Evaluation and significance of hyperchromatic crowded groups (HCG) in liquid-based paps

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.

Can Mitotic Figures in Hyperchromatic Crowded Groups be Cytodiagnostic Criteria for High-Grade Squamous Intra-epithelial Lesions?

Aims

The present study aimed to investigate whether the presence of mitoses in hyperchromatic crowded groups (HCGs) in cervical cytological specimens can serve as cytological criteria for high-grade squamous intra-epithelial lesions (HSILs).

Methods and Material

Various parameters were examined, including the frequency of mitotic figures per high power field (HPF) in Pap, hematoxylin eosin (HE) samples, and PHH3 immunocytochemical (ICC) and immunohistochemical (IHC) analyses.

Results

In the Pap and PHH3-ICC samples, the number of mitotic figures observed in HCGs was significantly higher in HSIL (P < 0.001) compared to other groups. Furthermore, the frequency of observing two or more mitoses was significantly higher in HSIL (Pap: P = 0.002, PHH3-ICC: P < 0.001) than in low-grade squamous intra-epithelial lesions (LSILs). Moreover, a comparison between Pap samples and PHH3-ICC showed that the frequency of two or more mitoses was significantly higher in the PHH3-ICC analysis of HSIL (P = 0.042). Regarding HE and PHH3-IHC samples, counting the number of mitoses in the lower and middle/upper layers of the squamous epithelial layer revealed that HSIL had a significantly higher value (HE: P = 0.0089, PHH3-IHC: P = 0.0002) than LSIL in the middle/upper layers.

Conclusions

Hence, the presence of two or more mitotic figures in HCGs per HPF in cervical cytology indicates a suspicion of HSIL. The detection of mitoses in PHH3-ICC samples is more sensitive and easier to observe than in Pap samples, making it a valuable mitotic marker.

Effects of Menstrual Cycle on Various Morphologies of High-Grade Squamous Intraepithelial Lesions in SurePath™ Liquid-Based Cervical Cytology

INTRODUCTION

The morphology of high-grade squamous intraepithelial lesion (HSIL) on Papanicolaou (Pap) smears widely varied, including syncytial aggregates, sheets, and scattered single cells, and no particular cellular pattern is consistently observed. Therefore, this study aimed to determine whether the menstrual cycle affects the cellular pattern of HSILs, an effort to avoid false negatives due to the oversight of scattered small single HSIL cells in the cytological triage of human papillomavirus-positive women.

METHODS

A total of 147 HSIL samples of liquid-based cytology (LBC) in patients with cervical intraepithelial neoplasia grade 2 or 3 were obtained, and then, the relationship between cellular patterns, such as single-cell-like and syncytial aggregates, and menstrual cycles classified into six phases was analyzed. If a syncytial aggregate was present, the number of cells constituting the aggregate was visually counted under the microscope.

RESULTS

HSILs in scattered single cells and small sheets of <6 on LBC samples accounted for 43% (23/54) during the late proliferative phase of the menstrual cycle. A moderately strong statistically significant association was observed between cellular patterns and menstrual cycles (χ2 [3] = 9.423, p < 0.05) (Cramer's V = 0.253). The value of adjusted residuals showed a statistically significant increased proportion of single-cell-like patterns during the late proliferative phase (p < 0.01).

CONCLUSIONS

The present study demonstrated that HSIL cells in Pap smears in the late proliferation phase have a high frequency of single-cell-like patterns. In human papillomavirus-positive Pap smears with a clean background and predominantly superficial cells, careful microscopic observation by targeting single HSIL cells can potentially reduce false negatives.

Atypical glandular cells (AGC): Cytology of glandular lesions of the uterine cervix

The Pap smear is a well-known screening tool for squamous lesions of the uterine cervix. However, its screening role in glandular lesions is less effective. The incidence of squamous cell carcinoma of the cervix has dramatically decreased with the advent of Pap smear and recent understanding related to HPV carcinogenesis of cervical cancers including the advent of HPV vaccines. However, in recent years, the incidence of glandular abnormalities, diagnosed on Pap smears, has increased with greater sensitivity and precision. The incidence of atypical glandular cells (AGC) is approximately 0.18-0.74% of all cervical smears with a reported prevalence of 2.5% among all Pap smears. A high degree of suspicion, good clinical history, and the presence of diagnostic cytomorphological findings are essential for the proper interpretation of glandular cell abnormalities. A methodical approach to evaluate Pap smear greatly helps interpretation and avoids the diagnostic pitfalls. The Bethesda System for reporting cervical cytology has categorized glandular cell abnormalities into various categories as follows: Endocervical adenocarcinoma in situ (AIS)Atypical glandular cells (AGCs) Endocervical cells: a1 NOS or specify in comments; a2 Favor neoplasticEndometrial cells: NOS or specify in comments Adenocarcinoma (AdCa) EndocervicalEndometrialExtrauterineNOS Subtle differences in quantitative and qualitative cytologic features are essential for distinguishing one category from another. In this chapter, we highlight an organized approach for the interpretation of glandular abnormalities in Pap smear for our readers. This is an overview of the Bethesda categories, the reason for classification, and differential diagnosis with key characteristic features. An approach to the methodical evaluation of hyperchromatic crowded groups is discussed with key cytomorphologic differences. An algorithmic approach is suggested to facilitate the interpretation of various AGC categories.

The association of atypical squamous cells, cannot exclude a high grade squamous intraepithelial lesion, hyperchromatic crowded groups and high grade squamous intraepithelial lesions involving endocervical glands

BACKGROUND

Hyperchromatic crowded groups (HCGs) are often classified as atypical squamous cells, cannot exclude a high grade squamous intraepithelial lesion (ASC-H) on ThinPrep Pap tests. This study reports on the association of HCG's with high grade squamous intraepithelial lesions (HSIL) involving endocervical glands.

METHODS

Over a 3-year period (January 1, 2018-December 31, 2020), 115 (0.2%) of 63,817 Pap tests were diagnosed as ASC-H. Histologic follow-up was available in 76 (66%) cases; 42 (55%) cervical biopsies; and 34 (45%) cervical cones/LEEPs.

RESULTS

Based on the histologic results, 49 ASC-H cases showed HSIL/CIN 3 and form the basis of this study. ThinPrep Pap tests showed two cell patterns; atypical immature squamous metaplastic cells and HCGs, each of which was difficult to distinguish from HSIL. On histologic correlation all 10 ASC-H Pap Tests with individual atypical immature squamous metaplastic cells showed HSIL/CIN 3 without endocervical gland involvement and 37 (95%) of the 39 Pap Tests with HCGs showed HSIL/CIN 3 with endocervical gland involvement.

CONCLUSION

The results of this study support the premise that a subset of HCGs represent endocervical gland involvement by HSIL as opposed to a glandular lesion; in particular endocervical adenocarcinoma in-situ.

Architectural aspects of cell-blocks as small biopsies

Cell-block preparations have become an essential part of integrated cytology diagnosis. They are essentially microbiopsies that are formalin fixed and embedded in paraffin. This has become more prevalent with greater sample procurement due to the advent of newer biopsy techniques and needles. Cell-blocks allow retrieval of small tissue fragments from cytology specimens that sometimes cannot be processed by alternate cytologic techniques. They represent concentrated, cell-enriched preparations that provide cytologists with the opportunity to evaluate cellular architecture, as well as to perform ancillary testing. A cell-block compatible sample may thus obviate the need for a more invasive procedure such as a tissue biopsy. Microscopic examination of cell-blocks is quick, avoids obscuring material, permits cells to be evaluated in one focal plane, and allows the histologic architecture such as glandular differentiation, papillary formations, and sometimes invasion to be easily identified. This new era of “cytohistology” accordingly requires practicing cytologists to become more familiar with histopathology. This review article discusses the benefit of various architectural patterns identifiable in cell-blocks employed as an adjunct to Pap tests, exfoliative fluid specimens, and fine-needle aspirations.

Pattern of cervical biopsy results in cases with cervical cytology interpreted as higher than low grade in the background with atrophic cellular changes

Objective:

The cytomorphological changes associated with atrophic cellular pattern (ACP) in cervical cytology smears may mimic high-grade squamous intraepithelial lesion (HSIL). Due to this, there may be higher chances of cytomorphological overinterpretation in cases with ACP. Estrogen therapy (ET) (topical or systemic) would reverse the changes related to atrophy and repeat Pap smear after ET should correct the false positives. This approach would minimize the unindicated invasive interventions. However, performing immediate biopsies following “higher than low-grade squamous intraepithelial lesion (LSIL) (atypical squamous cells-cannot exclude HSIL, low-grade squamous intraepithelial lesions-cannot exclude HSIL, and HSIL) interpretations” in such cases, is a general trend. Pap smears with “higher than LSIL interpretations” in association with ACP over a period of 10 years were selected.

Materials and Methods:

A total of 657,871 cases over 10 years were reviewed, of which 188 Pap smears interpreted as higher than LSIL interpretations with ACP were selected randomly for this study.

Result:

Of these 188 cases, 67 underwent biopsies which were reviewed and compared with 67 biopsies performed for “higher than LSIL interpretation” cases without ACP. The follow-up biopsy material was reviewed including elective p16 immunohistochemistry with other clinical details including high-risk HPV test results as indicated.

Conclusion:

The findings demonstrated that Pap smears with ACP have higher false positives due to tendency for cytomorphologic overinterpretation as compared to non-ACP group.

Cytomorphological Features of Hyperchromatic Crowded Groups in Liquid-Based Cervicovaginal Cytology: A Single Institutional Experience

BACKGROUND

Hyperchromatic crowed groups (HCGs) are defined as three-dimensional aggregates of crowded cells with hyperchromatic nuclei, and are frequently encountered in cervicovaginal liquid-based cytology (LBC). Here, we aimed to examine the prevalence of HCGs in cervicovaginal LBC and the cytomorphological characteristics of various epithelial cell clusters presenting as HCGs.

METHODS

We first examined the prevalence of HCGs in a "routine cohort" of LBC cytology (n=331), consisting of all cervicovaginal LBCs accessioned over 3 days from outpatient clinics (n=179) and the screening population (n=152). Then we examined a second "high-grade epithelial cell abnormalities (H-ECA) cohort" (n=69) of LBCs diagnosed as high-grade squamous intraepithelial lesion (HSIL), squamous cell carcinoma (SCC), or adenocarcinoma during 1 year.

RESULTS

HCGs was observed in 34.4% of the routine cohort and were significantly more frequent in the epithelial cell abnormality category compared to the non-neoplastic category (p=.003). The majority of HCGs represented atrophy (70%). Of the 69 histologically confirmed H-ECA cases, all contained HCGs. The majority of cases were HSIL (62%), followed by SCC (16%). Individually scattered neoplastic cells outside the HCGs were significantly more frequent in SCCs compared to glandular neoplasia (p=.002). Despite the obscuring thick nature of the HCGs, examining the edges and the different focal planes of the HCGs and the background were helpful in defining the nature of the HCGs.

CONCLUSIONS

HCGs were frequently observed in cervicovaginal LBC and were mostly non-neoplastic; however, neoplastic HCGs were mostly high-grade lesions. Being aware of the cytomorphological features of different HCGs is important in order to avoid potential false-negative cytology interpretation.

A Comparison of Cytomorphological Features of ASC-H Cells Based on Histopathological Results Obtained from a Colposcopic Target Biopsy Immediately after Pap smear Sampling

Background: To compare the cytomorphological features of atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H) observed in a liquid-based Pap smear with the histopathological features observed in a concurrent colposcopic biopsy specimen obtained immediately after obtaining the Pap smear. Methods: Cytomorphological features such as cytoplasmic differentiation, nuclear/cytoplasm (N/C) ratio, chromatin pattern, thickening of nuclear contour, and the appearance of the nucleolus of 247 ASC-H obtained from 25 liquid-based Pap smear ASC-H cases were compared with those of the cells obtained from biopsied samples. Human papillomavirus (HPV) infection was tested for 39 HPV genotypes using Uniplex E6/E7 polymerase chain reaction method. Results: Of the 25 ASC-H cases, 22 (88%) showed cervical intraepithelial neoplasia grade 1 or greater (CIN1+) and 3 (12%) were benign. HPV infection was detected in 100% CIN1+ cases and 66.7% benign cases. Significant differences such as marked hyperchromasia, thickened nuclear contour, and prominent nucleoli were observed between ASC-H cases with CIN1+ and the benign cases. Conclusion: The presence of small dysplastic cells displaying marked hyperchromasia, thickening of nuclear contour, and prominent nucleoli on Pap smear strongly suggest the presence of CIN in ASC-H cases.

The reporting rates of atypical glandular cells and their HPV testing and histologic follow-up results: a comparison between ThinPrep and SurePath preparations from a single academic institution

INTRODUCTION

The interpretation of atypical glandular cells (AGCs) remains a major challenge in gynecologic cytopathology using liquid-based cytology (LBC) (ThinPrep and SurePath). The comparison of performance of detecting glandular abnormalities using these 2 methods is lacking. We investigated the reporting rates of AGCs, human papillomavirus (HPV) testing, and histologic follow-up results in ThinPrep (TP) and SurePath (SP) samples.

MATERIALS AND METHODS

In our institution, both TP and SP were utilized during the period between January 2014 and June 2017. A retrospective search was conducted to identify patients with AGCs from 58,591 LBCs (27,041 TP and 31,550 SP). Roche (Pleasanton, CA) cobas HPV testing and histologic follow-up results were collected.

RESULTS

The reporting rates of AGCs for TP (0.7%) or SP (0.2%) were within the College of American Pathologists benchmark ranges, but the reporting for TP was significantly greater than that for SP (P < 0.0001). The HPV-positive rates were 26.0% and 19.4% in TP-AGCs and SP-AGCs, respectively, with no statistical significance. A total of 137 (74.9%) TP-AGCs and 54 (74%) SP-AGCs had histologic follow-up. High-grade squamous intraepithelial lesions (HSIL)/squamous cell carcinoma were identified in 8.8% (12 of 137) of TP-AGCs and 13% (7 of 54) of SP-AGCs. Adenocarcinomas including endocervical and endometrial adenocarcinomas were identified in 9.5% (13 of 137) of TP-AGCs and 13% (7 of 54) of SP-AGCs. Together, 18.2% (25 of 137) of TP-AGCs and 25.9% (14 of 54) of SP-AGCs showed either HSIL or carcinoma in histologic follow-up, but with no statistical significance.

CONCLUSIONS

TP preparation detected considerably more AGCs than SP preparation. There was no statistical significant difference in HPV-positive rates or histologic follow-up outcomes between TP-detected AGCs and SP-detected AGCs.

Atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion: diagnostic features in surepath™ cervical samples

This study was undertaken to identify the situations in which a diagnosis of "Atypical squamous cells, cannot exclude a high-grade squamous intraepithelial lesion (ASC-H)" is offered in SurePath™ cervical samples and to identify cytological criteria helpful in predicting high-grade disease. 2,335 (3.4%) SurePath samples reported as atypical squamous cells (ASC) over a period of 2 years, including 1,112 cases with known hrHPV status were retrieved. 105/1,112 cases were categorized into ASC-H, and slides were available for review in 88/105 cases. These 88 samples were divided into two categories based on follow-up histological outcome and hrHPV status-category A: cases with CIN2+ lesions on follow-up (n = 48) and category B: cases with ≤CIN1 lesions or hrHPV negative status (n = 40). 78% (82/105) cases of ASC-H tested positive for hrHPV. Overall CIN2+ lesions were found in 50.3% (53/105) cases. Of 88 cases reviewed, HCGs were noted in 56.3% (27/48) cases in category A and 75% (30/40) cases in category B. Dispersed metaplastic cells and scattered small atypical cells were seen in 37.5% (18/48) cases in category A and 12.5%(5/40) in category B. The majority of cases with dispersed atypical cells had <20 cells/sample and cases with HCGs had <10 HCGs per sample. The majority of the cases reported as ASC-H contained HCGs. Of these groups with nuclear crowding, disorganization and those with steep edges ("blocks") are likely to predict high-grade disease. The samples with only dispersed atypical cells had <20 cells/sample in majority of cases. In these, a disproportionate and especially high nuclear: cytoplasmic ratio and irregular chromatin were the most useful features in predicting high-grade disease.

Gynecologic cytology on conventional and liquid-based preparations: a comprehensive review of similarities and differences

Liquid-based preparations (LBPs) have largely replaced conventional Papanicolaou smears (CPS) for cervical samples in the United States and in many other industrialized countries. The two FDA-approved LBP currently in use include ThinPrep (TP), (Hologic Inc., Bedford, MA) and SurePath (SP), (BD Diagnostic, Burlington, NC). Split-sample and direct-to-vial studies have shown that LBPs show an overall improvement in sample collection and processing, reduce artifacts that interfere in diagnosis, are more sensitive, can be utilized for ancillary tests and are a cost-effective replacement for CPS. Comparative analyses of diagnostic accuracy indicate that LBPs perform at least as well as CPS. However, the added advantages of standardized, automated preparations and screening, reduced unsatisfactory rate, improved specimen adequacy and ability to perform human papillomavirus (HPV) test, are enough to continue use of LBP. The cytologic features in LBP are similar to CPS with subtle differences, particularly in background information. There are also subtle differences between the two LBPs, SP and TP, which are reflective of different sampling devices, collection media, and processing techniques. Architecturally, LBP shows smaller cell clusters and sheets and more dyscohesion. Cytologically, enhanced nuclear features and smaller cell size are more prominent. Advances in liquid-based Papanicolaou's (Pap) test have lead to well-defined patient management guidelines by the American Society for Colposcopy and Cervical Pathology. Herein, we review these aspects of Pap test including, morphology, automation, ancillary tests (HPV and immunochemistry), pertinent QA/QC monitors, patient management guidelines, and review of pertinent literature.

Should LSIL with ASC-H (LSIL-H) in cervical smears be an independent category? A study on SurePath specimens with review of literature

Background

Cervical smears exhibiting unequivocal features of 'low grade squamous intraepithelial lesion' (LSIL) are occasionally also admixed with some cells suspicious for, but not diagnostic of, 'high grade squamous intraepithelial lesion' (HSIL). Only a few studies, mostly reported as abstracts, have evaluated this concurrence. In this study, we evaluate the current evidence that favors a distinct category for "LSIL, cannot exclude HSIL" (LSIL-H), and suggest a management algorithm based on combinations of current ASCCP guidelines for related interpretations.

Methods

We studied SurePath™ preparations of cervical specimens from various institutions during one year period. Cytohisto correlation was performed in cases with cervical biopsies submitted to our institution. The status of HPV DNA testing was also noted in some LSIL-H cases with biopsy results.

Results

Out of 77,979 cases 1,970 interpreted as LSIL (1,523), LSIL-H (146), 'atypical squamous cells, cannot exclude HSIL' (ASC-H) (109), and HSIL (192) were selected. Concurrent biopsy results were available in 40% (Total 792 cases: 557 LSIL, 88 LSIL-H, 38 ASCH, and 109 HSIL). Biopsy results were grouped into A. negative for dysplasia (ND), B. low grade (HPV, CIN1, CIN1 with HPV), and C. high grade (CIN 2 and above).

The positive predictive values for various biopsy results in relation to initial cytopathologic interpretation were: a. LSIL: (557 cases): ND 32% (179), low grade- 58% (323), high grade- 10% (55); b. LSIL-H: (88 cases): ND 24% (21), low grade- 43% (38), high grade- 33% (29); c. ASCH: (38 cases): ND 32% (12), low grade- 37% (14), high grade- 31% (12); d. HSIL (109 cases): ND 5% (6), low grade 26% (28), high grade 69% (75). The patterns of cervical biopsy results in cases reported as LSIL-H were compared with that observed in cases with LSIL, ASC-H, and HSIL.

94% (32 of 34) of LSIL-H were positive for high risk (HR) HPV, 1 was negative for HR HPV but positive for low risk (LR), and 1 LSIL-H was negative for HR and LR both.

Conclusion

LSIL-H overlapped with LSIL and ASC-H, but was distinct from HSIL. A management algorithm comparable to ASC-H and HSIL appears to be appropriate in LSIL-H cases.