Hyperchromatic Crowded Groups Research Articles

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

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). 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. 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. 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.

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.

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. 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. 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. 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.

Role of fractal dimension in distinguishing benign from malignant endometrial clusters in liquid-based cervical samples.

Exfoliated endometrial cells are often seen as hyperchromatic crowded groups (HCGs) in cervical samples. It is challenging for the cytopathologists to discriminate between HCGs of benign and malignant endometrial cells. Fractal dimension (FD) analysis has proved to be a useful tool in discriminating between different types of cell groups in previous studies. This study was conducted to evaluate the utility of FD for differentiating between benign and malignant endometrial HCGs, in liquid-based cervical samples. Two groups of cervical samples, with subsequent histopathology, were selected: Group A: 30 cases with benign endometrial HCGs; and Group B: 39 cases with malignant endometrial HCGs. Image J, NIH and FracLac software were used for selecting and measuring the FD of the HCGs. Student t-test was used for statistical analysis. The mean FD for benign endometrial HCGs (1.066943±0.0699) was significantly lower than that of the malignant endometrial HCGs (1.086271±0.05121; P=.001). Using receiver operator characteristic curve analysis, we determined that an FD cut-off value of 1.01 would yield sensitivity of 90.3%, specificity of 26.1%, positive predictive value of 47.3% and negative predictive value of 78.6%. The measurement of FD of HCGs in cervical samples can serve as a useful screening adjunct to differentiate malignant from benign HCGs, owing to its high sensitivity. However, in view of its low specificity and positive predictive value, we recommend that cases labelled as malignant by the FD value be confirmed for malignancy by other methods.

Cervical high-grade squamous intraepithelial lesion on conventional cytology: Cytological patterns, pitfalls, and diagnostic clues.

Conventional cervical cytology, which has a relatively low sensitivity in diagnosing high-grade lesions as compared to liquid-based cytology, is still being practiced in low resource settings. This study aimed at elucidating various cytomorphological patterns, pitfalls, and subtle clues to high-grade squamous intraepithelial lesion (HSIL) diagnosis on conventional cervical cytology through cytologic-histologic correlation. Cervical biopsies reported as CIN2/3 were correlated with their corresponding Pap smears over a 10-year period to determine the frequency of undercalls. For characterization of overcalls, cervical smears reported as HSIL and their corresponding biopsies during the same period were correlated. The discordant cases in both the groups were reviewed for problematic patterns and pitfalls in cytological diagnosis of HSIL. Of the 142 biopsies with CIN2/3, 29 (20.4%) cases had been undercalled on cytology. Sixteen (16) of these could be reclassified as ASC-H/HSIL on smear review. Smears showing predominant cells of low-grade squamous intraepithelial lesion grade with a few HSIL cells and those with small abnormal cells in an atrophic background formed the main confounders for HSIL underdiagnosis. Thirteen (13) out of 130 (10%) Pap smears called as HSIL, where biopsy diagnosis was less than CIN2, were labeled as overcalls. Atypical metaplasia, hyperchromatic crowded groups, and reparative changes constituted the major diagnostic pitfalls on cytology. A diligent smear review helped to reduce the undercall and overcall rates to 9.1% and 2.3%, respectively. Awareness of morphological challenges in interpretation of HSIL among cytopathologists practicing cervical cytology would assist in reducing the diagnostic errors and ensure better patient management.

BD シュアパス&lt;sup&gt;TM&lt;/sup&gt;法で高度扁平上皮内病変と評価した 250 例の hyperchromatic crowded cell groups の出現頻度と細胞診断上の意義

BD シュアパス&lt;sup&gt;TM&lt;/sup&gt;法で高度扁平上皮内病変と評価した 250 例の hyperchromatic crowded cell groups の出現頻度と細胞診断上の意義

What is new in the evaluation of diagnostic digital cytopathology in cervicovaginal smears?

The successful integration of digital cytopathology into daily practice presents unique challenges. Whole slide imaging (WSI) of cytologic specimens must provide high resolution images on small cellular areas. Fine focus at high magnification is important for evaluation of three dimensional objects such as hyperchromatic crowded groups in cervicovaginal cytology.[1] The introduction of z-axis focusing in which multiple planes in the z-axis are scanned and incorporated in the final image called a “z-stack” allows for the fine focus functionality required in the subspecialized field of cytopathology.[2] The evaluation of diagnostic digital cytopathology in liquid-based cervicovaginal smears has been limited. A recent study by Wright et al., at Weill Cornell Medical College of Cornell University in Houston, Texas attempted to discover the advantages and limitations of WSI in this area.[3] Seven participants (3 pathologists and 4 cytotechnologists) examined 11 cervicovaginal papanicolaou smears (Thin-Prep and SurePath) which were scanned at ×20, ×40 and ×40 z-stack digital magnifications using the BioImagene iScan Coreo Au 3.0 scanner. The digital images were viewed on a computer equipped with an Intel Pentium 3.44-GHz processor, 1 GB RAM, 64 MB VRAM and a display monitor with 1600 × 1024 pixel resolution. The diagnosis and time to reach a diagnosis were recorded. The results were compared with manually reading the same glass slides. The results showed that accuracy of interpretation and the time to reach a diagnosis was superior with glass slides as compared with all of the digital magnifications. When the different digital magnifications were compared, ×40 and ×40 with z-stack had better accuracy and a shorter time to diagnosis than the ×20 magnification. The authors noted that the ×40 z stack imaging performed better in the diagnosis of endometrial adenocarcinoma and commented on the usefulness of WSI cytology in archiving for storage and future comparison, especially if the specimen was used entirely for ancillary testing. However, due to the diagnostic and technologic difficulties presented by WSI, the authors concluded that WSI in cervicovaginal cytology is not ready for daily screening and diagnosis. This finding is somewhat discouraging considering liquid-based specimens have a smaller cellular area to scan, screen and diagnose, which was anticipated as a promising area of early adoption of digitalization.

PAX8 and PAX2 Expression in Endocervical Adenocarcinoma In Situ and High-Grade Squamous Dysplasia

Transcription factors PAX2 and PAX8 are expressed in the nuclei of Müllerian glandular epithelial cells. In situ carcinomas of the cervix are exemplified by adenocarcinoma in situ (AIS) and high-grade squamous intraepithelial lesions (HSILs), both of which present histologically as hyperchromatic crowded groups of epithelial cells exhibiting loss of polarity. Herein, we sought to investigate the immunohistochemical expression of PAX8 and PAX2 in AIS and HSIL. A total of 66 and 55 cases of AIS and HSIL were examined, respectively. PAX8 positivity was observed in 64 (97%) of 66 cases of AIS. Nuclear PAX2 expression was completely lost in 59 (89%) of the 66 cases of AIS. Eleven (20%) of the 55 HSILs were positive for PAX8. The difference in PAX8 positivity rates between AIS and HSIL was statistically significant (P<0.0001). The PAX2 immunostain was completely negative in the 18 HSILs examined for PAX2 expression. PAX8 and PAX2 immunostaining patterns in benign endocervical glandular epithelium were examined for 98 and 62 cases, respectively. The benign endocervical glandular epithelium was positive for PAX8 and PAX2 expression in 100% and 97% of cases, respectively. In conclusion, immunohistochemical analysis for PAX2 is effective in discriminating AIS from benign endocervical glandular epithelium. The majority of AIS lesions and a subset of HSILs are PAX8(+). With regard to the distinction between AIS and HSIL, a PAX8(-) immunophenotype is particularly predictive of high-grade squamous dysplasia.

Optimal z-axis scanning parameters for gynecologic cytology specimens

Background: The use of virtual microscopy (VM) in clinical cytology has been limited due to the inability to focus through three dimensional (3D) cell clusters with a single focal plane (2D images). Limited information exists regarding the optimal scanning parameters for 3D scanning. Aims: The purpose of this study was to determine the optimal number of the focal plane levels and the optimal scanning interval to digitize gynecological (GYN) specimens prepared on SurePath™ glass slides while maintaining a manageable file size. Subjects and Methods: The iScanCoreo Au scanner (Ventana, AZ, USA) was used to digitize 192 SurePath™ glass slides at three focal plane levels at 1 µ interval. The digitized virtual images (VI) were annotated using Biolmagene’s Image Viewer. Five participants interpreted the VI and recorded the focal plane level at which they felt confident and later interpreted the corresponding glass slide specimens using light microscopy (LM). The participants completed a survey about their experiences. Inter-rater agreement and concordance between the VI and the glass slide specimens were evaluated. Results: This study determined an overall high intra-rater diagnostic concordance between glass and VI (89-97%), however, the inter-rater agreement for all cases was higher for LM (94%) compared with VM (82%). Survey results indicate participants found low grade dysplasia and koilocytes easy to diagnose using three focal plane levels, the image enhancement tool was useful and focusing through the cells helped with interpretation; however, the participants found VI with hyperchromatic crowded groups challenging to interpret. Participants reported they prefer using LM over VM. This study supports using three focal plane levels and 1 µ interval to expand the use of VM in GYN cytology. Conclusion: Future improvements in technology and appropriate training should make this format a more preferable and practical option in clinical cytology.

P16INK4a and ProEx C Immunostains Facilitate Differential Diagnosis of Hyperchromatic Crowded Groups in Liquid-Based Papanicolaou Tests with Menstrual Contamination

Objective: Evaluation of hyperchromatic crowded groups in Papanicolaou (Pap) tests from women during menstruation can be a diagnostic pitfall due to similar morphological appearances with significant cervical lesions. We studied the results of p16^INK4a and ProEx C on cell blocks from Pap tests during menstruation in an attempt to facilitate the differentiation. Study Design: Immunohistochemical stains for p16^INK4a and ProEx C were performed on 25 cell blocks prepared from residual liquid-based cervical material with menstrual contamination. Results: Strong, diffuse, and full thickness staining pattern for p16^INK4a and ProEx C was observed in cases of high-grade squamous intraepithelial lesion (HSIL) and small cell carcinoma of the cervix. The low-grade squamous intraepithelial lesion cases and cases negative for intraepithelial lesion or malignancy were negative for ProEx C, with focal staining for p16^INK4a. The benign endometrial cells had either negative or focal patchy staining, which is often associated with tubal metaplasia. Conclusion: p16^INK4a and ProEx C are sensitive markers for identifying significant lesions in Pap test specimens with menstrual contamination. Patchy/mosaic staining may be seen in benign endometrial tissue with tubal metaplasia, but strong, diffuse staining likely indicates HSIL or carcinoma. These findings can be helpful in interpreting hyperchromatic crowded groups in menstrual Pap specimens. Further study may be prudent, being aware of the small study group.

Ancillary testing in liquid based cytology to distinguish cervical glandular neoplasia from tuboendometrial metaplasia in a young woman

A 33-year old woman had a cervical sample taken at colposcopy clinic. Seven years prior to this, at the age of 26, she had had a cytological diagnosis of cervical glandular neoplasia (cytology descriptor indicated cells suspicious of endocervical neoplasia) and severe dyskaryosis. Confirmation and treatment were by LLETZ and knife cone, and, in keeping with England and Wales National Health Service guidelines, this woman was under follow-up by the colposcopy clinic. Intervening cytological follow-up included a number of negative cytological samples interspaced with one equivocal report. A recent repeat cytology which was rather cellular contained several hyperchromatic crowded cell groups (HCCG's). Careful examination revealed benign endometrial clusters, LUS, TEM and endocervical cells in strips showing pseudostratification and loss of polarity. Following an agar block, there was positive staining for p16 and Ki-67 in the abnormal groups whilst the benign TEM cells stained positive for bcl-2.

Synchronous high‐grade squamous intraepithelial lesion and adenocarcinoma in situ of cervix in a young woman presenting with hyperchromatic crowded groups in the cervical cytology specimen: Report of a case

We report a 29-year-old woman who underwent routine gynecologic evaluation at a community clinic and had a cervical sample drawn for liquid-based cytologic evaluation. At cytology, many hyperchromatic crowded groups (HCG) were present, but a consensus could not be established whether the abnormal cells were primarily glandular or squamous with secondary endocervical glandular involvement. An interpretation of atypical endocervical cells, favor neoplastic, was rendered and biopsy advised if clinically appropriate. At biopsy, the cervix contained synchronous squamous cell carcinoma in situ, secondarily involving endocervical glands, and neighboring adenocarcinoma in situ. Immunohistochemistry for Ki-67 and p16(INK4A) crisply and precisely stained both the lesions, clearly separating them from the adjacent uninvolved mucosa. This case re-emphasizes the challenge associated with accurate evaluation of HCG at cytology, the significance of ancillary testing for surrogate markers of high-risk HPV (HR-HPV) infection, the need for adjunct testing for HPV-DNA in the setting of HCG at cervical cytology, and a recommendation to set up studies to evaluate the role of surrogate markers of HR-HPV infection in cytologic samples with HCG.

Error reduction and risk management in cytopathology

Currently, tort reform is not a major priority in either the Congress of the United States or in state legislatures. Thus, it is fortunate that medical negligence claims against pathologists are relatively infrequent, at 8.3% per year per 100 insured pathologists (data from the Doctors' Company, 2000-2003). However, claims for "missed" cervical cytology specimens rank third, behind those for alleged misinterpretation of breast biopsies and pigmented skin lesions. The severity of cervical cytology errors is high, at almost $700,000 per claim, surpassed only by those concerning melanoma. There are common threads that appear consistently in the analysis of slides from allegedly misdiagnosed cervical cytology cases, including small-cell variants of high-grade squamous intraepithelial neoplasia (HGSIL), present in small numbers; hyperchromatic crowded cell groups; atypical squamous cells of undetermined significance (ASCUS); smears taken during menses; other bloody smears, particularly with degenerative features or excessive inflammation; others showing atypical repair; and unsatisfactory samples. It is important for pathologists to spend time with cytotechnologists to emphasize the patterns of abnormal smears at low microscopic magnification and those backgrounds featuring blood and inflammation which require particular attention. Managing the "look-back" requirement of the Clinical Laboratory Amendments of 1988 (CLIA88) is also crucial; the need to issue amended reports as a consequence of that provision is quite rare. Procedures for administrating and reporting retrospective reviews under the CLIA88 should be clearly outlined in a peer-reviewed procedure document in each laboratory. They should be reviewed and approved by risk managers or insurance carriers, and documented in such a manner that one obtains maximal protection from legal discovery. Consumer education is particularly important in maintaining laboratory performance and reducing risk from error in cytology. Periodic feedback to clinicians on the quality of their smear preparations, the use of ancillary techniques (eg, human papillomavirus testing), and discussion of reporting terminology are important. Moreover, one should stress the need for pertinent clinical history that is often required to initiate quality control measures for evaluation and reporting of cervical cytology specimens. The incidence of cervical cancer in the United States, at only 9700 new cases per year, is low, emphasizing the need for clinical vigilance, attention to unexplained symptoms and signs, and biopsies of any cervical abnormality. These and other efforts may assist in reducing the risk of litigation attached to allegedly false-negative gynecologic and nongynecologic cytology samples.

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

ObjectiveHyperchromatic crowded groups (HCG), a term first introduced into the cytology literature by DeMay in 1995, are commonly observed in Pap tests and may rarely be associated with serious but difficult to interpret lesions. In this study, we specifically defined HCG as dark crowded cell groups with more than 15 cells which can be identified at 10× screening magnification.MethodsWe evaluated consecutive liquid-based (Surepath) Pap tests from 601 women (age 17–74 years, mean age 29.4 yrs) and observed HCG in 477 cases. In all 477 HCG cases, Pap tests were found to be satisfactory and to contain an endocervical sample. HCG were easily detectible at 10× screening magnification (size up to 400 um, mean 239.5 um) and ranged from 1 to 50 (mean 19.5) per Pap slide.ResultsHCG predominantly represented 3-Dimensional groups of endocervical cells with some nuclear overlap (379/477 – 79%), reactive endocervical cells with relatively prominent nucleoli and some nuclear crowding (29/477 – 6%), clusters of inflammatory cells (25/477 – 5.2%), parabasal cells (22/477 – 4.6%), endometrial cells (1/477 – 0.2%). Epithelial cell abnormalities (ECA) were present in only 21 of 477 cases (4.6%). 18 of 21 women with HCG-associated ECA were less than 40 years old; only 3 were =/> 40 years. HCG-associated final abnormal Pap test interpretations were as follows: ASCUS (6/21 – 28%), LSIL (12/21 – 57%), ASC-H (2/21 – 9.5%), and HSIL/CIN2-3 (3/21 – 14%). The association of HCG with ECA was statistically significant (p = 0.0174. chi-square test). In patients with ECA, biopsy results were available in 10 cases, and 4 cases of biopsy-proven CIN2/3 were detected. Among these four cases, HCG in the Pap tests, in retrospect represented the lesional high grade cells in three cases (one HSIL case and two ASC-H cases). Interestingly, none of the 124 cases without HCG were found to have an epithelial cell abnormality.ConclusionWe conclude: a. HCG are observed in a high proportion of cervical smears. b. In the vast majority of cases, HCG are benign. c. ECA were only observed in cases with HCG. This observation is consistent with the hypothesis that the presence of HCG in Pap tests most often represents adequate sampling of the transformation zone, thus increasing the chances of detecting an epithelial cell abnormality. d. Only a few cases with HCG were associated with a serious ECA, but careful scrutiny of all HCG appears warranted to avoid the potential diagnostic pitfall of a significant false negative interpretation.

Pleomorphic spindle cells and hyperchromatic crowded groups in a cervical smear

Pleomorphic spindle cells and hyperchromatic crowded groups in a cervical smear

Hyperchromatic Crowded Groups in Cervical Cytology—Differing Appearances and Interpretations in Conventional and ThinPrep Preparations: A Study From the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology

The practice of gynecologic cytology requires that high-grade squamous intraepithelial lesion (HSIL) be precisely recognized. In this regard, hyperchromatic crowded groups are known to be difficult to classify in conventional gynecologic cytology, but whether this is true in ThinPrep specimens is uncertain. To assess whether hyperchromatic crowded groups of cells in challenging HSIL cases are a problem in ThinPrep preparations, and whether these groups differ in appearance from those of conventional smears. Sixteen images were taken from both conventional smears and ThinPrep slides that had a reference diagnosis of HSIL in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, but had performed poorly on subsequent participants' reviews. These 32 representative images were of hyperchromatic crowded groups and were classified by 20 Cytopathology Resource Committee members (17 pathologists and 3 cytotechnologists), who were masked to the reference diagnosis. A consensus classification was derived using the majority opinion of the individual reviewers. Finally, 5 cytologic features were assessed for those images that were interpreted as abnormal by the consensus classification. None of the 32 images was uniformly interpreted as either benign, squamous lesion, or glandular lesion on individual review. Only 27% of individual interpretations of conventional smear images and 15% of ThinPrep images were interpreted as HSIL/squamous cell carcinoma (P < .001). Individual interpretations of ThinPrep images as glandular lesions (60%) were more often made than those of conventional smears (44%, P < .001). The consensus interpretation of ThinPrep images was glandular lesion in 75% of cases, whereas fewer than 50% of the consensus interpretations of conventional smear images were in this category. Conventional smear images were characterized by elongate nuclei (43%) and large nuclei (71%), whereas ThinPrep images more often showed rounded smooth edges (53%) and small nuclei (80%), and were recognized as a glandular lesion. Hyperchromatic crowded groups of cells are a source of difficulty in challenging HSIL cases for both conventional smears and ThinPrep specimens. In conventional smears, these groups are more likely to be labeled as a squamous lesion, owing to their elongate and large nuclei. In ThinPrep specimens, however, these groups are more likely to be labeled as glandular lesions, owing to their smooth contoured borders and small nuclei.

Hyperchromatic Crowded Groups

A problem in the diagnosis of Papanicolaou smears--the interpretation of "hyperchromatic crowded groups" (HCGs)--is identified and analyzed. HCGs usually represent benign entities such as endometrial cells, syncytial aggregates in severe atrophy, or fragments of endocervical tissue, the latter being seen with increasing frequency due to the use of the endocervical brush. Tubal metaplasia is another common, benign source of HCGs. However, occasionally HCGs represent serious lesions, such as carcinoma in situ, invasive squamous cell carcinoma, and glandular neoplasia, either in situ or invasive. The distinction among these various entities is not always easy, but guidelines are presented.