of women with MELF pattern of myoinvasion. Immunohistochemical stains should be routinely performed on SLNs from all MELF-positive cases to detect occult lymph node metastases and isolated tumor cells.

Patterns of Myometrial Invasion in Endometrial Adenocarcinoma with Emphasizing on Microcystic, Elongated and Fragmented (MELF) Glands Pattern: A Narrative Review of the Literature

Endometrioid endometrial adenocarcinoma (EEC) is the most common malignancy of the female genital tract. According to the 2009 FIGO staging system, the depth of myometrial invasion (MI), and tumor spread to adjacent organs or tissues are the staging criteria for endometrial carcinoma (EC). Therefore, assessment of the depth of MI is of great importance. There is a spectrum of morphological patterns of MI. Still, their number and features vary according to the scientific literature, with a certain overlap that creates difficulties and controversies in the precise assessment of MI depth. The purpose of this review is to present and discuss the most important and recent information about patterns of MI, focusing on the more aggressive and the elongated and fragmented glands (MELF) pattern in particular. Assessment of MI depth and correct staging of EC is possible only after the precise recognition of each MI pattern.

Prognostic significance of tumor budding, poorly differentiated cluster, and desmoplastic reaction in endometrioid endometrial carcinomas

AIMS

The tumor budding (TB); poorly differentiated cluster (PDC); desmoplastic reaction (DR); and microcystic, elongated, and fragmented (MELF) patterns of invasion are pathological findings at the tumor invasion front associated with epithelial-to-mesenchymal transition. This study aimed to clarify the clinical significance of the TB, PDC, DR, and MELF patterns in endometrioid endometrial carcinomas (EEC).

METHODS

Two hundred and eight cases of histologically proven EEC retrieved from the archives of the Department of Pathology, Fukui Prefectural Hospital, and diagnosed between January 2000 and August 2020 were retrospectively analyzed.

RESULTS

The TB, PDC, DR, and MELF patterns were identified in 29 (13.9%), 47 (22.6%), 45 (21.6%), and 23 (11.1%) cases, respectively. Kaplan-Meier curve analysis with log-rank test demonstrated that TB, PDC, and DR were associated with a lower progression-free survival (p = 0.010, 0.002, and <0.0001, respectively), whereas the MELF pattern did not show any association (p = 0.668). In multivariate analyses, only DR was significantly associated with lower progression-free survival (p = 0.034). Moreover, only PDC was associated with lower overall survival in univariate analysis (p = 0.018), but the association lost significance in multivariate analysis.

CONCLUSIONS

The present study revealed that the histological confirmation of TB, PDC, and DR at the tumor invasive front predicts poor prognosis in EEC. However, the MELF pattern was not a predictor of poor prognosis in EEC.

Characterizing the Invasive Tumor Front of Aggressive Uterine Adenocarcinoma and Leiomyosarcoma

The invasive tumor front (the tumor–host interface) is vitally important in malignant cell progression and metastasis. Tumor cell interactions with resident and infiltrating host cells and with the surrounding extracellular matrix and secreted factors ultimately determine the fate of the tumor. Herein we focus on the invasive tumor front, making an in-depth characterization of reticular fiber scaffolding, infiltrating immune cells, gene expression, and epigenetic profiles of classified aggressive primary uterine adenocarcinomas (24 patients) and leiomyosarcomas (11 patients). Sections of formalin-fixed samples before and after microdissection were scanned and studied. Reticular fiber architecture and immune cell infiltration were analyzed by automatized algorithms in colocalized regions of interest. Despite morphometric resemblance between reticular fibers and high presence of macrophages, we found some variance in other immune cell populations and distinctive gene expression and cell adhesion-related methylation signatures. Although no evident overall differences in immune response were detected at the gene expression and methylation level, impaired antimicrobial humoral response might be involved in uterine leiomyosarcoma spread. Similarities found at the invasive tumor front of uterine adenocarcinomas and leiomyosarcomas could facilitate the use of common biomarkers and therapies. Furthermore, molecular and architectural characterization of the invasive front of uterine malignancies may provide additional prognostic information beyond established prognostic factors.

Grossly unremarkable cervix in endometrial carcinomas: lymphovascular space invasion and microcystic elongated and fragmented pattern may be associated with high incidence of cervical stromal involvement

Accurate staging of endometrial carcinoma is crucial to optimize patients' care. A pivotal parameter that pathologists evaluate to guide staging is the presence of cervical stromal involvement. However, the standard protocol for adequate sampling of the cervix is lacking. A total of 71 grossly unremarkable cervices in hysterectomy specimens with endometrial carcinomas have been studied. Sixty-three (89.7%), five (7.0%), and three (4.2%) were FIGO stage I, II, and III, respectively. Of 71 (8.5%) cases, 6 cases had cervical stromal involvement, among which, 4 (67%) showed endometrioid carcinoma (EC), 1 case of serous carcinoma, and 1 carcinosarcoma. Microcystic elongated and fragmented (MELF) pattern was identified in 12 (16.9%) cases, among which 11 were EC. The presence of MELF pattern was associated with advanced age, deeper myometrial invasion, and advanced FIGO stage. Tumors with lower uterine segment involvement (5/6; 80%), lymphovascular space invasion (4/6; 67%), and MELF pattern (3/6; 50.0%) tended to have cervical stromal involvement. Thus, we provide evidence that the presence of these features in hysterectomy specimens from patients with endometrial carcinoma may warrant extended sampling of the cervix while submitting four representative sections (one section from each quadrant) seems adequate to evaluate for occult cervical stromal involvement in grossly unremarkable cervices in the absence of these features.

Assessment of lymphovascular invasion in early stage endometrial carcinoma -a retrospective study

Introduction

Endometrial carcinoma is associated with several known prognostic factors. Recently, lymphovascular invasion (LVI) has gained a prominent position in the risk assessment of early endometrioid endometrial carcinoma, in identifying patients who can benefit from adjuvant radiation therapy. This study aims to assess LVI in early-stage endometrioid endometrial carcinoma accurately with emphasis on its extent /grading. We also propose a few local recommendations for improving LVI reproducibility in endometrial carcinoma to guide future studies.

Methods

The duration of this retrospective study was 2 years. Early-stage I (Ia and Ib), and grade 1 and 2 endometrioid endometrial carcinomas were included. 03 reviewers independently recorded their findings on H&E stained slides. LVI was graded as none, focal and substantial. In discordant cases, immunohistochemical stain CD 31 was used.

All the data was entered in the statistical software SPSS version 26 and analyzed for frequencies. The relationships between various histological parameters assessed and the degree of reproducibility for LVI amongst various observers were also determined.

Results

Out of a total of 70 cases of endometrioid carcinoma diagnosed on hysterectomy specimen, only 32 met our inclusion criteria. The rate of LVI positivity was 6.3 %, 34.4 %, and 37.5 % respectively for reviewers 1, 2, and 3. The degree of reproducibility in LVI assessment and LVI grading was significant amongst reviewers 2 and 3. Also, a significant association was drawn between tumor grade and LVI.

Conclusion

Despite limitations in our study we recommend including both LVI assessment and grading in routine reporting formats locally. By adding a second reviewer in LVI assessment and using CD31 in discrepant cases LVI positivity can be significantly increased.

ARID1A and CTNNB1/β-Catenin Molecular Status Affects the Clinicopathologic Features and Prognosis of Endometrial Carcinoma: Implications for an Improved Surrogate Molecular Classification

The collaborative Cancer Genome Atlas (TCGA) project identified four distinct prognostic groups of endometrial carcinoma (EC) based on molecular alterations: (i) the ultramutated subtype that encompasses POLE mutated (POLE) cases; (ii) the hypermutated subtype, characterized by MisMatch Repair deficiency (MMRd); (iii) the copy-number high subtype, with p53 abnormal/mutated features (p53abn); (iv) the copy-number low subtype, known as No Specific Molecular Profile (NSMP). Although the prognostic value of TCGA molecular classification, NSMP carcinomas present a wide variability in molecular alterations and biological aggressiveness. This study aims to investigate the impact of ARID1A and CTNNB1/β-catenin alterations by targeted Next-generation sequencing (NGS) and immunohistochemistry (IHC) in a consecutive series of 125 molecularly classified ECs. NGS and IHC were used to assign surrogate TCGA groups and to identify molecular alterations of multiple target genes including POLE, PTEN, ARID1A, CTNNB1, TP53. Associations with clinicopathologic parameters, molecular subtypes, and outcomes identified NSMP category as the most heterogeneous group in terms of clinicopathologic features and outcome. Integration of surrogate TCGA molecular classification with ARID1A and β-catenin analysis showed NSMP cases with ARID1A mutation characterized by the worst outcome with early recurrence, while NSMP tumors with ARID1A wild-type and β-catenin alteration had indolent clinicopathologic features and no recurrence. This study indicates how the identification of ARID1A and β-catenin alterations in EC represents a simple and effective way to characterize NSMP tumor aggressiveness and metastatic potential.

Conservative management of grade 2 stage IA endometrial carcinoma and literature review

PURPOSE

To explore the clinical outcomes of megestrol acetate alone or plus metformin in young women with grade 2 stage IA endometrial carcinoma who ask for preserved fertility.

METHODS

Patients with stage IA grade 2 endometrial carcinoma who asked for fertility-sparing treatment in the Obstetrics and Gynecology Hospital of Fudan University between 2015 and 2017 were enrolled and retrospectively reviewed.

RESULTS

Four patients were included and treated with oral megestrol acetate (160 mg per day), while metformin (500 mg, thrice daily) was added for patients with metabolic syndrome. Regular hysteroscopic examination was performed every 3 months during the conservative treatment. Overall, 75% (3/4) of the patients had a complete response, one relapsed and achieved a complete response after changing the therapy plan, and one patient had an indication of myometrial invasion during fertility-sparing treatment and chose to remove uterus.

CONCLUSIONS

Fertility-sparing treatment for stage IA grade 2 endometrial carcinoma patients is worth exploration. Megestrol acetate with or without metformin combined with hysteroscopic lesion ablation may be an effective therapy.

Usual-Type Endocervical Adenocarcinoma with a Microcystic, Elongated, and Fragmented Pattern of Stromal Invasion: A Case Report with Emphasis on Ki-67 Immunostaining and Targeted Sequencing Results

The microcystic, elongated, and fragmented (MELF) pattern is a unique myometrial invasion pattern occasionally found at the invasive front of endometrial endometrioid carcinoma (EEC). Herein, we report an uncommon case of usual-type endocervical adenocarcinoma (UEA) with a MELF pattern. We comprehensively analyzed its clinicopathological and molecular features, which has not been previously documented. A 67-year-old woman presented with a cervical mass and underwent radical hysterectomy. Histologically, the MELF pattern of UEA was almost identical to that of EEC. Tumor glands exhibited a microcystic appearance or elongated structures with compression forming a slit-like lumen. The tumor glands were irregularly fragmented into small clusters or single cells. Cells lining the tumor glands possessed conspicuous eosinophilic cytoplasm with squamoid or flattened endothelium-like appearance. These glands or cells were accompanied by a prominent fibromyxoid stromal reaction. Lymphovascular invasion was occasionally observed. Immunostaining revealed diffuse and strong cytokeratin 7 expression and block p16 positivity in both conventional and MELF components. However, the MELF component displayed a very low Ki-67 proliferation index compared to that of the conventional component, which showed markedly increased Ki-67 expression. Targeted sequencing analysis revealed that the MELF component harbored pathogenic mutations in ARID1A, KRAS, and PTEN, identical to those detected in the conventional component. In summary, the morphological features of the MELF pattern in UEA were similar to those in EEC. We found significant differences in Ki-67 expression status between conventional and MELF components, but the mutational profiles were identical. Our findings should be confirmed in larger cohorts of patients with UEA showing a MELF pattern.

The uterine pathological features associated with sentinel lymph node metastasis in endometrial carcinomas

Background

In recent years, sentinel lymph node excision and ultrastaging have been performed in endometrial carcinomas to obtain information about lymph node status, avoiding unnecessary complete pelvic and paraaortic lymphadenectomy. The purpose of this retrospective study was to provide a comprehensive evaluation of the pathological features of endometrial carcinomas and their significance in association with sentinel lymph node involvement.

Methods

Patients with endometrial carcinomas, preceded by sentinel lymph node mapping, were classified into Group-I and Group-II with negative and positive involvement, respectively. The pathological features, associated with sentinel lymph node involvement, were statistically analyzed, including determination of test performance parameters.

Results

Among 70 patients who had undergone hysterectomy and sentinel lymph node excision, 61 had carcinoma and 9 had atypical hyperplasia. There were 50 patients in Group-I and 10 in Group-II. In Group-II, the significant pathological features were: 1) lower uterine segment involvement (100%), 2) an average tumor size of ≥5 CM, 3) lymphovascular invasion (50%), 4) cervical stromal invasion (40%), and 5) depth of myometrial invasion of ≥50% (50%). The incidences of these pathological features were significantly less in Group-I. Statistical analyses singled out “lower uterine segment involvement” as the most important feature.

Conclusions

We have identified five pathological features which are associated with sentinel lymph node involvement. Since lower uterine segment involvement has occurred in all cases of the Group-II cohort, we recommend FIGO and other organizations that determine staging rules should consider whether tumors that involve the lower uterine segment should be staged as higher than “1a”, if the findings in this small series are confirmed by other studies. The results of this study may guide pathologists and oncologists in the diagnostic and therapeutic approaches to management of endometrial carcinomas.

Pathological features, immunoprofile and mismatch repair protein expression status in uterine endometrioid carcinoma: focus on MELF pattern of myoinvasion

AIMS

Microcystic, elongated, and fragmented (MELF) pattern of myoinvasion has been related with increased risk of lympho-vascular space invasion (LVSI) and lymph node metastasis. We analysed a cohort of endometrioid endometrial carcinomas (EECs) to examine the relationships between the MELF pattern of invasion and the clinico-pathological and immunohistochemical features of EEC.

METHODS AND RESULTS

129 EECs were evaluated for the presence of MELF pattern and immunohistochemically tested for Mismatch repair (MMR) proteins, p16, p53 and beta-catenin. We observed 28 MELF + EECs and 101 MELF- EECs. LVSI was observed in 20 MELF + cases and in MELF- tumors. Lymph-node metastases were observed in 7 MELF + cases (2 macrometastases, 3 micrometastases and 2 ITCs). None of the MELF- cases showed micrometastases or ITCs, 18 cases had macrometastatic lymph-nodes. Statistical analysis showed that MELF + tumors carry an increased risk of developing nodal metastasis independent of tumor dimension and LVSI. Loss of MMR proteins expression was observed in 11 MELF + cases and 45 MELF- cases, respectively. Our data showed a higher frequency of immunohistochemical MLH1-PMS2 loss in MELF- pattern of invasion (32.67% of MELF- cases vs 21.43% of MELF + cases) but a higher prevalence of MSH2-MSH6 loss in MELF + pattern (7.14% in MELF + population vs 3.96% of MELF- population) CONCLUSIONS: The morphological recognition of MELF pattern is more reliable than immunohistochemical and molecular signatures of EEC in predicting the risk of nodal involvement. The observed higher prevalence of MSH2-MSH6 loss in MELF + group and MLH1-PMS2 loss in MELF- group may suggest a different molecular signature.

The clinicopathological characteristics and survival outcomes of endometrial carcinoma coexisting with or arising in adenomyosis: A pilot study

Little is known about the epidemiological and clinicopathological characteristics of endometrial endometrioid carcinoma (EEC) coexisting with or arising in adenomyosis (EEC-A or EEC-AIA) due to their rarity. This study compared EEC-A and EEC-AIA with endometrial carcinoma without adenomyosis. Cases of endometrial cancer treated at the study center from June 1, 2010, to June 1, 2017, were reviewed. The epidemiological, clinicopathological characteristics and survival outcomes were compared among three groups of endometrioid subtypes: group A, stage IA endometrial carcinoma patients without coexisting adenomyosis; group B, patients with EEC-A; and group C, patients with EEC-AIA. Among the 2080 patients reviewed, groups A, B, and C included 1043, 230 and 28 patients, respectively. Patients in group A and group B had similar clinicopathological and survival outcomes. Patients in group C were significantly younger and had less gravidity and parity than patients in groups A and B. More tumors from group C were grade 1, and they had a smaller maximum diameter and less mismatch repair deficiency than those from groups A and B. After a median follow-up of 57.0 months, the 5-year disease-free survival (DFS) rates of groups A, B and C were 96%, 91% and 100% (p = 0.045), respectively; the 5-year overall survival (OS) rates were 98%, 93% and 100%, respectively (p = 0.001), in the Kaplan-Meier analysis. However, these difference disappeared in a subgroup of stage IA patients in univariate and multivariate analysis. Cox regression analysis in stage IA patients also revealed no significant differences in survival outcome across the three groups. In conclusion, EEC-AIA exhibited specific clinicopathological characteristics that were probably associated with favorable survival outcomes. The characteristics and survival outcomes of EEC-A were similar to those of EEC without adenomyosis in stage IA patients.

The role of adjuvant radiotherapy in stage I endometrial cancer: A single-institution outcome

OBJECTIVE

Postoperative radiotherapy for early endometrial cancer has been investigated in several randomized trials. These trials demonstrate that it reduces loco-regional recurrence, but has no impact on overall survival. The aims of this study were to better understand the role of adjuvant radiotherapy and determine predictors for loco-regional recurrence or development of distant metastasis.

MATERIALS AND METHODS

A retrospective medical records review was performed on patients with surgical stage I endometrial cancer treated at Taipei Veterans General Hospital between 2006 and 2013. Multivariable analysis was conducted using Cox regression for prognostic predictors.

RESULTS

A total of 337 patients were identified. The estimated five-year overall survival and loco-regional recurrence-free survival were 96.3% and 97.9% in the non-radiotherapy group, and 91.6% and 97.1% in the radiotherapy group (p = 0.06 overall survival, p = 0.956 loco-regional recurrence-free survival). Multivariable analysis revealed that elevated preoperative serum Cancer Antigen 125 (CA-125) level (hazard ratio (HR) = 2.54), age older than 60 years old (HR = 3.34), and depth of myometrial invasion > 50% (HR = 3.37) were significant factors in overall survival. Elevated preoperative CA-125 level (HR = 5.37), age older than 60 years (HR = 6.57), positive lymphovascular space invasion (HR = 50.20), and adjuvant radiotherapy (HR = 0.05) were independent predictors of loco-regional recurrence-free survival. For distant metastasis, deep myometrial invasion was a significant risk factor.

CONCLUSIONS

Postoperative radiotherapy delivery is an independent predictor for loco-regional recurrence-free survival but has no impact on overall survival in this population. Preoperative CA-125 level is a risk factor for loco-regional recurrence, and deep myometrial invasion was correlated with distant metastasis.

Myoinvasive Pattern as a Prognostic Marker in Low-Grade, Early-Stage Endometrioid Endometrial Carcinoma

Low-grade and early Federation for Gynecology and Obstetrics (FIGO) stage endometrioid endometrial carcinomas (EEC) have an excellent prognosis. However, approximately 10% of patients develop recurrence, which cannot be correctly predicted at diagnosis. We evaluated myoinvasive patterns as a prognostic factor of relapse in low-grade, early-stage EEC. Two-hundred and fifty-eight cases were selected according to the following inclusion criteria: (i) endometrioid endometrial carcinomas, (ii) grade 1 or 2 with (iii) FIGO stage I or II, and (iv) clinical follow-up. Slides were reviewed to annotate the myoinvasive pattern present in each case (infiltrative glands, microcystic, elongated and fragmented -MELF-, broad front, adenomyosis-like and adenoma malignum). Microsatellite instability was studied by immunoexpression of mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6). There were 29 recurrences (11.2%) among the 258 cases analysed. A predominant broad front myoinvasive pattern was significantly associated with tumour relapse (p = 0.003). The presence of a pattern of infiltrative glands (p = 0.001) and microsatellite instability (p = 0.004) were associated with lower disease-free survival, without having an impact on overall survival. Our observations suggest the potential value of the pattern of myoinvasion as a prognostic factor in low-grade, early-stage endometrioid endometrial carcinoma.

A Deceptive Spread: Myoinvasion of Endometrial Carcinoma Imitating Adenoma Malignum

Endometrioid type of endometrial carcinoma is the most common form of uterine malignancy. The majority of patients in the developed world present with the low-grade, low-stage type of this malignancy. The current treatment of early-stage endometrioid carcinoma provides most patients with a favorable outcome. One of the important factors that determine the outcome of early-stage endometrial carcinoma is the involvement of cervical stroma. One of the very rare forms of cervical stromal involvement by endometrioid carcinoma is termed "adenoma malignum type" invasion due to its similarity to the infamously deceptive type of cervical adenocarcinoma called adenoma malignum. Since adenoma malignum is often discovered incidentally, finding adenoma malignum type of myoinvasion may deceive a pathologist to diagnose the simultaneous presence of endometrial carcinoma and adenoma malignum in the same patient as 2 separate entities. Also, this type of myoinvasion may be missed altogether for its subtle nature. In this article, we report a case of low-grade, low-stage endometrioid carcinoma with adenoma malignum type of myoinvasion. We have pointed out the subtle nature of this lesion and the important features to remember to successfully identify it.

Early-stage endometrial cancer, CTNNB1 mutations, and the relation between lymphovascular space invasion and recurrence

INTRODUCTION

Women diagnosed with early-stage (FIGO 1) endometrial cancer, grade 1 and 2 can have a good prognosis. Most of these women can be treated successfully with a hysterectomy and bilateral salpingo-oophorectomy and without the additional adjuvant treatment that is accompanied by more risks for complications. However, when recurrence does occur, the consequences can be dire. Accurate decisions must therefore be made by surgeons to avoid either under- or over-treatment. Risk and patient stratification for tailoring treatment still need further improvement. Both histopathology and genetic variants could be integrated into the decision process if relevant factors were identified.

MATERIAL AND METHODS

Morphological features and the presence of selected genetic mutations in isolated malignant endometrial epithelial cells from these tumors were analyzed in a strictly defined cohort of FIGO 1, grade 1 and 2 low-risk endometrial cancer. Their presence in this cohort, their relation to recurrence, and the association between histopathological features and mutations were determined. This analysis was performed using archival formalin-fixed paraffin-embedded tissue, complete re-evaluation of histopathological features, laser capture microdissection of epithelial cells, and a polymerase chain reaction-based mutational screening assay.

RESULTS

Twenty-one women with recurrence, after initial identification as low-risk endometrial cancer, were compared with 20 matched control women. The histological marker of lymphovascular invasion was significantly associated with recurrence. There was also a very high prevalence of mutations in CTNNB1 gene, occurring in 50% of this cohort. PTEN mutations were also observed in 27.8% of cases and PIK3CA mutations in 22.2%; none of these mutations were significantly related to recurrence.

CONCLUSIONS

This study supports the importance of lymphovascular space invasion to identify women with significant risk for recurrence in initially low-risk, early-stage endometrial cancer. It also identifies CTNNB1 as a significant mutation in early-stage disease, and although it may not represent a marker for recurrence its high prevalence in early stage disease could have relevance for both pathogenesis and early treatment.

[S3 guidelines on the diagnosis and treatment of carcinoma of the endometrium : Requirements for pathology]

The present article summarises the relevant aspects of the S3 guidelines on endometrioid carcinomas. The recommendations include the processing rules of fractional currettings as well as for hysterectomy specimens and lymph node resections (including sentinel lymph nodes). Besides practical aspects, the guidelines consider the needs of the clinicians for appropriate surgical and radiotherapeutic treatment of the patients. Carcinosarcomas are assigned to the endometrial carcinoma as a special variant. For the first time, an algorithmic approach for evaluation of the tumour tissue for Lynch syndrome is given. Prognostic factors based on morphologic findings are summarised.

ARID1A and PI3-kinase pathway mutations in the endometrium drive epithelial transdifferentiation and collective invasion

ARID1A and PI3-Kinase (PI3K) pathway alterations are common in neoplasms originating from the uterine endometrium. Here we show that monoallelic loss of ARID1A in the mouse endometrial epithelium is sufficient for vaginal bleeding when combined with PI3K activation. Sorted mutant epithelial cells display gene expression and promoter chromatin signatures associated with epithelial-to-mesenchymal transition (EMT). We further show that ARID1A is bound to promoters with open chromatin, but ARID1A loss leads to increased promoter chromatin accessibility and the expression of EMT genes. PI3K activation partially rescues the mesenchymal phenotypes driven by ARID1A loss through antagonism of ARID1A target gene expression, resulting in partial EMT and invasion. We propose that ARID1A normally maintains endometrial epithelial cell identity by repressing mesenchymal cell fates, and that coexistent ARID1A and PI3K mutations promote epithelial transdifferentiation and collective invasion. Broadly, our findings support a role for collective epithelial invasion in the spread of abnormal endometrial tissue.

PIK3CA mutations and ARID1A loss co-exist in endometrial neoplasms. Here, the authors show that these co-mutations drive gene expression profiles correlated with differential chromatin accessibility and ARID1A binding in the endometrial epithelium, resulting in partial EMT and myometrial invasion.

Endometrial Carcinoma, Grossing and Processing Issues: Recommendations of the International Society of Gynecologic Pathologists

Endometrial cancer is the most common gynecologic neoplasm in developed countries; however, updated universal guidelines are currently not available to handle specimens obtained during the surgical treatment of patients affected by this disease. This article presents recommendations on how to gross and submit sections for microscopic examination of hysterectomy specimens and other tissues removed during the surgical management of endometrial cancer such as salpingo-oophorectomy, omentectomy, and lymph node dissection—including sentinel lymph nodes. In addition, the intraoperative assessment of some of these specimens is addressed. These recommendations are based on a review of the literature, grossing manuals from various institutions, and a collaborative effort by a subgroup of the Endometrial Cancer Task Force of the International Society of Gynecological Pathologists. The aim of these recommendations is to standardize the processing of endometrial cancer specimens which is vital for adequate pathological reporting and will ultimately improve our understanding of this disease.

Preoperative Prediction of Lymph Nodal Metastases in Endometrial Carcinoma: Is it Possible?: A Literature Review

BACKGROUND

Lymph node status is one of the most important prognostic factors in endometrial cancer and crucial for deciding adjuvant therapy.

OBJECTIVE

The aim of the study was to assess the different models used to predict lymphatic nodal disease.

SEARCH STRATEGY

A literature search was conducted to detect the relevant studies.

INCLUSION CRITERIA

Relevant papers comparing the preoperative modality with the final histopathological results including randomized clinical trials, case-control studies, and any publications with a minimum of 50 patients in the report.

RESULTS

Molecular-based predictors are still far from a practical application. Preoperative radiological scans (positron emission tomography, computed tomography, magnetic resonance imaging, and ultrasound) have shown the best predictor of lymphatic dissemination. However, there is currently no ideal model available, which can be used within standard clinical care.

CONCLUSIONS

Surgical staging still remains the criterion standard in the determination of lymph node status in endometrial cancer.

Clinical and ultrasound characteristics of the microcystic elongated and fragmented (MELF) pattern in endometrial cancer according to the International Endometrial Tumor Analysis (IETA) criteria

Objectives

To describe sonographic features of the microcystic elongated and fragmented (MELF) pattern of myometrial invasion (MI) using the International Endometrial Tumor Analysis (IETA) criteria; to assess the effect of the MELF pattern on preoperative ultrasound evaluation of MI; and to determine the relationship of the MELF pattern to more advanced stage (≥ IB) and lymph node metastases in women with endometrioid endometrial cancer.

Methods/materials

We included 850 women with endometrioid endometrial cancer from the prospective IETA 4 study. Ultrasound experts performed all ultrasound examinations, according to the IETA protocol. Reference pathologists assessed the presence or absence of the MELF pattern. Sonographic features and accuracy of ultrasound assessment of MI were compared in cases with the presence and the absence of the MELF pattern. The MELF pattern was correlated to more advanced stage (≥IB) and lymph node metastases.

Results

The MELF pattern was present in 197 (23.2%) women. On preoperative ultrasound imaging the endometrium was thicker (p = 0.031), more richly vascularized (p = 0.003) with the multiple multifocal vessel pattern (p < 0.001) and the assessment of adenomyosis was more often uncertain (p < 0.001). The presence or the absence of the MELF pattern did not affect the accuracy of the assessment of MI. The MELF pattern was associated with deep myometrial invasion ≥ 50% (p < 0.001), cervical stromal invasion (p = 0.037), more advanced stage (≥ IB) (p < 0.001) and lymph node metastases (p = 0.011).

Conclusions

Tumors with the MELF pattern were slightly larger, more richly vascularized with multiple multifocal vessels and assessment of adenomyosis was more uncertain on ultrasound imaging. The MELF pattern did not increase the risk of underestimating MI in preoperative ultrasound staging. Tumors with the MELF pattern were more than twice as likely to have more advanced stage (≥ IB) and lymph node metastases.

A Selected Immunohistochemical Panel Aids in Differential Diagnosis and Prognostic Stratification of Subtypes of High-grade Endometrial Carcinoma: A Clinicopathologic and Immunohistochemical Study at a Single Institution

This study aimed to investigate whether a selected immunohistochemical panel (estrogen receptor, p53, ARID1A, PPP2R1A, HNF-1β) could contribute to the diagnostic process of high-grade endometrial carcinomas (HG-ECs). We also aimed to analyze the correlation of these immunohistochemical results with several morphologic variables and survival data. After revising the diagnosis of 78 HG-ECs, immunohistochemical analysis was performed for each case. After immunohistochemical analysis, a specific diagnosis of prototypic HG-EC was established in most of the cases that were uncertain due to morphologic ambiguity. In the univariate analysis, older patient age, type II morphology, undifferentiated carcinoma and carcinosarcoma type of histology, altered p53 immunostaining, strong membranous staining of PPP2R1A, presence of lymphovascular invasion in serous carcinoma, and microcystic, elongated, and fragmented-type infiltration pattern in endometrioid carcinoma were significantly related to poor prognosis. In the multivariate analysis, only older patient age and carcinosarcoma or undifferentiated/dedifferentiated carcinoma type histology were found to be significantly poor prognostic factors (P=0.011), whereas advanced FIGO stage and type II histology were found to be correlated with poor prognosis, but did not reach statistical significance. We suggest that immunohistochemistry should be used in the differential diagnosis of HG-ECs, especially those with ambiguous morphology. Markers used in this study made a valuable contribution to the diagnostic process as well as prediction of prognosis.

Active K-RAS induces the coherent rotation of epithelial cells: A model for collective cell invasion in vitro

At the invasive front of adenocarcinomas, single cells and multicellular structures exist; the latter include glands and cell clusters, such as tumor buddings and poorly differentiated clusters. Recent reports suggest the importance of collective cell migration in metastasis; however, it is technically difficult to observe the movement of multicellular structures in vivo. We utilized MDCK cells as a model for epithelial cells and established a method to quantify their motility in 3D structures in vitro. A single MDCK cell grows as a cell cluster in the gel and later proliferates and forms a cyst. Active K-RAS expression induced rotation of both the cell clusters and the cysts. The rotation speed of cell clusters was 4 times higher than that of cysts. The screening of inhibitors for their effects on cell clusters and cysts revealed that cyclin B1 and β-catenin were the key molecules for their rotation, respectively. Regulators for cyst rotation, such as vorinostat and β-catenin, were not effective for inducing cell cluster rotation. These results indicate that the signaling pathways of cell dynamics are different between cell clusters and cysts. As cell clusters are related to lymph node involvement and the prognosis of various carcinomas, our in vitro quantitative system may be useful for the screening of drugs to prevent lymphatic invasion.

MELF pattern of myometrial invasion and role in possible endometrial cancer diagnostic pathway: A systematic review of the literature

Microcystic, elongated, fragmented (MELF) pattern of myometrial invasion has been proposed as a prognostic marker in patients with endometrial carcinoma (EC). Its prognostic and predictive effect still remains elusive. The aim of the present study is to accumulate the current knowledge on the role of MELF pattern in the prognosis and survival of patients with EC. Medline, Scopus, Google Scholar, and Clinicaltrials.gov databases were searched for articles published up to May 2018, along with the references of all articles. Prospective and retrospective trials reporting outcomes of cases with EC who were examined for MELF pattern were considered eligible for inclusion in the present systematic review. Of the 196 records screened, 14 were considered eligible. A total of 14 studies which comprised 588 women were finally included in the present systematic review. All the included patients were evaluated for presence of MELF pattern of myometrial invasion. MELF positive (+) patients were more likely to present with larger and higher grade tumors, lymph node metastasis, lymphovascular invasion and >50% myometrial invasion. No difference was reported in disease free survival (DFS) and disease specific survival (DSS) as well as in vaginal recurrence rates. MELF (+) was reported as a significant indicator of survival. In conclusion, MELF pattern of myometrial invasion plays a critical role in lymphovascular space invasion and lymph node metastasis in patients with EC. Regardless, its implication in survival and recurrences is ill determined.

MELF Pattern for Predicting Lymph Node Involvement and Survival in Grade I-II Endometrioid-type Endometrial Cancer

The aim of this study was to examine the associations between microcystic, elongated, and fragmented (MELF) pattern and other prognostic factors and lymph node involvement, disease-free survival, and overall survival (OS) using a case-control group consisting of grade I-II endometrioid endometrial carcinoma (EEC) patients with/without lymph node involvement. The files of the patients were searched electronically for all hysterectomy specimens with a diagnosis of grade I-II EEC of the uterine body from January 1, 2008 to July 31, 2014. Lymph node involvement was detected in 27 patients who were histologically diagnosed with grade I-II EEC, and these patients made up the case group. Using a dependent random sampling method, 28 grade I-II EEC patients without lymph node involvement were selected. According to multivariate regression analysis, lymphovascular space invasion [odds ratio, 23.5; 95% confidence interval (CI), 2.4-223.5] and MELF pattern (odds ratio, 13.3; 95% CI, 1.4-121.8) were significant predictors of lymph node involvement. There was recurrence in 15.8% of cases that showed a MELF pattern and in 19.4% of those that did not (P=0.738). According to Kaplan-Meier analysis, the MELF pattern revealed no significant differences in disease-free survival (hazard ratio, 1.0; 95% CI, 0.1-36.5), whereas the effect on OS was significant (hazard ratio, 2.2; 95% CI, 1.3-4.2). The presence of MELF pattern was a substantial risk factor for detecting lymph node involvement in patients with grade I-II EEC. The MELF pattern may be important for identifying which patients need staging surgery, in addition to its effect on the OS.

Fertility-Sparing Treatment of Endometrial Cancer with Initial Infiltration of Myometrium by Resectoscopic Surgery: A Pilot Study

Three women with a well-differentiated grade 1 endometrioid adenocarcinoma of the endometrium with minimal myometrial infiltration were treated with hysteroscopic resection and hormone therapy. The presence of myometrial infiltration has often been mentioned as an exclusion criterion for conservative management in young patients because of worsening cancer prognosis. The subsequent 5-year follow-up and the pregnancies achieved may confirm the choice of this temporary treatment and indicate a new option for fertility-sparing treatment in highly motivated patients.

Characterization of cytoplasmic cyclin D1 as a marker of invasiveness in cancer

Cyclin D1 (Ccnd1) is a proto-oncogen amplified in many different cancers and nuclear accumulation of Ccnd1 is a characteristic of tumor cells. Ccnd1 activates the transcription of a large set of genes involved in cell cycle progress and proliferation. However, Ccnd1 also targets cytoplasmic proteins involved in the regulation of cell migration and invasion. In this work, we have analyzed by immunohistochemistry the localization of Ccnd1 in endometrial, breast, prostate and colon carcinomas with different types of invasion. The number of cells displaying membranous or cytoplasmic Ccnd1 was significantly higher in peripheral cells than in inner cells in both collective and pushing invasion patterns of endometrial carcinoma, and in collective invasion pattern of colon carcinoma. Also, the cytoplasmic localization of Ccnd1 was higher when tumors infiltrated as single cells, budding or small clusters of cells. To evaluate cytoplasmic function of cyclin D1, we have built a variant (Ccnd1-CAAX) that remains attached to the cell membrane therefore sequestering this cyclin in the cytoplasm. Tumor cells harboring Ccnd1-CAAX showed high levels of invasiveness and metastatic potential compared to those containing the wild type allele of Ccnd1. However, Ccnd1-CAAX expression did not alter proliferative rates of tumor cells. We hypothesize that the role of Ccnd1 in the cytoplasm is mainly associated with the invasive capability of tumor cells. Moreover, we propose that subcellular localization of Ccnd1 is an interesting guideline to measure cancer outcome.

Promoter-level transcriptome in primary lesions of endometrial cancer identified biomarkers associated with lymph node metastasis

For endometrial cancer patients, lymphadenectomy is recommended to exclude rarely metastasized cancer cells. This procedure is performed even in patients with low risk of recurrence despite the risk of complications such as lymphedema. A method to accurately identify cases with no lymph node metastases (LN-) before lymphadenectomy is therefore highly required. We approached this clinical problem by examining primary lesions of endometrial cancers with CAGE (Cap Analysis Gene Expression), which quantifies promoter-level expression across the genome. Fourteen profiles delineated distinct transcriptional networks between LN + and LN- cases, within those classified as having the low or intermediate risk of recurrence. Subsequent quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses of 115 primary tumors showed SEMA3D mRNA and TACC2 isoforms expressed through a novel promoter as promising biomarkers with high accuracy (area under the receiver operating characteristic curve, 0.929) when used in combination. Our high-resolution transcriptome provided evidence of distinct molecular profiles underlying LN + /LN- status in endometrial cancers, raising the possibility of preoperative diagnosis to reduce unnecessary operations in patients with minimum recurrence risk.

Whether intermediate-risk stage 1A, grade 1/2, endometrioid endometrial cancer patients with lesions larger than 2 cm warrant lymph node dissection?

Background

Our research aimed to investigate whether lymphadenectomy was required in patients with intermediate-risk endometrioid endometrial cancer (EEC).

Methods

Between 1989 and 2015, 1009 patients with intermediate-risk EEC: grade 1 or 2 tumor, <50% myometrial invasion, and a tumor diameter ≥ 2 cm and 818 low-risk patients with grade 1 or 2 tumor, <50% myometrial invasion, and a tumor diameter < 2 cm were enrolled in this study. The rate and risk factors of node metastasis were evaluated and compared between the two risk groups. Survival data were analyzed in patients with intermediate-risk EEC with or without lymphadenectomy.

Results

In all, 624 of 1009 (61.8%) patients with intermediate-risk EEC underwent pelvic ± para-aortic lymphadenectomy with a nodal metastasis rate of 1.9% (12/624), whereas 394 of 818 (48.2%) patients with low-risk EEC underwent pelvic ± para-aortic lymphadenectomy with a nodal metastasis rate of 0.3% (1/394) (p = 0.021). Notably, intermediate-risk EEC patients with a microcystic, elongated and fragmented (MELF) pattern of invasion, lymphatic vascular space invasion (LVSI), diffuse lesions, or lesions located in the cornua were more likely to have node metastasis. The 5-year overall cancer-related survival and the recurrence-free survival rates of the 742 intermediate-risk EEC patients who were followed for more than 3 years were 99.4% and 94.7%, respectively. In intermediate-risk group, 6 patients (6/443, 1.4%) with lymphadenectomy and 9 patients (9/299, 3.0%) without lymphadenectomy recurred, with a mean recurrence time of 38.3 and 18.7 months respectively. The five-year overall and recurrence-free survival rates of intermediate-risk patients with and without lymphadenectomy were similar (100% vs 98.9%, p = 0.351; 95.2% vs 93.3%, p = 0.464).

Conclusion

Patients with intermediate-risk EEC have low nodal metastasis rate and a favorable outcome whether lymphadenectomy is performed or not. Omission of lymphadenectomy may be a reasonable option in the surgical management of patients with intermediate-risk EEC.

Association between Morphological Patterns of Myometrial Invasion and Cancer Stem Cell Markers in Endometrial Endometrioid Carcinoma

In endometrial endometrioid adenocarcinoma (EEC), the depth of myometrial invasion (MI) is an important parameter for determining whether additional treatment is warranted. The present study investigated the association between MI patterns, cancer stem cell (CSC) phenotypes, and their clinicopathological significance in EEC. A total of 73 cases of EEC with MI were examined in this study. Haematoxylin and eosin-stained tissue specimens were analysed for MI pattern, which was categorised as infiltrating; expansile; adenomyosis (AM)-like; or microcystic, elongated, and fragmented (MELF)-type. The expression of CSC markers such as cluster of differentiation (CD)44, CD133, and Nanog1, as well as oestrogen receptor (ER) and progesterone receptor (PR) was examined by immunohistochemistry. Clinicopathological features including age, DOI, MI pattern, LVI, lymph node (LN) metastasis, disease progression, and survival outcome were recorded. Most examined cases (45/73) were International Federation of Gynecology and Obstetrics (FIGO) stage I. MI showed infiltrating (49.3%), AM-like (26.3%), MELF (15.1%), and expansile (9.6%) patterns. Tumours with the infiltrating pattern were associated with high FIGO grade (P = 0.002), reduced ER and PR, and CD44 expression (P = 0.014, 0.026, and 0.030, respectively); those with a MELF pattern showed LN metastasis (P < 0.001), lymphovascular invasion (P = 0.011), and reduced ER, CD44, and CD133 expression (P = 0.036, 0.006, and 0.016, respectively). EEC with infiltrating/MELF patterns of MI is associated with worse prognosis. These results suggest that CSC expression profiles are an unfavourable indicator of EEC.

Microcystic, elongated, and fragmented pattern of invasion in relation to histopathologic and clinical prognostic factors in endometrioid endometrial adenocarcinoma

Objective:

To investigate the association of microcystic, elongated, and fragmented (MELF) pattern of invasion with prognostic factors in endometrioid endometrial adenocarcinoma (EEA).

Material and Methods:

Stained tissue sections from 83 cases of EEA operated by the same gynecologic oncologist were reviewed to identify cases showing MELF-type invasion in this retrospective study. The association of MELF pattern with age, tumor grade, depth of myometrial invasion, and presence of lymphovascular space invasion (LVSI) was analyzed.

Results:

FIGO grade 2 and grade 1 tumors were evident in 53.0% and 38.6% of patients, respectively. Depth of myometrial invasion was <50% in 72.0% of patients, and LVSI was absent in 77.1%. MELF pattern was confirmed in 35 (42.2%) patients. Presence of MELF pattern was associated with significantly higher mean ± standard deviation age (62.9±6.9) years vs. 58.9±9.1 years, p=0.033), and found to be more likely in patients with high-grade tumor (FIGO grade III; 85.7% vs. 14.3%, p<0.001), deep (≥50%) myometrial invasion (78.3% vs. 21.7%, p<0.001), and presence of LVSI (94.7% vs. 5.3%, p<0.001) as compared with absence of MELF pattern.

Conclusion:

In conclusion, our findings revealed a high rate of MELF pattern among patients with EEA alongside the association of MELF pattern with poor prognostic factors such as high grade tumor, deep myometrial invasion, and LVSI.