False-Negative Interpretation of Adenocarcinoma In Situ in the College of American Pathologists Gynecologic PAP Education Program

Pitfalls in Gynecological Cytology: Review of the Common and Less Frequent Entities in Pap Test

BACKGROUND

Pitfalls in Pap test could be defined as false positive, false negative, or underdiagnosed results which can lead to unnecessary diagnostic procedures or delayed and inadequate treatment. It can be a consequence of misinterpretation of certain morphological entities which are described in this paper.

SUMMARY

The paper presents an overview of the morphological features and look-alikes of the common sources of pitfalls such as atrophy, repair, intrauterine device change, tubal metaplasia, hyperchromatic crowded groups, and radiation changes. Rare causes of pitfalls such as Arias-Stella changes, pemphigus, tumor diathesis per se, rare types of cervical cancer, including verrucous and papillary squamous cell cancer, gastric type, and endometrioid adenocarcinoma are also described.

KEY MESSAGES

The awareness of pitfalls in cervical cytology is important for cytopathologists and clinicians to avoid future errors. Review of Pap tests with erroneous diagnosis is important for quality control in cytology laboratory, and it must be considered an educational- and experience-building procedure. Cytopathologist should not pull back in significant diagnoses, especially in human papillomavirus-negative cases.

Challenging lesions in cervical cytology: The elusive HSIL

Cervical cytology has been an integral part of cervical cancer screening since the mid-20th century with the implementation of screening protocols utilising Pap testing. During that time, cervical cancer has gone from the leading cause of cancer deaths in women to not even appearing in the top 10 causes of US cancer deaths. However, despite its long and widespread use, cervical cytology remains a diagnostically challenging area in the practice of cytopathology. Of particular importance for diagnosticians is the accurate diagnosis of high-grade squamous intraepithelial lesions (HSILs), given the significant risk of progression to invasive cervical cancer and the importance to patient management. Therefore, this review is presented in order to highlight the diagnostic features of HSIL, its various appearances, and important benign and neoplastic differential considerations with an emphasis on morphological clues that can aid in distinguishing between these different processes.

Disparities in Diagnosis and Treatment of Cervical Adenocarcinoma Compared With Squamous Cell Carcinoma: An Analysis of the National Cancer Database, 2004-2017

OBJECTIVES

The aim of the study are to compare trends in diagnosis and treatment of adenocarcinoma of the cervix (AC) to squamous cell carcinoma of the cervix (SCC) and to examine associations between stage at diagnosis and guideline-concordant treatment with race, age, and insurance type for AC and SCC.

MATERIALS AND METHODS

We performed a retrospective cohort study of cervical AC ( n = 18,811) and SCC ( n = 68,421) from the 2004-2017 National Cancer Database. We used generalized linear models to evaluate trends in frequency of histologies and to evaluate associations between race, age, and insurance status with stage of diagnosis and receipt of National Comprehensive Cancer Network guideline-concordant treatment for AC and SCC.

RESULTS

The proportion of AC relative to SCC increased from 19.4% (95% CI = 18.4-20.5) to 23.2% (95% CI = 22.2-24.2) from 2004 to 2017 ( p < .001). Compared with SCC, women with AC were younger, more likely to be White, and privately insured ( p < .001). Older women with AC were 44% less likely to be diagnosed with early-stage disease than younger women (adjusted relative risk = 0.56, 95% CI = 0.52-0.60); there was no significant difference for SCC. Black women with AC were 16% less likely to be diagnosed with early-stage disease (adjusted relative risk [aRR] = 0.84, 95% CI = 0.79-0.89) than White women. Women with public insurance were less likely to be diagnosed at an early stage for both AC (aRR = 0.81, 95% CI = 0.78-0.84) and SCC (aRR = 0.79, 95% CI = 0.77-0.81). Rates of guideline-concordant treatment were similar for AC and SCC, with minimal differences by age, race, and insurance.

CONCLUSIONS

As the proportion of AC to SCC rises, important race and age-related disparities must be addressed to reduce unnecessary morbidity and death.

False-negative Papanicolaou tests in women with biopsy-proven invasive endocervical adenocarcinoma/adenocarcinoma in situ: a retrospective analysis with assessment of interobserver agreement

INTRODUCTION

The objectives of our study were to identify factors contributing to false-negative Papanicolaou (Pap) tests in patients with endocervical adenocarcinoma (EA) or adenocarcinoma in situ (AIS), and to analyze the impact of educational instruction on interobserver agreement in these cases.

MATERIALS AND METHODS

False-negative Pap tests from patients with EA/AIS were reviewed by a consensus group and by 12 individual reviewers in 2 rounds, with an educational session on glandular neoplasia in Pap tests conducted between the 2 rounds.

RESULTS

Of 79 Pap tests from patients with EA/AIS, 57 (72.2%) were diagnosed as abnormal and 22 (27.8%) as negative. Of the 22 false-negative cases, 10 remained negative on consensus review, with false-negative diagnoses attributed to sampling variance. The other 12 cases were upgraded to epithelial abnormalities (including 8 to glandular lesions). The false-negative diagnoses were attributed to screening variance in 2 cases and interpretive variance in 10 cases. On individual review, abnormal cells were misinterpreted as reactive glandular cells or endometrial cells in 7 of 8 and 5 of 8 cases upgraded to glandular abnormalities, respectively. With education, the proportion of individual reviewers demonstrating at least moderate agreement with the consensus diagnosis (Cohen's kappa >0.4) increased from 33% (4 of 12) to 75% (9 of 12).

CONCLUSIONS

Sampling and interpretive variance each accounted for nearly one-half of the false-negative Pap tests, with underclassification as reactive glandular or endometrial cells the main source of the interpretive variances. Educational instruction significantly decreased the interpretive variance and interobserver variability in the diagnosis of glandular abnormalities.

Endocervical adenocarcinoma in situ-from Papanicolaou test to hysterectomy: a series of 74 cases

INTRODUCTION

Endocervical adenocarcinoma in situ (AIS) is not always identified on cervical Papanicolaou (Pap) test cytology because the Pap test has relatively low sensitivity for the diagnosis endocervical glandular lesions. We performed a retrospective study to determine the relative sensitivity of different diagnostic approaches, including Pap tests, cervical biopsy and/or endocervical curettage, loop electrosurgical excision procedure (LEEP), and hysterectomy specimens.

METHODS

Cases of endocervical AIS diagnosed from August 2005 to January 2019 were retrieved from our institution's pathology databases, and their clinicopathologic features were reviewed.

RESULTS

A total of 74 patients with endocervical AIS with or without concurrent squamous intraepithelial lesions or cervical neoplasms were identified. Their mean age at diagnosis was 39.9 years. More than one half of the cases of AIS were not detected from screening Pap tests but were diagnosed during histologic examination of cervical biopsy or endocervical curettage, LEEP, or cone biopsy specimens (~66%). Only a few patients had had a definitive diagnosis of AIS from the Pap tests (10.8%). Other abnormal glandular cytology included atypical glandular cells, not otherwise specified (16.2%), atypical glandular cells favoring neoplasia (5.4%), and atypical glandular cells suspicious for malignancy (1.3%). Abnormal squamous cytology was common in the study population (54%), with high-grade squamous intraepithelial lesion the most common finding (30%). AIS was diagnosed in 31 of 42 cervical biopsies or curettages, with 16 cases an incidental finding and 15 cases confirming previous abnormal glandular cytology. In addition, AIS was identified in 51 of 53 LEEPs. Approximately 41.5% of those undergoing LEEP had a previous diagnosis of AIS, and 54.7% of the cases were incidental findings. More than one half of the AIS cases harbored significant concurrent cervical lesions, including 26.7% with high-grade squamous intraepithelial lesion, 5.7% with low-grade squamous intraepithelial lesion, 1.9% with invasive squamous cell carcinoma, 20.9% with invasive adenocarcinoma, and 6.7% with microinvasive adenocarcinoma.

CONCLUSIONS

Our results have demonstrated that the ability to detect AIS with routine screening Pap testing or biopsy/curettage has variable efficacy depending on the screening methods. Given the relatively low combined sensitivity of Pap testing and biopsy/endocervical curettage in the diagnosis of AIS, all LEEPs and cervical cone biopsies performed for squamous cell abnormalities should be thoroughly evaluated for glandular lesions.

Interpretation pitfalls and malignant mimics in cervical cytology

Cervical cytology has remained a diagnostically challenging area despite its long and widespread use. At least part of this challenge has stemmed from the cytomorphologic overlap between benign and neoplastic processes. The present review has highlighted select benign processes that present diagnostic pitfalls. For each of these, we have discussed the pertinent cytologic features and emphasized the morphologic clues that will aid in distinguishing the benign entities from the neoplastic processes they mimic.

The Differential Diagnosis of Reparative Changes and Malignancy: Performance in the College of American Pathologists Pap Education and Proficiency Testing Programs

Context.—

Repair is a challenging diagnosis and a significant source of false-positive (FP) interpretations in cervical cytology. No large-scale study of performance of repair in the liquid-based era has been performed.

Objective.—

To evaluate the performance of repair in the College of American Pathologists Pap Education and Proficiency Testing (PT) programs.

Design.—

The FP rate for slides classified as repair was evaluated by preparation type, participant type (cytotechnologist, pathologist, or laboratory), and program. The specific misdiagnosis category and individual slide performance were also evaluated. The rate of misclassification of slides as repair by participants for other diagnostic categories in the Pap Education program was assessed.

Results.—

The overall FP rate was 1700 of 12 715 (13.4%). There was no significant difference by program or preparation type. Within the Education program there was no difference by participant type, but pathologists' FP rate in the PT program (47 of 514, 9.1%) was significantly better than cytotechnologists in the PT program (51 of 380, 13.4%) and pathologists in the Education program (690 of 4900, 14.1%). High-grade squamous intraepithelial lesions/cancers (HSIL+) accounted for 1380 of 1602 FP interpretations (86%) in Education, but 43 of 98 (43.9%) in PT. Most slides had a low rate of misclassification, but a small number were poor performers. False-negative diagnosis of HSIL+ as repair was less common, ranging from 0.7% to 1.8%.

Conclusions.—

Despite initial indications that liquid-based cytology might reduce the rate of misclassification of repair, FP interpretations remain common and are no different by preparation type. Misclassification is most commonly as HSIL or carcinoma, potentially resulting in significant patient harm.

Trends in cervical cancer incidence rates by age, race/ethnicity, histological subtype, and stage at diagnosis in the United States

Recent trends of cervical cancer incidence by histology and age in the United States (U.S.) have not been reported. We examined contemporary trends in cervical squamous cell carcinoma (SCC) and adenocarcinoma (AC) incidence rates in the U.S. by age group, race/ethnicity, and stage at diagnosis after accounting for hysterectomy. Incidence data (1999-2015) were obtained from the U.S. Cancer Statistics Incidence Analytic Database. Hysterectomy prevalence was estimated using National Health Interview Survey data (2000-2015). Overall SCC incidence rates continued to decrease in all racial/ethnic groups except among non-Hispanic whites in whom rates stabilized in the 2010s, largely driven by stable trends in ages <50 years and a slower pace of decrease in ages 50-59 years. After a stable trend between 1999 and 2002, AC incidence rates among non-Hispanic whites rose during 2002-2015 (1.3% per year), mostly due to increases in ages 40-49 (4.4% annually since 2004) and 50-59 years (5.5% annually since 2011). Overall AC incidence rates during 1999-2015 decreased in blacks and Hispanics but were stable in Asian/Pacific Islanders; in all these race/ethnicities, rates were generally stable in ages <50 years but decreasing in older ages. Rates of distant stage cervical SCC and AC among non-Hispanic whites increased in several age groups but were generally stable in non-whites. Increasing or stabilized incidence trends for AC and attenuation of earlier declines for SCC in several subpopulations underscore the importance of intensifying efforts to reverse the increasing trends and further reduce the burden of cervical cancer in the U.S.

Challenges in the Pap diagnosis of endocervical adenocarcinoma in situ

INTRODUCTION

Recognition of adenocarcinoma in situ (AIS) in cervical cytology is challenging.

MATERIALS AND METHODS

We calculated the sensitivity and accuracy of Papanicolaou (Pap) tests obtained within 1 year of a histologic diagnosis of AIS from 2007 to 2016. We also correlated it with the coexistence of squamous lesions, calculated the interobserver agreement, and compared these measures with those of endocervical adenocarcinoma (ECCA). We correlated AIS detection with high-risk human papillomavirus (hrHPV) status.

RESULTS

Of 72 patients with histologic AIS and 48 patients with ECCA, 92% and 87.5%, respectively, had abnormal Pap test results. A glandular abnormality was detected in 44.4% of the AIS and 77.1% of the ECCA cases. Complete cytohistologic concordance was reached in 8.3% of AIS and 22.9% of ECCA cases. In addition, 27.8% of AIS and 6.3% of ECCA cases were diagnosed on Pap as a high-risk squamous abnormality. Concurrent squamous lesions were present in 79.2% of patients with AIS and 29.2% of patients with ECCA. The Paps from the AIS and ECCA cases were diagnosed as pure squamous abnormalities in 47.2% and 10.4% of cases, respectively. In the AIS cases, interobserver agreement was substantial for detection of any high-risk cytologic abnormality (kappa = 0.67) and fair for detection of any glandular abnormality (kappa = 0.34). Among the 26 patients with AIS tested for hrHPV, 92% had positive results and 8% had negative results.

CONCLUSIONS

The cytologic sensitivity for the detection of AIS remains low. It is directly related to the coexistence of squamous lesions. Cytology and hrHPV as stand-alone screening tests fail in the early detection of a small proportion of glandular lesions, although combined testing will improve their detection rates.