Morphologic Features of Gastric-type Cervical Adenocarcinoma in Small Surgical and Cytology Specimens

Gastric-type adenocarcinoma of the endocervix: Potentially overcoming resistant behavior with surgery

Objective

Gastric-type adenocarcinoma of the endocervix (GAS) is a rare form of human papillomavirus-independent cervical cancer commonly described as an insidious disease bearing a poor prognosis. Based on scarce data, uncertainty persists pertaining to its oncologic management.

Method

All cases of well-differentiated GAS treated at our institution from 2010 to 2021 were reviewed. Clinical characteristics, diagnostic tests results and oncologic outcomes were recorded and analyzed. Kaplan-Meier curves and log rank test were performed to compare survival curves between patients with tumors confined to the cervix (group 1: up to stage IB3) versus locally advanced or metastatic (group 2: stages II to IV).

Results

Cervical cytologies and biopsies yielded low detection rates (38 and 42% respectively) leading to 87% of patients with locally advanced or metastatic disease at diagnosis. Median overall survival (OS) was 40.0 ± 15.9 months with a clear dichotomy in survival when comparing patients with disease confined to the cervix to those with higher stages (respectively 59.0 vs 12.0 months, p = 0.047). None of the 5 patients initially managed with concurrent chemoradiotherapy (CCRT) responded to treatment but fortunately 3 of the latter achieved remission after surgery.

Conclusion

Well-differentiated GAS did not show favorable response to chemotherapy and radiation. Surgical resection seems to be a cornerstone in the management of this disease, as all patients who achieved remission were treated with surgery, either upfront or after suboptimal response to CCRT. We suggest considering aggressive upfront surgery when feasible. If CCRT is selected to avoid upfront exenterative procedures, rapid evaluation of tumor response is recommended.

Case Report: Pelvic mass and massive ascites as the first symptom in cervical adenocarcinoma: report of two cases and literature review

Cervical adenocarcinoma accounts for 10%-25% of total cases of cervical carcinoma. But in recent years, the incidence of adenocarcinoma has risen both proportionally and absolutely. Clinically, most cervical adenocarcinoma show no symptom or present with abnormal uterine bleeding or vaginal discharge, similar to squamous cell carcinoma. What different about it is that cervical cytological testing demonstrates a high false-negative rate of cervical adenocarcinoma, potentially leading to the failure in detecting in early stage. This report presents two cases both with pelvic masses, and massive ascites served as the initial symptom, which is similar to the clinical symptom of ovarian cancer, but ultimately diagnosed with cervical adenocarcinoma through surgical specimens. There are few literature reports on this situation. Hence, a literature review also has been performed to improve the recognition for cervical adenocarcinoma presenting with pelvic masses and massive ascites, and to avoid misdiagnosis.

Acute cervicitis resembling gastric-type mucinous adenocarcinoma that was definitively diagnosed by cervical conization: A case report

Although imaging studies are not typically performed for clinical diagnosis of cervicitis, in this case magnetic resonance imaging (MRI) was performed because a lesion with a tumor-like gross appearance was found in the uterine cervix. We present a case of cervicitis in which clinical, imaging and pathological features overlapped with those of gastric-type mucinous adenocarcinoma (GAS). The patient, a 30-year-old woman, was referred to a gynecologist with a complaint of watery vaginal discharge. On visual examination, the uterine cervix was irregularly enlarged and bled easily, suggesting cervical cancer. The next day, the patient had a fever of 39°C and blisters appeared on her vulva due to herpes simplex virus type II infection. MRI showed a diffusely enlarged cervix with poorly marginated high signal intensity on T2-weighted imaging (WI) and apparent diffusion coefficient map as well as strong enhancement on contrast-enhanced T1WI, which are findings consistent with GAS. Although a punch biopsy showed only mild atypia of the cervical glands, this was not enough to completely rule out GAS. Consequently, laser conization of the lesion was performed for definitive diagnosis, and the diagnosis of cervicitis was made. Acute cervicitis can be difficult to differentiate from GAS based on symptoms, results of cervical biopsy and MR imaging because of their overlapping features. Even when a patient presents with a lesion with tumor-like gross appearance, acute cervicitis should be included in the differential diagnosis if the result of cervical biopsy is negative, especially when accompanied by infection-like fever.

Case Report: A rare case of gastric-type adenocarcinoma of stumps of duplicated cervices in a 49-year-old woman: A case with hidden focus confused us a lot

Gastric-type endocervical adenocarcinoma (G-EAC) is a rare special type of cervical mucinous adenocarcinomas, and it is reported the incidence is unrelated to human papilloma virus infection. We report a rare case of G-EAC in stumps of duplicated cervices in a 49-year-old female patient. The woman complained of post-coital bleeding. She had a didelphic uterus with a duplex cervix, and had undergone subtotal hysterectomy 16 years ago. Gynecological examination revealed a normal-appearing right cervix, but the non-dominant side of the left cervix, which was buried and covered by the side wall of the left vagina, was difficult to view. After exposing, the left side cervix presented a mature appearance which was smaller than a normal cervix. Her serum carbohydrate antigen-19-9 levels was 112.59 U/ml. The right cervix's cytology was normal, whereas the left cervix had unusual glandular epithelial cells. HPV testing on both cervical smears was negative. Adenocarcinoma was identified at 3, 6, 12 o'clock at the right cervix in a colposcopy-directed punch biopsy, while no abnormality was found in the biopsy of the left cervix, nor in the curettage of the double cervices. Pelvic magnetic resonance imaging (MRI) revealed two cervical canals, with a 1.9cm×1.6cm mass inside the left cervix, and the left wall of the right cervix may be involved by the tumor of the left cervix. After much deliberation, we considered that the patient had adenocarcinoma of the left cervix stage IB1. Then, the patient underwent radical cervical resection with bilateral salpingo-oophorectomy and bilateral pelvic lymphadenectomy. Her final histopathology indicated G-EAC of the duplicated cervices. After surgery, she received concurrent chemoradiation. Currently, 29 months after the final chemotherapy was administered, the patient remains healthy. Because G-EAC with duplicated cervices is an uncommon cunning tumor with a bad prognosis, early identification and therapy are recommended to enhance the prognosis. The comprehensive evaluation of symptoms and gynecological examination with cervical cytology, colposcopy-directed punch biopsy, endocervical curettage and MRI examine together may assist in determining an accurate preoperative diagnosis.

Gastric-type adenocarcinoma of the cervix in patients with Peutz-Jeghers syndrome: a systematic review of the literature with proposed screening guidelines

OBJECTIVES

To perform a systematic review of gastric-type adenocarcinoma of the cervix and lobular endocervical glandular hyperplasia (a possible precursor lesion) in Peutz-Jeghers syndrome, and to analyze data from the literature, along with our institutional experience, to determine recommendations for screening and detection.

METHODS

A comprehensive literature searc and retrospective search of pathology records at our institutio were conducted. Articles were screened by two independent reviewers. Case reports/series on lobular endocervical glandular hyperplasia/gastric-type adenocarcinoma of the cervix in Peutz-Jeghers syndrome were included. Demographic, clinical, and radiologic information was collected.

RESULTS

A total of 1564 publications were reviewed; 38 met the inclusion criteria. Forty-nine were included in the analysis (43 from the literature, 6 from our institution). Forty-three reported on gastric-type adenocarcinoma alone, 4 on lobular endocervical glandular hyperplasia alone, and 2 on concurrent lobular endocervical glandular hyperplasia/gastric-type adenocarcinoma. Median age at diagnosis was 17 (range, 4-52) for patients with lobular endocervical glandular hyperplasia alone and 35 (range, 15-72) for those with gastric-type adenocarcinoma. The most common presenting symptoms were abdominal/pelvic pain and vaginal bleeding/discharge. Imaging was reported for 27 patients; 24 (89%) had abnormal cervical features. Papanicolaou (Pap) smear prior to diagnosis was reported for 12 patients; 6 (50%) had normal cytology, 4 (33%) atypical glandular cells, and 2 (17%) atypical cells not otherwise specified. Patients with gastric-type adenocarcinoma (n=45) were treated with surgery alone (n=16), surgery/chemotherapy/radiation (n=11), surgery/chemotherapy (n=9), surgery/radiation (n=5), or radiation/chemotherapy (n=4). Twelve (27%) of 45 patients recurred; median progression-free survival was 10 months (range, 1-148). Twenty patients (44%) died; median overall survival was 26 months (range, 2-156). Thirteen patients (27%) were alive with no evidence of disease.

CONCLUSIONS

Gastric-type adenocarcinoma in Peutz-Jeghers syndrome is associated with poor outcomes and short progression-free and overall survival. Screening recommendations, including pathognomonic symptom review and physical examination, with a low threshold for imaging and biopsy, may detect precursor lesions and early-stage gastric-type adenocarcinoma, leading to better outcomes in this high-risk population.

PROSPERO REGISTRATION NUMBER

CRD42019118151.

Navigating through perplex morphologic changes after exogenous hormone usage

Clinical application of exogenous hormone as a method of contraception and/or treatment of various gynecologic disorders is exceedingly common. Unfortunately, the concurrent use of these agents also complicates the interpretation of pathology specimens. Various studies have shown that morphologic changes induced by hormonal therapies are present in both non-neoplastic and neoplastic tissues within the women's reproductive tract. It is important to understand the exogenous hormone induced morphologic changes, as it helps the pathologists make the accurate diagnosis, and in turn, guide clinicians to make optimal clinical decisions. In this review, we summarize the morphologic changes in both neoplastic and non-neoplastic endometrial, cervical, and myometrial surgical specimens after hormonal therapies, particularly after progestin treatment. In the endometrium, particularly in the scenario of progestin-treated atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia (AEH/EIN), there is notoriously poor interobserver agreement and difficulty in assessing for the residual disease. We summarize current literature and propose our recommended approach in assessing these challenging endometrial biopsies, including a diagnostic algorism, the use of PAX-2, PTEN, beta-catenin immunohistochemistry panel, as well as consistency in diagnostic wording of the report. In the cervix, progestin makes dysplastic lesions appear metaplastic, thus high-grade squamous dysplastic lesions may be easily missed. Within the myometrium, lesions such as adenomyosis may show various degree of decidualization, while smooth muscle neoplasms may show apoplectic changes, and stromal lesions including endometrial stromal sarcoma may show more eosinophilic cytoplasm. All such changes may pose more or less diagnostic challenges in our daily practice. However, most are readily recognizable when we understand particular hormone related scenarios.

A retrospective study on incidence, diagnosis, and clinical outcome of gastric-type endocervical adenocarcinoma in a single institution

Background

Gastric-type endocervical adenocarcinoma is rare but the most common subtype of cervical adenocarcinoma not associated with human papillomavirus. It is more aggressive with a shorter five-year survival rate compared to human papillomavirus-associated usual type endocervical adenocarcinoma. The objectives of our study were to determine the incidence and clinical-pathological characteristics of Gastric-type endocervical adenocarcinoma in a single institution.

Methods

Twenty four cases of invasive cervical adenocarcinoma were identified between January 2000 and December 2015, from the Saskatoon Health Region pathology database using International Endocervical Adenocarcinoma Criteria and Classification to retrospectively classify endocervical adenocarcinoma. Immunohistochemistry was performed with antibodies for Gastric mucin-6 (MUC-6), p16^INK4a, cyclin-dependent kinase inhibitor 2A (p16), p53 protein (p53), estrogen and progesterone receptors. Clinical and pathological data was retrieved from pathology reports and charts. Statistical analysis was performed using Mann-Whitney U test and Chi-Square test.

Results

Using the International Endocervical Adenocarcinoma Criteria and Classification criteria, 19 cases (79.2%) were classified as human papillomavirus-associated usual type endocervical adenocarcinoma, and five cases (20.8%) as Gastric-type endocervical adenocarcinoma. In our study 40% of Gastric-type endocervical adenocarcinoma cases presented at stage III compared to none of the usual type endocervical carcinoma cases. All the Gastric-type endocervical adenocarcinoma cases were positive for MUC-6, and negative for p16. 60% Gastric-type endocervical adenocarcinoma cases demonstrated mutant type p53 staining. In contrast, 84.2% of human papillomavirus-associated usual type endocervical adenocarcinoma cases showed block like nuclear and cytoplasmic positivity with p16 antibodies. The Gastric-type endocervical adenocarcinoma group had significantly shorter median survival time than human papillomavirus-associated usual type endocervical adenocarcinoma group, Gastric-type endocervical adenocarcinoma is 22 months compared to human papillomavirus-associated usual type endocervical adenocarcinoma at 118 months (p = 0.043).

Conclusions

In this study, Gastric-type endocervical adenocarcinoma accounted for 20.8% of all cervical adenocarcinoma with higher stage at presentation and shorter overall survival. Criteria proposed by International Endocervical Adenocarcinoma Criteria and Classification (IECC) are simple and reproducible in differentiating between, HPV- associated (HPVA) and non HPV associated (NHPVA) endocervical adenocarcinoma. Although none of the IHC assays is specific for GAS, but p16, MUC-6, ER, PR and p53 may further aid in confirming GAS and to differentiate it from benign and malignant mimics.

Massively parallel sequencing analysis of 68 gastric-type cervical adenocarcinomas reveals mutations in cell cycle-related genes and potentially targetable mutations

Gastric-type cervical adenocarcinoma (GCA) is an aggressive type of endocervical adenocarcinoma characterized by mucinous morphology, gastric-type mucin, lack of association with human papillomavirus (HPV) and resistance to chemo/radiotherapy. We characterized the landscape of genetic alterations in a large cohort of GCAs, and compared it with that of usual-type HPV-associated endocervical adenocarcinomas (UEAs), pancreatic adenocarcinomas (PAs) and intestinal-type gastric adenocarcinomas (IGAs). GCAs (n = 68) were subjected to massively parallel sequencing targeting 410-468 cancer-related genes. Somatic mutations and copy number alterations (CNAs) were determined using validated bioinformatics methods. Mutational data for UEAs (n = 21), PAs (n = 178), and IGAs (n = 148) from The Cancer Genome Atlas (TCGA) were obtained from cBioPortal. GCAs most frequently harbored somatic mutations in TP53 (41%), CDKN2A (18%), KRAS (18%), and STK11 (10%). Potentially targetable mutations were identified in ERBB3 (10%), ERBB2 (8%), and BRAF (4%). GCAs displayed low levels of CNAs with no recurrent amplifications or homozygous deletions. In contrast to UEAs, GCAs harbored more frequent mutations affecting cell cycle-related genes including TP53 (41% vs 5%, p < 0.01) and CDKN2A (18% vs 0%, p = 0.01), and fewer PIK3CA mutations (7% vs 33%, p = 0.01). TP53 mutations were less prevalent in GCAs compared to PAs (41% vs 56%, p < 0.05) and IGAs (41% vs 57%, p < 0.05). GCAs showed a higher frequency of STK11 mutations than PAs (10% vs 2%, p < 0.05) and IGAs (10% vs 1%, p < 0.05). GCAs harbored more frequent mutations in ERBB2 and ERBB3 (9% vs 1%, and 10% vs 0.5%, both p < 0.01) compared to PAs, and in CDKN2A (18% vs 1%, p < 0.05) and KRAS (18% vs 6%, p < 0.05) compared to IGAs. GCAs harbor recurrent somatic mutations in cell cycle-related genes and in potentially targetable genes, including ERBB2/3. Mutations in genes such as STK11 may be used as supportive evidence to help distinguish GCAs from other adenocarcinomas with similar morphology in metastatic sites.

HPV-Negative Cervical Cancer: A Narrative Review

Cervical cancer (CC) is the fourth most frequent cancer in women worldwide. HPV infection is associated with the majority of CC cases, but a small proportion of CCs actually test negative for HPV. The prevalence of HPV among CC histotypes is very different. It has been suggested that HPV-negative CC may represent a biologically distinct subset of tumors, relying on a distinct pathogenetic pathway and carrying a poorer prognosis, than HPV-positive CCs. Although, the discordance in terms of sensitivity and specificity between different HPV tests as well as the potential errors in sampling and storing tissues may be considered as causes of false-negative results. The identification of HPV-negative CCs is essential for their correct management. The aim of this narrative review is to summarize the clinical and pathological features of this variant. We also discuss the pitfalls of different HPV tests possibly leading to classification errors.

Secondary Involvement of the Uterine Cervix by Nongynecologic Neoplasms: A Detailed Clinicopathologic Analysis

Secondary involvement of the uterine cervix by nongynecologic neoplasms is rare accounting for <2% of metastases to the gynecologic tract. This study aimed to analyze the clinicopathologic features of cervical involvement by nongynecologic malignancies. A total of 47 cases were identified including 39 (83%) carcinomas, 6 lymphomas (12.8%), and 2 (4.2%) cutaneous malignant melanomas. The most common primary site of origin among carcinomas was the gastrointestinal tract (27, 69.2%), followed by breast and urothelium (5 each, 12.8%), gallbladder, and lung (1 each, 2.6%). The gynecologic tract was involved at the presentation in 16 patients (34%), including 5 (10.6%) with the cervix being the first site, 7 (14.9%) with synchronous involvement of the cervix and other gynecologic sites, and 4 (8.5%) with the involvement of other gynecologic sites before the cervical presentation. Patients with lymphoma were younger compared with those with carcinoma (43.7 vs. >50.5) (P=0.01). Mean time to identification of cervical metastases was <1 year for gallbladder carcinoma, melanomas, and gastrointestinal signet ring cell carcinomas (P=0.03). Features that varied with different types of metastatic tumor included lymphovascular space invasion, depth of stromal invasion, growth pattern (glands lacking architectural complexity, cribriforming, solid), presence of goblet cells, and signet ring cells, degree of cytologic atypia, and overall findings mimicking a benign/noninvasive process (P≤0.027). Six tumors (12.8%) were initially misdiagnosed as cervical primary. Metastatic nongynecologic tumors can mimic primary in situ or invasive neoplasms in both ectocervix and endocervix. In patients with a known prior malignancy, the clinical history with ancillary studies and a high level of suspicion are crucial to ensure accurate diagnosis.

[Cytological findings in glandular lesions of the uterine cervix]

BACKGROUND

Due to further developments in the diagnosis of glandular cervical changes with the definition of several new entities, the exact classification of these can only be achieved with the help of cytomorphology and additive methods.

OBJECTIVES AND METHODS

The aim of this work is to give an overview of the status and future perspectives of cytomorphological diagnostics and biomarkers in this setting. Our own expertise and literature data were considered and evaluated. We especially covered the benign group including microglandular hyperplasia, tubal metaplasia, and reactive withdrawal induced changes, as well as adenocarcinoma in situ of usual type and invasive adenocarcinoma of usual type.

RESULTS AND CONCLUSIONS

Immunocytochemical markers may occasionally take a role in the evaluation of benign endocervical glandular proliferations, the mainstay of their interpretation occurs morphologically in the conventional routinely stained smears. Adenocarcinoma in situ of usual type has very characteristic cytological criteria, which are reproducible in daily work, and p16 positivity is a very useful marker for this HPV-related lesion. The present classification of invasive adenocarcinomas of the endocervix requires knowledge of new immunohistochemical and molecular technologies. Due to HPV vaccination we can expect a decrease of HPV associated adenocarcinomas and a relative increase of HPV negative, clinically more aggressive adenocarcinomas. The cytological features of some groups of non-HPV-associated adenocarcinomas are not specific. In these instances, the different biomarkers are more helpful.

Cytomorphologic Features of Gastric-Type Endocervical Adenocarcinoma in Liquid-Based Preparations

OBJECTIVE

Gastric-type endocervical adenocarcinoma (GAS) is a recently described, uncommon, and aggressive tumor with distinct morphologic features and HPV-independent etiology. Data on GAS in liquid-based cytology (LBC) Papanicolaou (Pap) test preparations from a North American patient population are scant. We systematically assessed the cytomorphologic characteristics of GAS in LBC from patients in Ontario and examined if glandular cell nuclear area could represent a readily assessable feature which may aid in GAS detection.

STUDY DESIGN

Pap test slides preceding the diagnosis of GAS were retrieved locally or requested from outside laboratories. A structured review of 15 cytomorphologic features was performed using the available LBC Pap test slides of GAS and a set of usual-type endocervical adenocarcinomas (UEA). Morphometry of the glandular cell nuclear area was performed, and normalized values were compared to UEA and benign endocervical cells.

RESULTS

At least 1 Pap test (5 ThinPrep®, 11 SurePath®, and 1 direct smear) was available for 14 patients. Original LBC Pap test diagnoses were negative for intraepithelial lesion or malignancy (NILM) (7), adenocarcinoma/carcinoma (6), atypical glandular cells (2), and adenocarcinoma in situ (1). Review detected abnormal glandular cells in 6/7 NILM cases. Honeycomb-like sheets, nuclear enlargement, and microvesicular cytoplasm were the single most common architectural, nuclear, and cytoplasmic features, respectively. Microvesicular cytoplasm (100 vs. 17%), honeycomb-like sheets (87 vs. 8%), prominent nucleoli (93 vs. 25%), and anisonucleosis (93 vs. 50%) were most discriminatory for GAS versus UEA, respectively. Yellow mucin, intranuclear cytoplasmic pseudoinclusions, and goblet/Paneth-like cells were uncommon, but unique for GAS. Glandular cell nuclear area normalized to neutrophils was found to be significantly increased in GAS compared to benign endocervical cells.

CONCLUSIONS

GAS is under-recognized and may mimic reactive endocervical cells. Awareness of the tumor type and its cytomorphology is critical for early detection. Identification of glandular cells with uniform nuclear enlargement in conjunction with any of the other cytologic features may help avoid false-negative Pap results. Neutrophils may serve as convenient size reference and visual aid.

Uncommon Cervical Lesions: A Review and Discussion of the Differential Diagnosis

CONTEXT.—

While the vast majority of cervical tumors consist of human papillomavirus (HPV)-related squamous cell carcinoma or adenocarcinoma, a subset of rare tumor types, frequently unrelated to HPV, does occur in this location. These tumors vary widely in prognostic and therapeutic implications, and accurate recognition is crucial to providing appropriate treatment. Some are benign or portend a favorable prognosis (adenoid basal carcinoma, ectopic prostate tissue), while others are frankly malignant lesions with a less favorable prognosis (adenoid cystic carcinoma, HPV-negative endocervical adenocarcinoma, mesonephric adenocarcinoma, clear cell carcinoma, small cell carcinoma, and adenosquamous carcinoma).

OBJECTIVE.—

To review the morphologic features of uncommon cervical lesions, the utility of immunohistochemistry for distinction between these entities, and the clinical and prognostic implications of accurate diagnosis.

DATA SOURCES.—

University of Michigan cases and review of the pertinent literature regarding the entities described.

CONCLUSIONS.—

Key morphologic and immunohistochemical features detailed herein will allow for the accurate distinction between these uncommon cervical lesions. Morphology is most useful in discriminating between the entities, as there is frequent immunohistochemical overlap between them; however, in rare instances immunohistochemistry can be useful in resolving the diagnosis.

Gastric-type endocervical adenocarcinoma and cervical cytology: Experience at a general hospital and review of the literature

INTRODUCTION

Gastric-type endocervical adenocarcinoma (GAS) is an uncommon type of endocervical adenocarcinoma that is not associated with human papillomavirus infection. This diagnosis is relatively rare and may portend a worse prognosis than usual-type endocervical adenocarcinoma. Subtle morphological features make it an under-recognised diagnostic challenge. Study of the cytological features of individual cases is valuable in order to increase awareness of this entity.

METHODS

The pathology database of our institution was searched for the diagnosis of GAS and all cytological and surgical specimens for each patient were reviewed. The original cytological interpretation was compared to a retrospective central review interpretation. Clinical history and follow-up results were obtained from the electronic medical record.

RESULTS

Four cases of GAS were identified. The findings on initial cervical cytology varied, with GAS found in both patients with negative cervical cytology and those with atypical glandular cells. Cytological findings included endocervical cells arranged in three-dimensional clusters and honeycomb sheets with abundant vacuolar cytoplasm, and in two patients, moderate nuclear atypia with irregular nuclear membranes, coarse chromatin, hyperchromatic nuclei, and prominent nucleoli. In one patient, GAS was incidentally discovered via thorough sampling of a cystic lesion in the superior portion of the endocervical canal.

CONCLUSIONS

GAS is an aggressive human papillomavirus-independent type of endocervical adenocarcinoma with subtle morphological features and, as our study shows, varying clinical presentation. Given the aggressive nature of GAS and the difficulties in initial diagnosis, increased awareness of this entity among pathologists is crucial.

Immunohistochemical expression of HIK1083 and MUC6 in endometrial carcinomas

AIMS

Gastric-type endocervical adenocarcinoma (EA) is characterised by aggressive behaviour and pathogenesis independent of human papillomavirus infection. Because of its morphology and frequent mutation-pattern expression of p53, gastric-type EA may be confused with several types of endometrial carcinoma, particularly in biopsy and curettage specimens. HIK1083 and MUC6 are immunohistochemical markers used to support a diagnosis of gastric-type EA; however, the rates of expression of these markers in endometrial tumours are largely unknown. We therefore aimed to assess the expression of HIK1083 and MUC6 in a cohort of different types of endometrial carcinoma.

METHODS AND RESULTS

Ninety-one endometrial carcinomas (56 endometrioid, 16 clear cell, and 19 serous) from 91 patients treated with hysterectomy were included. A representative tumour block from each case was used for immunohistochemical staining with HIK1083 and MUC6. The percentage of stained cells (0-100%) and average staining intensity (weak, moderate, and strong) were recorded for both markers. None of 91 cases expressed HIK1083. In contrast, 66% (60/91) of cases showed at least focal expression of MUC6; importantly, 54 of 60 (90%) positive cases showed moderate or strong staining. Five of 60 (8%) cases showed MUC6 staining in ≥50% of tumour cells. Endometrioid tumours (49/56, 88%) were more likely to express MUC6 than cases of clear cell (1/16, 6%) or serous (10/19, 53%) carcinoma.

DISCUSSION

Endometrial carcinoma often expresses MUC6. In contrast, HIK1083 is consistently negative, and thus, when positive, is a more reliable marker for distinguishing gastric-type EA from some of its endometrial mimics.