Microglandular hyperplasia: a model for the de novo emergence and evolution of endocervical reserve cells

Microglandular hyperplasia-like mucinous adenocarcinoma of the endometrium: A rare case report

BACKGROUND

Microglandular hyperplasia (MGH) is a proliferation of endocervical glands, related to estrogen stimulation, mainly occurring in the reproductive age group. The differential diagnosis includes endometrial adenocarcinoma with MGH-like pattern (MGA), a distinction that may be particularly problematic in curettage specimen.

CASE SUMMARY

A 57-year-old, postmenopausal woman was admitted in our hospital for surgical treatment. She had been diagnosed with a uterine leiomyoma, after complaints of irregular vaginal bleeding. She underwent dilatation and curettage (D&C) and subsequent total abdominal hysterectomy with bilateral salpingo-oophorectomy. D&C were compatible with MGA. Histologically, a proliferation of small glands, without intervening stroma, with mucin production, accumulation of neutrophils in the gland lumen and stroma, mild nuclear atypia and rare mitoses, were seen. In the hysterectomy specimen, the endometrium was thickened, but without apparent tumor formation. On microscopic examination, a residual similar adenocarcinoma was seen in the isthmus and more conventional-of endometrioid and mucinous type, in the rest of the endometrium.

CONCLUSION

MGH-like proliferation with mild cytologic atypia, detected in the endometrial curettage specimen of a postmenopausal woman, should alert pathologists for MGA of the endometrium. VIM, p16, PAX-2, CD10 and CD34 may help in the differential diagnosis.

Utility of p63 and PTEN Staining in Distinguishing Cervical Microglandular Hyperplasia from Endometrial Endometrioid Carcinoma with Microglandular/Mucinous Features

Aims

Distinction between well‐differentiated endometrial carcinoma (EMCA) with microglandular/mucinous features and benign endocervical microglandular hyperplasia (MGH) can be a diagnostic challenge, especially when tissue is limited. The immunostains used to distinguish endocervical and endometrial carcinoma are less useful when the differential diagnosis is MGH. Here, we investigate the utility of p63 and phosphatase and tensin homologue (PTEN) to aid accurate classification.

Methods and results

Cases obtained from our pathology archives included 25 EMCA with mucinous/microglandular features, 26 MGH and nine atypical microglandular proliferations. Cases were assessed for glandular architecture, presence of mucinous and/or eosinophilic luminal secretions, subnuclear vacuoles, foamy histiocytes, inflammation, squamous metaplasia, cytological atypia and mitotic activity. The presence and pattern of immunohistochemical staining for p63 and PTEN was recorded. Microglandular proliferations with cytological atypia, mitotic activity, foamy histiocytes and complex glandular architecture were more commonly seen in EMCA, while small glands, bland nuclei and subnuclear vacuoles were enriched in MGH. All MGH cases displayed p63‐positive subcolumnar reserve cells and retained PTEN expression. Four EMCA cases showed non‐specific focal p63 staining either at the surface of the tumour or in areas of squamous differentiation. p63 and PTEN immunostains accurately predicted the final diagnosis for 3 atypical microglandular proliferation cases with follow‐up.

Conclusions

While there are morphological characteristics that differentiate EMCA and MGH, there is frequent overlap between these entities. Nonetheless, the pattern and extent of p63 and PTEN can aid accurate classification. Consistent p63‐positive subcolumnar reserve cells were seen only in MGH.

Switches of SOX17 and SOX2 expression in the development of squamous metaplasia and squamous intraepithelial lesions of the uterine cervix

AIMS

The dynamics and topographical distribution of SOX17 and SOX2 expression was studied in the transformation zone (TZ) of the uterine cervix. This TZ is a dynamic area where switches from glandular into squamous epithelium can be recognized, new squamocolumnar junctions are formed, and premalignant lesions originate. SOX17 and SOX2 show mutually exclusive expression patterns in the normal uterine cervix, with SOX2 being exclusively found in squamous epithelium, while SOX17 is detected in endocervical columnar cells and reserve cells.

METHODS AND RESULTS

Normal cervices and squamous intraepithelial lesions (SIL) were studied with immunohistochemistry, methylation of SOX17, human papilloma virus (HPV) genotyping, and in situ hybridization. In the TZ squamous metaplasia originating from these reserve cells can still show SOX17 expression, while also remnants of SOX17-positive immature metaplasia can be recognized in the normal squamous epithelium. SOX17 expression is gradually lost during maturation, resulting in the exclusive expression of SOX2 in the majority of (SIL). This loss of SOX17 expression is independent of methylation of the CpG island in its promotor region. HPV can be detected in SOX17-positive immature metaplastic regions in the immediate vicinity of SOX2-positive SIL, suggesting that switches in SOX17 and 2 expression can occur upon HPV infection.

CONCLUSIONS

This switch in expression, and the strong association between the distribution of reserve cells and squamous areas within the columnar epithelium in the TZ, suggests that reserve cell proliferations, next to basal cells in the squamous epithelium, are potential targets for the formation of squamous lesions upon viral infection.

SOX17 expression and its down-regulation by promoter methylation in cervical adenocarcinoma in situ and adenocarcinoma

AIMS

SOX17 expression has not been studied in glandular lesions of the uterine cervix like adenocarcinoma in situ (AIS) and invasive adenocarcinomas (AdC), whereas SOX17 promoter CpG island methylation has been reported. Therefore, the aim of this study was to relate the topographical distribution of SOX17 expression and SOX17 methylation status to each other, and to SOX2 expression, human papillomavirus (HPV) type, and physical status of the virus.

METHODS AND RESULTS

Immunohistochemistry was used in 45 cases to assess expression of SOX17 and SOX2. SOX17 promoter methylation was determined in 25 cases by means of bisulphite conversion and methylation-specific polymerase chain reaction. SOX17 and SOX2 showed a mutually exclusive expression pattern in normal epithelium, with a sharp delineation in the squamocolumnar junction. SOX17 was found in endocervical columnar and reserve cells, whereas SOX2 was exclusively found in squamous epithelium. In both glandular lesions and cases with coexisting glandular and squamous intraepithelial components, a complex combination of SOX17 and SOX2 expression patterns was seen and mutually exclusive expression was lost. Frequently, gain of expression of SOX2 was found and expression of SOX17 was lost. Methylation of the CpG island in the SOX17 promoter was shown to be strongly associated with loss of expression of SOX17 (P = 0.0016).

CONCLUSIONS

In this study, we show for the first time a direct correlation between the topographical distribution of SOX17 expression and the methylation status of its gene promoter. This explains the heterogeneity of SOX17 expression in the glandular lesions of the cervix. No correlation was found between HPV type and physical status of the virus on the one hand and methylation status on the other.

Significance of DNA Replication Licensing Proteins (MCM2, MCM5 and CDC6), p16 and p63 as Markers of Premalignant Lesions of the Uterine Cervix: Its Usefulness to Predict Malignant Potential

Cervical cancer continues to be a leading cancer among women in many parts of the world. Nation-wide screening with the Pap smear has not been implemented in India due to the lack of adequately trained cytologists. Identification of biomarkers to predict malignant potential of the identified low risk lesions is essential to avoid excessive retesting and follow up. The current study analyzed the expression patterns of DNA replication licensing proteins, proliferation inhibitor protein p16INK4A and tumor suppresser protein p63 in cervical tissues and smears to assess the ability of these proteins to predict progression. Methods: Cervical smears and corresponding tissues were immunostained using mouse monoclonal antibodies against MCM2, MCM5, CDC6, p16 and p63. Smears were treated with a non-ionic surfactant sodium deoxycholate prior to immuno-cytochemistry. The standard ABC method of immunohistochemistry was performed using DAB as the chromogen. The immunostained samples were scored on a 0-3+ scale and staining patterns of smears were compared with those of tissue sections. Sensitivity and specificity for each of these markers were calculated taking histopathology as the gold standard. Result: All the markers were positive in malignant and dysplastic cells. MCM protein expression was found to be up-regulated in LSIL, HSIL and in malignancies to a greater extent than p16 as well as p63. CDC6 protein was preferentially expressed in high grade lesions and in invasive squamous cell carcinomas. A progressive increase in the expression of DNA replication licensing proteins in accordance with the grades of cervical intraepithelial lesion suggests these markers as significant to predict malignant potential of low grade lesions in cervical smears. Conclusion: MCMs and CDC6 can be applied as biomarkers to predict malignant potential of low grade lesions identified in screening programmes and retesting / follow up might be confined to those with high risk lesions alone so that overuse of resources can be safely avoided.

Keratin 17 Is a Prognostic Biomarker in Endocervical Glandular Neoplasia

OBJECTIVES

Previous work in our laboratory identified keratin 17 (K17) as a specific and sensitive biomarker for high-grade squamous intraepithelial lesions and cervical squamous cell carcinoma (SCC). K17, however, has not been previously evaluated in endocervical glandular neoplasia. Based on the similar pathogenesis of squamous and glandular lesions of the cervix, we hypothesized that K17 overexpression could also be a diagnostic and/or prognostic biomarker for endocervical neoplasia.

METHODS

Cases of endocervical adenocarcinoma (n = 90), adenocarcinoma in situ (AIS) (n = 32), benign glandular lesions (n = 36), and normal endocervical mucosa (n = 5) were selected from Stony Brook Medicine and the University of Massachusetts from 2002 to 2013. Immunohistochemical staining for K17 was performed by an indirect immunoperoxidase method and was scored based on the proportion of cells that showed strong (2+) staining.

RESULTS

K17 was highly expressed in 21 (65.6%) of 32 AIS and in 75 (83.0%) of 90 adenocarcinoma cases. In adenocarcinomas, K17 staining was detected in a mean of 33.9% of malignant cells. Staining tended to be strongest at the periphery of pseudoglandular groups and at the invasive front of tumors. K17 was not detected in the epithelial cells of benign glandular lesions, but groups of cuboidal cells, residing beneath the epithelial layer of benign glands, were frequently positive for K17, especially in cases of microglandular hyperplasia. High levels of K17 expression were significantly associated with decreased patient survival.

CONCLUSIONS

K17 is highly expressed in most cases of both invasive adenocarcinoma and in AIS and is a powerful, negative prognostic marker for patient survival.

Deciphering the Multifactorial Susceptibility of Mucosal Junction Cells to HPV Infection and Related Carcinogenesis

Human papillomavirus (HPV)-induced neoplasms have long been considered to originate from viral infection of the basal cell layer of the squamous mucosa. However, this paradigm has been recently undermined by accumulating data supporting the critical role of a discrete population of squamo-columnar (SC) junction cells in the pathogenesis of cervical (pre)cancers. The present review summarizes the current knowledge on junctional cells, discusses their high vulnerability to HPV infection, and stresses the potential clinical/translational value of the novel dualistic model of HPV-related carcinogenesis.

Claudin 1 expression characterizes human uterine cervical reserve cells

Stem cells participate in cervical carcinogenesis but their function and exact features are still not clear. One type of stem-like cells are endocervical reserve cells (RCs), and their association with other normal/altered cervical cells is not exactly known. Epithelial cells are attached to each other by tight junctions. Their dominant components are the claudin proteins, which show changed expression in cancer; however, no data are available on their pattern. Expressions of various claudins (1, 2, 3, 4, 7), occludin, cytokeratins 5/6 and 7, and p63 were analyzed in 60 paraffin-embedded cervical samples. Immunohistochemical reactions were evaluated semiquantitatively and statistically. Claudin 1 was as high in RCs as in cervical intraepithelial neoplasia (CIN) and higher than in suprabasal squamous epithelial cells, contrary to the negative glandular and squamous basal cells. Claudin 2 was positive in all cell types except parabasal cells, whereas claudins 4 and 7 were weakly positive and claudin 3 was negative in all cell types. Occludin was positive in RCs, basal/parabasal cells, and CIN, whereas glandular cells were negative. This is a first report that describes the intermediate claudin pattern of RCs, demonstrating that it differs from that of cervical glandular and squamous basal cells, but showing an expression similar to the strong claudin 1 expression detected in cervical neoplastic cells.

A novel blueprint for 'top down' differentiation defines the cervical squamocolumnar junction during development, reproductive life, and neoplasia

The cervical squamocolumnar (SC) junction is the site of a recently discovered 'embryonic' cell population that was proposed as the cell of origin for cervical cancer and its precursors. How this population participates in cervical remodelling and neoplasia is unclear. In the present study, we analysed the SC junction immunophenotype during pre- and post-natal human and mouse development and in the adult, processes of metaplastic evolution of the SC junction, microglandular change, and early cervical neoplasia. Early in life, embryonic cervical epithelial cells were seen throughout the cervix and subsequently diminished in number to become concentrated at the SC junction in the adult. In all settings, there was a repetitive scenario in which cuboidal embryonic/SC junction cells gave rise to subjacent metaplastic basal/reserve cells with a switch from the SC junction positive to negative immunophenotype. This downward or basal (rather than upward or apical) evolution from progenitor cell to metaplastic progeny was termed reverse or 'top down' differentiation. A similar pattern was noted in high-grade squamous intraepithelial lesions (HSILs), suggesting that HPV infection of the cuboidal SC junction cells initiated outgrowth of basally-oriented neoplastic progeny. The progressive loss of the embryonic/SC junction markers occurred with 'top down' differentiation during development, remodelling, and early neoplasia. Interestingly, most low-grade SILs were SC junction-negative, implying infection of metaplastic progeny rather than the original SC junction cells. This proposed model of 'top down' differentiation resolves the mystery of how SC junction cells both remodel the cervix and participate in neoplasia and provides for a second population of metaplastic progeny (including basal and reserve cells), the infection of which is paradoxically less likely to produce a biologically aggressive precursor. It also provides new targets in animal models to determine why the SC junction is uniquely susceptible to carcinogenic HPV infection.

Laboratory management of cervical intraepithelial neoplasia: proposing a new paradigm

Since the discovery of human papillomavirus (HPV) type 16 in early 80s, the link between HPV and cervical cancer has been established with certainty, a function of the discovery and cloning of a range of HPV types associated with both cancer precursors (cervical intraepithelial neoplasia or CIN) and carcinomas and extensive epidemiologic, clinical, pathologic, and experimental data. These accumulated results have culminated in new paradigms of cancer prevention through screening and triage. Despite this, the management of women with CIN is still suboptimal and the overtreatment of these conditions still occurs, largely due to the lack of clarity regarding which precancerous lesions are most likely to progress in grade. Recently, a discrete population of cuboidal cells was discovered at the cervical squamocolumnar junction, the anatomic site where the large majority of HPV-related (pre)neoplastic lesions develop. These cells seem to be embryonic in nature and participate both in benign metaplasias and the initial phase of precancer development. This review summarizes the historical evolution of precursor management, assesses the potential role of this and other discoveries in segregating lower from higher-risk precursors, and examines their potential impact on the management of women with real or potential cervical cancer precursors.

P634A4 and TAp73 immunocytochemistry in liquid-based cervical cytology--potential biomarkers for diagnosis and progress prediction of cervical neoplasia

P63 and p73 are two homologues of the important tumor suppressor gene p53. In this study, we investigated p63 and p73 expression by immunocytochemistry using antibodies for TAp73 and p634A4 isoforms in 91 high-grade and 107 low-grade squamous intraepithelial lesions, 212 atypical squamous cells of undetermined significance, 9 squamous cell carcinomas and 63 normal samples from an Asian screening population together with 47 hospital samples of carcinomas. There was significant correlation between the TAp73 and p634A4 indices (P<0.0001). Significantly, higher TAp73 and p634A4 indices were found in high-grade lesions or carcinoma when compared with atypical squamous cells and low-grade lesions (P<0.0001). Among atypical squamous cells, p634A4 indices of cases that subsequently progressed to low-grade (P=0.031) or high-grade lesions (P=0.006) were significantly higher than those that did not. For atypical squamous cells positive for high-risk human papillomavirus (HPV) as detected by Digene (61%), cases with high p634A4 index were still more likely to have subsequent high-grade lesions detected (P=0.016). Among low-grade lesions, significantly higher TAp73 (P=0.038) was found in cases that subsequently progressed to high-grade lesions. There was significant correlation between presence of high-risk HPV and p634A4 index (P=0.01). In summary, p63 and p73 immunocytochemistry are potential good markers for detection of carcinoma and high-grade lesions in cervical cytology samples and for triage management of women with atypical squamous cells and low-grade lesions.

p63 in epithelial survival, germ cell surveillance, and neoplasia

The p53homolog p63has emerged as a gene with an enormously complex function that is distinct from that of p53. It encodes two distinct transcript isoforms that have a dramatic impact on replenishment of cutaneous epithelial stem cells and on ovarian germ cell survival. However, although these two fundamental roles of p63 attest to its powerful place in development, its other functions-specifically the apparent capacity of p63, when induced, to supervise the emergence of new cell populations in the breast, prostate, cervix, and upper reproductive tract-are shared by embryo and adult. These observed functions may only scratch the surface of a repertoire that has been postulated to encompass a range of cellular activities, as evidenced by the fact that p63 proteins have been shown to potentially bind to over 5800 target sites. Whether tumorigenic pathways are also involved, and to what extent, is a subject of both promise and controversy that remains to be resolved.

Distribution pattern and marker profile show two subpopulations of reserve cells in the endocervical canal

SUMMARY

A previous immunophenotyping study in the fetal uterine cervix provided evidence for the existence of 2 subpopulations of reserve cells, one giving rise to glandular epithelium and the other to squamous epithelium (5). In this study, we investigated whether the adult uterine cervix also harbors different populations of reserve cells on the basis of their marker profile and distribution pattern. Sagittal sections from 10 normal uteri, comprising the region from ectocervix to lower uterine cavity, were histologically examined and immunostained for p63, bcl-2 and cytokeratins (CKs) 5, 7, 8, and 17. The endocervical canal consists of three regions, that is, a part lined with squamous epithelium, a part lined with endocervical cells and a part lined with tubal type epithelial cells. Histologically, we found reserve cells in all 10 investigated cervices, with an abundancy in the area beneath the endocervical columnar epithelium close to the squamo-columnar junction, and high in the endocervical canal where the invaginations consist of tubal type epithelium. In between, an area lined with endocervical columnar cells without reserve cells was identified. No reserve cells were detected in the endometrial epithelium. We defined the end of the endocervix as the point where the surface of the cervical canal and the invaginations are completely lined with tubal type epithelium. From this point, reserve cells were no longer found. Reserve cells show strong expression for p63, CKs 5 and 7, and moderate expression for bcl-2. CK17 is strongly expressed in the reserve cells at the squamo-columnar junction and to a lesser extent in the reserve cells close to the endometrium. Endocervical columnar cells usually express CKs 7 and 8 and sporadically also p63 and CK5. CK17 was only found in endocervical cells in the vicinity of CK17-positive subcolumnar reserve cells. Tubal-type epithelium was present in all samples and contained bcl-2, along with CKs 5, 7, and 8. As a result, bcl-2 and CK5 expression distinguishes tubal epithelium from endocervical columnar cells. We conclude that reserve cells are present in all investigated cervices along the entire cervical canal. The concentration of subglandular reserve cells is highest close to the squamo-columnar junction and in the upper third of the cervix. The marker profile of reserve cells is the same in all parts of the cervix, except for CK17, which shows a decreasing gradient from distal to proximal, indicating a subpopulation of distal reserve cells as progenitor for squamous and columnar epithelium, and proximal reserve cells that can serve as progenitor cells for columnar epithelium.

The expression and diagnostic utility of p63 in the female genital tract

p63 plays a key role in epithelial development in various organs, being expressed in myoepithelial cells and in basal cells of stratified epithelia. In the female genital tract, p63 is expressed in the basal and parabasal cells of mature cervical, vaginal and vulval squamous epithelium, and also in cervical reserve cells at the transformation zone and in immature metaplastic and atrophic cervical squamous epithelium. In this review, the diagnostic utility of p63 immunohistochemical staining in various pathologic scenarios within the female genital tract is discussed. Cervical microglandular hyperplasia is p63 positive with a characteristic subcolumnar location due to expression in reserve cells. There is increased expression in cervical intraepithelial neoplasia, in accordance with the degree of dysplasia. One of the most useful applications of p63 is in the evaluation of problematic cervical carcinomas; most squamous carcinomas exhibit diffuse nuclear immunoreactivity whereas most adenocarcinomas and neuroendocrine carcinomas are negative or focally positive. In conjunction with neuroendocrine markers, p63 is useful in distinguishing between a squamous carcinoma and a small cell or large cell neuroendocrine carcinoma. In the normal endometrium, a population of p63-positive cells is present which may act as a stem cell population and which is increased in various forms of metaplasia. Placental site nodule and epithelioid trophoblastic tumor (lesions derived from chorionic-type intermediate trophoblast) are usually p63 positive whereas placental site reaction and placental site trophoblastic tumor (lesions derived from implantation site intermediate trophoblast) are usually negative; thus, p63 may be useful in the diagnostic algorithm of trophoblastic lesions. p63 positivity in ovarian epithelial tumors is uncommon and largely restricted to squamous and transitional neoplasms, including benign and borderline Brenner tumor. p63 is also positive in cervical transitional metaplasia, Walthard rests, vulval Paget disease secondary to an underlying urothelial malignancy, tubulosquamous polyp of the vagina, and ectopic prostatic tissue in the cervix.

Reserve Cells in Human Uterine Cervical Epithelium Are Derived from Müllerian Epithelium at Midgestational Age

The role of endocervical reserve cells in squamous metaplasia and neoplasia is still debated. Their origin in the cervix is open to speculation and it is unclear how they are targeted during carcinogenesis. To further understand the primary characteristics of reserve cells, we phenotyped them in the developing human cervix. In 13 perinatal autopsies of fetuses between 16 and 40 weeks of gestation, the human fetal cervix was evaluated in serial sections. Immunostaining comprised a panel of antibodies for cytokeratins, p63, and bcl-2; then, the sections were stained with Alcian blue and periodic acid-Schiff before and after diastase treatment. Reserve cells are first identified at approximately 20 weeks of gestation. They are first noted under müllerian-type columnar cells lining the developing uterine cavity. There is considerable overlap in the expression profiles of müllerian cells and reserve cells for p63, bcl-2, and cytokeratins 5, 8, and 18 at this stage of development, with increasing gestational age expression localized to respective cell compartments. Eventually, the phenotype of these cells correspond fully with that described for adult reserve cells and endocervical cells. Müllerian epithelial cells are the stem cell for endocervical reserve cells and endocervical columnar cells. They have the capacity to transform into both endocervical columnar and squamous-type epithelium in the endocervix during early cervical development.

CK17 and p16 expression patterns distinguish (atypical) immature squamous metaplasia from high-grade cervical intraepithelial neoplasia (CIN III)

Regauer S & Reich O (2007) Histopathology50, 629–635 CK17 and p16 expression patterns distinguish (atypical) immature squamous metaplasia from high-grade cervical intraepithelial neoplasia (CIN III)

Role of hormone cofactors in the human papillomavirus-induced carcinogenesis of the uterine cervix

If human papillomavirus (HPV) is necessary for the development of (pre)neoplastic lesions of the uterine cervix, it is not sufficient. Among the cofactors involved in the malignant transformation of cells infected by HPV, sex hormones may facilitate the cervical carcinogenesis by different mechanisms, including the induction of squamous metaplasia in the transformation zone of the cervix, interactions between steroid hormones and HPV gene expression and alterations of the local immune microenvironment.

Redefining early cervical neoplasia: recent progress

The classification of cervical precancers has evolved over the past 40 years as knowledge concerning the pathogenesis of these human papillomavirus-related lesions has expanded. This commentary reviews the current classification scheme in light of (1) the historical classification systems and (2) the ability of the target epithelium, that is the transformation zone to exhibit varied morphology depending on the cell type that is infected with human papillomavirus. The evolution in our understanding of preinvasive glandular neoplasia is also summarized, with particular attention to so-called superficial (or early) adenocarcinoma in situ. In addition, practical issues in the diagnosis and management of squamous epithelial lesions, particularly the recognition of nonconventional variants and the application of biomarkers, are discussed.

Superficial (early) endocervical adenocarcinoma in situ: a study of 12 cases and comparison to conventional AIS

Although established histologic criteria for the diagnosis of endocervical adenocarcinoma in situ (AIS) have been published, some lesions are not readily classified or present with more subtle degrees of epithelial atypia. Lesions confined to the surface mucosa may be particularly challenging, possibly because they represent early disease. Twelve cases of superficial AIS (SAIS) confined to the surface mucosa or crypt openings culled from the in-house and consultation practices were examined histologically, immunostained for MIB-1 and p16, and analyzed (when possible) for HPV nucleic acids by DNA-DNA in situ hybridization (INFORM). The mean age was 26.7 years for SAIS versus 37.0 years for 42 consecutive cases of conventional AIS from the same practice (P < 0.001). Seven and five were biopsies and conization specimens, respectively. Five coexisted with CIN, four arose in endocervical papillae, and two arose in endocervical polyps. Nuclear hyperchromasia was conspicuous in 10 and mitoses were present in all; however, apoptosis was rare or absent in four, and six exhibited only mild nuclear atypia. Mib-1 staining exceeded 40% in 5 of 7 cases tested, and all (8 of 8) were strongly positive for p16(ink4). Five of five were positive for HPV by ISH with an "integrated" dot-like pattern. SAIS is an early variant of AIS that 1) occurs at a younger mean age, 2) exhibits variable atypia, and 3) arises adjacent to morphologically normal columnar epithelium. Diffuse p16 expression and integrated HPV pattern are identical to that seen in more extensive forms of the disease. Superficial AIS should be suspected in endocervical columnar epithelium with segmental nuclear hyperchromasia with mitotic activity, and confirmed by biomarker staining (p16 and Mib-1) if the pathologist is uncertain of the diagnosis.