Nonendometrioid endometrial carcinomas

High-grade endometrial carcinomas: Morphologic spectrum and molecular classification

High-grade endometrial carcinoma (HGEC) is a heterogeneous group of tumors with various morphologic, genetic, and clinical characteristics. Morphologically, HGEC includes high-grade endometrioid carcinoma, serous carcinoma, clear cell carcinoma, undifferentiated/dedifferentiated carcinoma, and carcinosarcoma. The morphologic classification has been used for prognostication and treatment decisions. However, patient management based on morphologic classification is limited by suboptimal interobserver reproducibility, variable clinical outcomes observed within the same histotype, and frequent discordant histotyping/grading between biopsy and hysterectomy specimens. Recent studies from The Cancer Genome Atlas (TCGA) Research Network established four distinct molecular subtypes: POLE-ultramutated, microsatellite unstable, copy number high, and copy number low groups. Compared to histotyping, the TCGA molecular classification appears superior in risk stratification. The best prognosis is seen in the POLE-ultramutated group and the worst in copy number high group, while the prognosis in the microsatellite unstable and copy number low groups is in between. The TCGA subtyping is more reproducible and shows a better concordance between endometrial biopsy and resection specimens. It has now become apparent that the molecular classification can supplement histotyping in patient management. This article provides an overview of the pathologic diagnosis/differential diagnosis of HGEC and the TCGA classification of endometrial cancers, with the clinical significance and applications of TCGA classification briefly discussed when appropriate.

Associations between Genetically Predicted Circulating Protein Concentrations and Endometrial Cancer Risk

Simple Summary

Endometrial cancer is the leading female reproductive tract cancer in developed countries. Discovering new biomarkers is critical for understanding the etiology this cancer and identifying women with a higher risk of this cancer from the general population. Several blood protein biomarkers have been linked to endometrial cancer in previous studies, but these studies have assessed only a limited number of biomarkers usually among a small number of participants. The current study aimed at identifying novel circulating protein biomarkers of endometrial cancer by using the largest available dataset to date. Our finding suggested nine proteins to be associated with endometrial cancer risk, and five of the identified associations showed suggestive associations with risk of non-endometrioid EC, a much more lethal subtype. If validated by additional studies, our findings may contribute to understanding the pathogenesis of endometrial tumor development and facilitating the risk assessment of endometrial cancer.

Abstract

Endometrial cancer (EC) is the leading female reproductive tract malignancy in developed countries. Currently, genome-wide association studies (GWAS) have identified 17 risk loci for EC. To identify novel EC-associated proteins, we used previously reported protein quantitative trait loci for 1434 plasma proteins as instruments to evaluate associations between genetically predicted circulating protein concentrations and EC risk. We studied 12,906 cases and 108,979 controls of European descent included in the Endometrial Cancer Association Consortium, the Epidemiology of Endometrial Cancer Consortium, and the UK Biobank. We observed associations between genetically predicted concentrations of nine proteins and EC risk at a false discovery rate of <0.05 (p-values range from 1.14 × 10⁻¹⁰ to 3.04 × 10⁻⁴). Except for vascular cell adhesion protein 1, all other identified proteins were independent from known EC risk variants identified in EC GWAS. The respective odds ratios (95% confidence intervals) per one standard deviation increase in genetically predicted circulating protein concentrations were 1.21 (1.13, 1.30) for DNA repair protein RAD51 homolog 4, 1.27 (1.14, 1.42) for desmoglein-2, 1.14 (1.07, 1.22) for MHC class I polypeptide-related sequence B, 1.05 (1.02, 1.08) for histo-blood group ABO system transferase, 0.77 (0.68, 0.89) for intestinal-type alkaline phosphatase, 0.82 (0.74, 0.91) for carbohydrate sulfotransferase 15, 1.07 (1.03, 1.11) for D-glucuronyl C5-epimerase, and 1.07 (1.03, 1.10) for CD209 antigen. In conclusion, we identified nine potential EC-associated proteins. If validated by additional studies, our findings may contribute to understanding the pathogenesis of endometrial tumor development and identifying women at high risk of EC along with other EC risk factors and biomarkers.

Prognostic factors and treatment outcomes in surgically-staged non-invasive uterine clear cell carcinoma: a Turkish Gynecologic Oncology Group study

OBJECTIVE

To assess the prognosis of surgically-staged non-invasive uterine clear cell carcinoma (UCCC), and to determine the role of adjuvant therapy.

METHODS

A multicenter, retrospective department database review was performed to identify patients with UCCC who underwent surgical treatment between 1997 and 2016 at 8 Gynecologic Oncology Centers. Demographic, clinicopathological, and survival data were collected.

RESULTS

A total of 232 women with UCCC were identified. Of these, 53 (22.8%) had surgically-staged non-invasive UCCC. Twelve patients (22.6%) were upstaged at surgical assessment, including a 5.6% rate of lymphatic dissemination (3/53). Of those, 1 had stage IIIA, 1 had stage IIIC1, 1 had stage IIIC2, and 9 had stage IVB disease. Of the 9 women with stage IVB disease, 5 had isolated omental involvement indicating omentum as the most common metastatic site. UCCC limited only to the endometrium with no extra-uterine disease was confirmed in 41 women (73.3%) after surgical staging. Of those, 13 women (32%) were observed without adjuvant treatment whereas 28 patients (68%) underwent adjuvant therapy. The 5-year disease-free survival rates for patients with and without adjuvant treatment were 100.0% vs. 74.1%, respectively (p=0.060).

CONCLUSION

Extra-uterine disease may occur in the absence of myometrial invasion (MMI), therefore comprehensive surgical staging including omentectomy should be the standard of care for women with UCCC regardless of the depth of MMI. Larger cohorts are needed in order to clarify the necessity of adjuvant treatment for women with UCCC truly confined to the endometrium.

Alveolar Soft Part Sarcoma of the Female Genital Tract: A Morphologic, Immunohistochemical, and Molecular Cytogenetic Study of 10 Cases With Emphasis on its Distinction From Morphologic Mimics

Alveolar soft part sarcoma (ASPS) is a morphologically distinctive neoplasm of unknown differentiation that bears a characteristic gene fusion involving ASPSCR1 and TFE3. ASPS can occur in the female genital tract, but is rare. Eleven cases with an initial diagnosis of ASPS at female genital tract sites were evaluated for their morphologic features and immunoprofile using a panel of antibodies (TFE3, HMB45, melan-A, smooth muscle actin, desmin, and h-Caldesmon). In addition, the presence of TFE3 rearrangement and subsequent ASPSCR1-TFE3 fusion were determined by fluorescence in situ hybridization. Ten tumors retained their classification as ASPS based on their morphologic appearance, immunohistochemical profile, and demonstration of ASPSCR1-TFE3 fusion. The remaining case was reclassified as conventional-type PEComa due to its pattern of HMB45, melan-A, and desmin positivity as well as absence of TFE3 rearrangement. Sites of the 10 ASPS were uterine corpus (3), cervix (2), uterus not further specified (2), vagina (2), and vulva (1). The age of the patients ranged from 15 to 68 years (mean 34 y, median 32 y). The tumors demonstrated a spectrum of morphologic features, but all had a consistent immunophenotype of strong TFE3 nuclear expression and lack of muscle (smooth muscle actin, desmin, h-Caldesmon) and melanocytic (melan-A, HMB45) markers, except focal positivity for HMB45 in 1. Follow-up was available for 4 patients ranging from 1 to 35 months (mean 15 mo, median 25 mo) and they were alive and had no evidence of recurrence or metastasis at last follow-up. Distinguishing ASPS from its morphologic mimics, particularly PEComa, is important due to increasingly efficacious targeted agents such as MET-selective and VEGF signaling inhibitors in the former and mTOR inhibition therapy in the latter.

Mucinous Adenocarcinoma of the Endometrium Compared With Endometrioid Endometrial Cancer: A SEER Analysis

OBJECTIVE

Mucinous endometrial cancer (MEC) is a rare histologic subtype of endometrial cancers. The purpose of this study is to compare the outcomes of patients with MEC with patients with endometrioid endometrial cancers (EEC), and to determine whether there are significant clinicopathologic differences between these tumors.

METHODS

Surveillance, Epidemiology, and End Results (SEER) Program data for 1988 to 2009 was reviewed. Demographic and clinical data were compared. The impact of histology on survival was analyzed using the Kaplan-Meier method. Factors predictive of outcome were compared using the Cox proportional hazards model.

RESULTS

The study group consisted of 104,659 women, 103,097 (98.5%) had EEC and 1562 (1.5%) MEC. The mean age at diagnosis for EEC and MEC was 62 and 63.4, respectively (P<0.001). MEC tumors were more frequently classified as grade 1 (51.3% vs. 44%; P<0.001). In patients with MEC, a higher rate of pelvic lymph node metastasis (16.3% vs. 10.4%; P<0.001) was noted, but not para-aortic lymph node metastasis (5.1% vs. 4%; P=0.1). After adjusting for race, period of diagnosis, SEER registry, marital status, stage, age, surgery, radiotherapy, grade, histology, and lymph node dissection, there was no difference in survival between MEC and EEC (hazard ratio 0.90; 95% confidence interval, 0.78-1.05).

CONCLUSIONS

Mucinous histology does not significantly affect survival when compared with endometrioid histology in endometrial cancer. Patients with MEC were more likely to have positive pelvic lymph nodes at the time of surgery.

Practical issues in the diagnosis of serous carcinoma of the endometrium

Serous carcinoma (SC) represents ~10% of endometrial carcinomas, but is responsible for almost 40% of cancer deaths. This article reviews the main pathological features, differential diagnosis, and the usefulness of molecular pathology and immunohistochemistry in its diagnosis. Most helpful features for the diagnosis include: irregularly shaped and sized papillae, slit-like spaces, cell stratification and budding, highly atypical cells, architectural and cytological discordance in pseudoglandular tumors, as well as lack of endometrioid features. SC shows typically a predominant papillary growth, which is also found in some subtypes of endometrioid carcinoma of the endometrium (EEC). Distinction is easy when attention is paid to the presence of diffuse marked nuclear pleomorphism, but also to the complex papillary architecture. SC may also show a solid or pseudoglandular patterns, and in these cases differential diagnosis may be difficult with EEC grade 3. Moreover, a high proportion of SC may exhibit clear cells, and, thus, may be confused with clear cell carcinoma. Finally, it is sometimes difficult to distinguish mixed SC-EEC, from SC that combines papillary and pseudoglandular growths. Although there is not a single immunohistochemical marker for distinguishing SC from its mimickers, some antibodies are useful (p53, p16, IMP2, and IMP3), particularly when used in combination. Diagnosis of SC may be even more problematic in small biopsies; a diagnosis of high-grade endometrial carcinoma, SC component can not be excluded, is acceptable as a managerial approach, so it could be taken into account at the time of final surgery.

Verrucous carcinoma of the endometrium: a rare and challenging diagnosis

Verrucous carcinoma of the endometrium is an exceedingly rare disease with only a few cases reported in the literature. We describe the case of a 68-year-old postmenopausal patient who presented with vaginal discharge. PAP smears were repeatedly reported negative and an endometrial curettage 2 years prior to the diagnosis only showed fragments of benign squamous epithelium. Because of continuous symptoms a hysterectomy was performed and revealed extensive squamous metaplasia of the endometrium with focal transition to verrucous carcinoma. This case demonstrates that benign appearing squamous epithelium in curettage specimens, especially when abundant, is not necessarily ordinary portio epithelium. In this setting, the clinical presentation becomes paramount for considering a well differentiated squamous carcinoma of the endometrium and avoiding diagnostic delay.

Etiologic heterogeneity in endometrial cancer: evidence from a Gynecologic Oncology Group trial

OBJECTIVE

Although the epidemiology of typical endometrial carcinomas (grades 1-2 endometrioid or Type I) is well established, less is known regarding higher grade endometrioid or non-endometrioid carcinomas (Type II). Within a large Gynecologic Oncology Group trial (GOG-210), which included central pathology review, we investigated the etiologic heterogeneity of endometrial cancers by comparing risk factors for different histologic categories.

METHODS

Based on epidemiologic questionnaire data, risk factor associations, expressed as odds ratios (OR) with 95% confidence intervals (CI), were estimated comparing grade 3 endometrioid and Type II cancers (including histologic subtypes) to grades 1-2 endometrioid cancers.

RESULTS

Compared with 2244 grades 1-2 endometrioid cancers, women with Type II cancers (321 serous, 141 carcinosarcomas, 77 clear cell, 42 mixed epithelial with serous or clear cell components) were older; more often non-white, multiparous, current smokers; and less often obese. Risk factors for grade 3 endometrioid carcinomas (n=354) were generally similar to those identified for Type II cancers, although patients with grade 3 endometrioid tumors more often had histories of breast cancer without tamoxifen exposure while those with Type II tumors were more frequently treated with tamoxifen. Patients with serous cancers and carcinosarcomas more frequently had breast cancer histories with tamoxifen treatment compared to patients with other tumors.

CONCLUSIONS

Risk factors for aggressive endometrial cancers, including grade 3 endometrioid and non-endometrioid tumors, appear to differ from lower grade endometrioid carcinomas. Our findings support etiologic differences between Type I and II endometrial cancers as well as additional heterogeneity within Type II cancers.

Endometrial cancer risk factors by 2 main histologic subtypes: the NIH-AARP Diet and Health Study

On the basis of clinical and pathologic criteria, endometrial carcinoma has been distinguished as types I (mainly endometrioid) and II (nonendometrioid). Limited data suggest that these subtypes have different risk factor profiles. The authors prospectively evaluated risk factors for types I (n = 1,312) and II (n = 138) incident endometrial carcinoma among 114,409 women in the National Institutes of Health (NIH)-AARP Diet and Health Study (1995-2006). For individual risk factors, relative risks were estimated with Cox regression by subtype, and P(heterogeneity) was assessed in case-case comparisons with type I as the referent. Stronger relations for type I versus Type II tumors were seen for menopausal hormone therapy use (relative risk (RR) of 1.18 vs. 0.84; P(heterogeneity) = 0.01) and body mass index of ≥30 vs. <30 kg/m2 (RR of 2.93 vs. 1.83; P(heterogeneity) = 0.001). Stronger relations for type II versus type I tumors were observed for being black versus white (RR of 2.18 vs. 0.66; P(heterogeneity) = 0.0004) and having a family history of breast cancer (RR of 1.93 vs. 0.80; P(heterogeneity) = 0.002). Other risk factor associations were similar by subtype. In conclusion, the authors noted different risk factor associations for Types I and II endometrial carcinomas, supporting the etiologic heterogeneity of these tumors. Because of the limited number of Type II cancers, additional evaluation of risk factors will benefit from consortial efforts.

Application of Immunohistochemistry and Molecular Diagnostics to Clinically Relevant Problems in Endometrial Cancer Bojana Djordjevic, Shannon Westin, Russell R. Broaddus

A number of different clinical scenarios are presented in which lab-based analyses beyond the usual diagnosis based on light microscopic examination of H&E stained slides - immunohistochemistry and PCR-based assays such as sequencing, mutation testing, microsatellite instability analysis, and determination of MLH1 methylation - are most helpful for guiding diagnosis and treatment of endometrial cancer. The central goal of this information is to provide a practical guide of key current and emerging issues in diagnostic endometrial cancer pathology that require the use of ancillary laboratory techniques, such as immunohistochemistry and molecular testing. The authors present the common diagnostic problems in endometrial carcinoma pathology, types of endometrial carcinoma, description of tissue testing and markers, pathological features, and targeted therapy.

Gemcitabine for advanced endometrial cancer: a retrospective study of the Memorial sloan-Kettering Cancer Center experience

BACKGROUND

Gemcitabine is active in several gynecologic malignancies including ovarian cancer, cervical cancer, and uterine leiomyosarcoma. It has been used in an off-label setting for the treatment of advanced endometrial cancer, despite lack of published data showing efficacy. We performed a retrospective study to determine the progression-free survival and response rate of endometrial cancer patients treated with gemcitabine at Memorial Sloan-Kettering Cancer Center.

METHODS

Eligible patients had histologically confirmed advanced (stage IV or recurrent) endometrial cancer that was treated with single-agent gemcitabine at Memorial Sloan-Kettering Cancer Center between 1999 and 2009. Response to therapy was determined by review of computed tomography imaging by Response Evaluation Criteria in Solid Tumors 1.1 criteria.

RESULTS

Forty-six patients were included in the analysis. Median age was 66 years (range, 52-87 years). All patients were previously treated with chemotherapy. The median number of prior lines of chemotherapy was 2 (range, 1-8). Median dose of gemcitabine administered was 800 mg/m infused on days 1 and 8 of a 21-day cycle. Predominant histology was endometrioid (48%, n = 22) followed by serous (35%, n = 16), clear cell (15%, n = 7), and undifferentiated (2%, n = 1). Overall response rate was 10.9% (95% confidence interval, 1.9%-19.9%); 5 patients (11%) achieved a partial response. Thirteen patients (28%) displayed stable disease lasting at least 3 months. Of note, 5 (71%) of the 7 patients with clear cell histology displayed stable disease or partial response (n = 5). The median progression-free survival was 3.0 months (95% confidence interval, 2.1-3.3 months). Nonhematologic grades 3 and 4 toxicities were rare. Ten patients (22%) were treated with granulocyte colony-stimulating factor during treatment. Grade 3 thrombocytopenia was seen in 4 patients (9%). There were no cases of grade 4 thrombocytopenia.

CONCLUSIONS

In a mixed population of patients with previously treated advanced endometrial cancer, gemcitabine was well tolerated and showed modest activity. Patients with clear cell histology appeared to have greater likelihood of benefit.

Clear cell carcinoma of the female genital tract (not everything is as clear as it seems)

Clear cell carcinoma has a storied history in the female genital tract. From the initial designation of ovarian clear cell adenocarcinoma as "mesonephroma" to the linkage between vaginal clear cell carcinoma and diethylstilbestrol exposure in utero, gynecologic tract clear cell tumors have puzzled investigators, posed therapeutic dilemmas for oncologists, and otherwise presented major differential diagnostic challenges for pathologists. One of the most common errors in gynecologic pathology is misdiagnosis of clear cell carcinoma, on both frozen section and permanent section. Given the poor response to platinum-based chemotherapy for advanced-stage disease and increased risk of thromboembolism, accurate diagnosis of clear cell carcinoma is important in the female genital tract. This review (1) presents the clinical and pathologic features of female genital tract clear cell carcinomas; (2) highlights recent molecular developments; (3) identifies areas of potential diagnostic confusion; and (4) presents solutions for these diagnostic problems where they exist.

Endometrial carcinomas: a review emphasizing overlapping and distinctive morphological and immunohistochemical features

This review focuses on the most common diagnostic pitfalls and helpful morphologic and immunohistochemical markers in the differential diagnosis between the different subtypes of endometrial carcinomas, including: (1) endometrioid versus serous glandular carcinoma, (2) papillary endometrioid (not otherwise specified, villoglandular and nonvillous variants) versus serous carcinoma, (3) endometrioid carcinoma with spindle cells, hyalinization, and heterologous components versus malignant mixed müllerian tumor, (4) high-grade endometrioid versus serous carcinoma, (5) high-grade endometrioid carcinoma versus dedifferentiated or undifferentiated carcinoma, (6) endometrioid carcinoma with clear cells versus clear cell carcinoma, (7) clear cell versus serous carcinoma, (8) undifferentiated versus neuroendocrine carcinoma, (9) carcinoma of mixed cell types versus carcinoma with ambiguous features or variant morphology, (10) Lynch syndrome-related endometrial carcinomas, (11) high-grade or undifferentiated carcinoma versus nonepithelial uterine tumors. As carcinomas in the endometrium are not always primary, this review also discusses the differential diagnosis between endometrial carcinomas and other gynecological malignancies such as endocervical (glandular) and ovarian/peritoneal serous carcinoma, as well as with extra-gynecologic metastases (mainly breast and colon).