Immunohistochemistry as a diagnostic aid in cervical pathology

Utilization of immunohistochemistry in gynecologic tumors: An expert review

The use of immunohistochemistry (IHC) and molecular pathology has been widely adopted over the past 3 decades and has aided in the precision of diagnosing gynecologic tumors. While many tumors can be diagnosed by histologic appearance on routine hematoxylin and eosin stained slides, the use of IHC has dramatically changed practice, leading to a better understanding and subtyping of gynecologic tumors. This detailed classification of tumors has aided in the implementation and development of targeted therapies. Available IHC stains and their applications continue to rapidly evolve. Our review aims to provide updated information on the use of IHC in gynecologic tumors. We will also address the rationale for preferred therapeutic regimens that are personalized based on IHC.

The evolving landscape of immunohistochemistry in cervical and uterine carcinoma in gynecologic oncology: current status and future directions

Immunohistochemistry (IHC) has become an indispensable tool in routine gynecological pathology, particularly with the advancements in molecular understanding and histological classification of gynecological cancers. This evolution has led to new immunostainings for diagnostic and classification purposes. This review describes the diagnostic utility of IHC in gynecological neoplasms, drawing insights from literature reviews, personal experiences, and research findings. It delves into the application of IHC in resolving morphologically equivocal cases, emphasizing its role in achieving an accurate diagnosis. The selection of appropriate immunomarkers for common scenarios encountered in gynecological pathology aids pathologists in navigating complex cases. Specifically, we focus on cervical and endometrial malignancies, elucidating the molecular rationale behind the use of specific immunohistochemical markers. An updated overview of essential immunohistochemical markers provides knowledge for precise diagnosis and classification of gynecological cancers. This review serves as a valuable resource for clinicians and researchers involved in the management and study of gynecological malignancies, facilitating improved patient care and outcomes.

Unusual spread of cervical adenocarcinoma to the endometrium and left fallopian tube: a case report and literature review

Introduction

The incidence of cervical adenocarcinoma and adenocarcinoma in situ are gradually increasing especially in younger women. However, unusual spread of cervical adenocarcinoma has rarely been reported.

Case presentation

The authors report a case of a 60-year-old woman who presented with postmenopausal bleeding. She was misdiagnosed to have endometrial adenocarcinoma on the lower uterine segment depending on curettage specimen. After hysterectomy, it was revealed depending on morphological features in histology accompanied with immunohistochemistry that the patient had cervical adenocarcinoma with endometrial and left fallopian tube extension.

Discussion

Distinguishing endocervical adenocarcinoma from endometroid adenocarcinoma poses many challenges especially when evaluating endometrial curettage specimens. Histological diagnosis based on morphological features combined with a panel of immunohistochemistry stains is crucial for accurate diagnosis and identifying the primary origin of the tumor.

Conclusion

Accurate distinction between cervical adenocarcinoma versus endometrial adenocarcinoma is important because of its significant effects on choosing the appropriate treatment option.

Can CAPRIN-1 Be Responsible for the Recurrence Potential of Odontogenic Keratocysts?

Objectives

The purpose of this retrospective study is to compare dentigerous cysts and odontogenic keratocysts for cytoplasmic activation/proliferation - associated protein-1 antibodies via immunohistochemical staining to obtain a new perspective about the specific behavioural characteristics of odontogenic keratocysts at the molecular level.

Material and Methods

Forty dentigerous cysts (DC) and forty odontogenic keratocysts (OKC) tissue samples were examined using immunohistochemical staining to detect cytoplasmic activation/proliferation - associated protein-1 (CAPRIN-1) antibodies. Nuclear and/or cytoplasmic staining was evaluated as "positive". Cell staining rate (%) and cell staining intensity were determined, and a staining intensity distribution (SID) score was calculated for each sample. Cases were considered "negative" if they showed no staining for CAPRIN-1 antibodies, thus were given a SID score of zero. According to the SID scores, the expression levels were rated as negative, mild, moderate, or high.

Results

Of 80 samples, 16 that could adversely affect immunohistochemical evaluation were excluded. Ten negative, 21 positive and three negative, 30 positive CAPRIN-1 expressions were observed in DC and OKC groups, respectively. The difference between the negative and positive cases within groups was significant only in the OKC group (P = 0.000). The SID score range and mean were 0 to 160 and 31.1 (SD 35.7) for DC and 0 to 160 and 57.3 (SD 42.3) for OKC groups. CAPRIN-1 expression was significantly higher in the OKC group (P = 0.043).

Conclusions

The molecular basis for increased mitotic activity, high recurrence rates or presence of satellite cysts in odontogenic keratocysts may be attributed to the expression of cytoplasmic activation/proliferation - associated protein-1.

A Spectrum of Metastases to the Breast: Radiologic-Pathologic Correlation

Metastases to the breast from non-mammary origin are rare. The majority of these lesions appear as secondary manifestations of melanoma and lymphoma, followed by lung carcinomas, gynecological carcinomas, and sarcomas. There has been a steady trend of an increase in diagnosis of intramammary metastases owing to the current advances in imaging technology. Imaging features depend on the type of primary neoplasm and route of dissemination, some of which resemble primary breast cancer and benign breast entities. There are certain imaging features that raise the level of suspicion for metastases in the correct clinical context. However, imaging manifestations of intramammary metastases do not always comply with the known classic patterns. The aim of this review is to clarify these features, emphasizing radiologic-pathologic correlation and a multidisciplinary approach, since most cases are found in patients with advanced disease.

Histological analysis of TGFβ1 and VEGFR expression in cervical carcinoma treated with Rhodomyrtus tomentosa

Cervical carcinoma is one of the most common malignant carcinomas around the world, including Indonesia. Rhodomyrtus tomentosa is an herbal medicine that is often used in Asia as a therapeutic agent to stop cancer metastases. The process of neoangiogenesis in cervical cancer depends on VEGFR activity. Increased TGFβ1 production is also linked to cervical cancer, suggesting that gene inactivation contributes to the emergence of cervical carcinoma.

Group C- was the control group, Group C+ was the cancer model group, CER100 was the group of rats with cancer + 100 mg/kg body weight (BW) of R. tomentosa, CER200 was the group of rats with cancer + 200 mg/kg BW of R. tomentosa, and CER400 was the group of rats with cancer + 400 mg/kg BWR. tomentosa. Rats were dissected after administration of R. tomentosa for 30 days. Immunohistochemical staining of the cervical tissue was performed with TGFβ1 and VEGFR antibodies. VEGFR expression was significantly different from TGFβ1 expression (p < 0.01). The highest expression was observed at the lowest dose of R. tomentosa (100 mg/kg BW), and the lowest expression was observed at 200 and 400 mg/kg BW. The administration of R. tomentosa can repair tissue damage and decrease the expression of TGFβ1 and VEGFR via histopathological parameters, indicating the importance of the activity of these proteins in the development of neoangiogenesis in cervical cancer.

PDGF-β and IL-18 Expressions on Carcinoma Cervical by Rhodomyrtus tomentosa

&lt;b&gt;Background and Objective:&lt;/b&gt; Cervical cancer, along with lung and breast cancer, is one of Indonesia's most aggressive gynaecological diseases. &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; has antioxidant and antiproliferative properties that could be developed into herbal medicines for molecular therapy. The IL-18 and PDGF-β are tumour-promoting agent proteins that may be therapeutic targets for a variety of cancers that were investigated in this study. &lt;b&gt;Materials and Methods:&lt;/b&gt; Rats were classified into five groups: Group C- is the control group, Group C+ is the cancer model group and Group RHO200 is the &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; 100 mg&lt;sup&gt;1&lt;/sup&gt; b.wt., rat group, Group RHO400 is the &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; 200 mg&lt;sup&gt;1&lt;/sup&gt; b.wt., rat group and Group RHO400 is the &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; 400 mg&lt;sup&gt;1&lt;/sup&gt; b.wt., rat group. The rats were dissected 30 days after receiving &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt;. Immunohistochemistry is used to stain cervical tissues. &lt;b&gt;Results:&lt;/b&gt; The expression of IL-18 and PDGF-β was significantly different (p<0.01). The IL-18 and PDGF-β were most abundant at the lowest &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; doses (100-200 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt.), while they were least abundant at the 400 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt., doses. Histological analysis revealed that the highest dose of IL-18 and PDGF-β expression reduced abnormal tissue and the space between tumours, followed by several carcinoma cells that stopped growing. &lt;b&gt;Conclusion:&lt;/b&gt; &lt;i&gt;Rhodomyrtus tomentosa&lt;/i&gt; can be used as a herbal therapy to reduce the expression of PDGF-β and IL-18 (two cancer marker agents).

Gastric-type endocervical adenocarcinoma with mucoepithelial metaplasia combined with a serous borderline tumor: A case report

RATIONALE

Gastric-type endocervical adenocarcinoma (GAS) is a rare type of cervical adenocarcinoma that is a mucinous adenocarcinoma with a variety of gastral patterns. To date, there are no systematic clinical diagnosis and treatment guidelines.

PATIENT CONCERNS

In our case, a 49-year-old woman underwent pelvic magnetic resonance imaging (MRI) due to a pelvic mass, and cervical lesions were unexpectedly found. After receiving relevant surgical treatment, the pathological results showed the particularity of the tumor type-cervical gastric adenocarcinoma with a borderline serous tumor of both appendages and the right ovary.

DIAGNOSES

Postoperative routine pathological examination showed mucoepithelial metaplasia accompanied by a borderline serous tumor.

INTERVENTIONS

After gynecological/urinary ultrasound, blood tests, MRI, cervical biopsy, and uterine curettage, "robot-assisted laparoscopic radical hysterectomy + bilateral salpingectomy-ovariectomy + pelvic lymph node dissection + pelvic adhesiolysis" were performed. After the surgery, the patient was treated with radiotherapy and concurrent chemotherapy.

OUTCOMES

After the operation, radiotherapy, and chemotherapy, the patient had no tumor recurrence and is still in good condition.

LESSONS

The diagnosis of GAS is relatively difficult, its clinical manifestations lack specificity, and the pathogenesis has nothing to do with human papillomavirus infection. The patient was misdiagnosed with vaginitis at a local hospital. However, we found that MRI and pathological examination were helpful for the diagnosis of the disease. Although there are no relevant guidelines to explain the treatment principles of GAS, we believe that early surgery is conducive to the prognosis of the disease because GAS has a certain tolerance to radiotherapy and chemotherapy.

Cervical squamous cell carcinoma metastasis to the breast - A case report from Uganda Cancer Institute

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Cervical squamous cell carcinoma does metastasize to the breast.

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Vagina exam is essential in a patient who presents with a breast mass.

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Immunohistochemistry is key in differentiating a primary lesion from a metastasis.

Immunohistochemistry in gynecologic carcinomas: Practical update with diagnostic and clinical considerations based on the 2020 WHO classification of tumors

This review provides an update on immunohistochemistry applications-diagnostic, prognostic, and predictive-in the pathology evaluation of gynecologic carcinomas. The 5th edition of the WHO Classification of Female Genital Tumors introduced important changes in the diagnostic classification of lower genital tract, endometrial, and ovarian carcinomas, with major influence on the routine pathology practice. Lower genital tract carcinomas and their precursor lesions are now classified based on their human papillomavirus (HPV)-associated and HPV-independent pathogenesis, reflecting the clinically significant prognostic differences and impacting the therapeutic decision-making. Immunohistochemical markers have an increasing role in the pathology evaluation of endometrial carcinomas: in addition to their traditional use in the differential diagnosis and histologic subtyping, they have also been recently advocated for prognostic classification as surrogates for the TCGA (The Cancer Genome Atlas) molecular groups. New entities - mesonephric-like adenocarcinoma and gastric (gastrointestinal)-type mucinous adenocarcinoma of the endometrium - have also been added and often require immunostains for diagnostic confirmation. Ovarian carcinomas frequently show overlapping morphologic patterns and heterogeneous appearance within the same tumor, necessitating immunohistochemical work-up. Beyond diagnostic applications, there is increasing clinical demand for screening of inherited cancer syndromes, prediction of prognosis and guiding targeted therapy. Practical issues and pitfalls related to mismatch repair protein immunohistochemistry, HER2, and PD-L1 testing are also discussed.

DDX41 regulates the expression and alternative splicing of genes involved in tumorigenesis and immune response

DEAD‑box helicase 41 (DDX41) is an RNA helicase and accumulating evidence has suggested that DDX41 is involved in pre‑mRNA splicing during tumor development. However, the role of DDX41 in tumorigenesis remains unclear. In order to determine the function of DDX41, the human DDX41 gene was cloned and overexpressed in HeLa cells. The present study demonstrated that DDX41 overexpression inhibited proliferation and promoted apoptosis in HeLa cells. RNA‑sequencing analysis of the transcriptomes in overexpressed and normal control samples. DDX41 regulated 959 differentially expressed genes compared with control cells. Expression levels of certain oncogenes were also regulated by DDX41. DDX41 selectively regulated the alternative splicing of genes in cancer‑associated pathways including the EGFR and FGFR signaling pathways. DDX41 selectively upregulated the expression levels of five antigen processing and presentation genes (HSPA1A, HSPA1B, HSPA6, HLA‑DMB and HLA‑G) and downregulated other immune‑response genes in HeLa cells. Additionally, DDX41‑regulated oncogenes and antigen processing and presentation genes were associated with patient survival rates. Moreover, DDX41 expression was associated with immune infiltration in cervical and endocervical squamous cancer. The present findings showed that DDX41 regulated the cancer cell transcriptome at both the transcriptional and alternative splicing levels. The DDX41 regulatory network predicted the biological function of DDX41 in suppressing tumor cell growth and regulating cancer immunity, which may be important for developing anticancer therapeutics.

The Evolving Spectrum of Precursor Lesions of Cervical Adenocarcinomas

Modern classification schemes divide cervical adenocarcinomas into human papillomavirus (HPV)-associated and HPV-independent types. The precursor lesions of the former are well known and comprise HPV-associated (usual/endocervical) adenocarcinoma in situ (AIS) and the much less common stratified mucin-producing intraepithelial lesion (SMILE). The precursor lesions of HPV-independent cervical adenocarcinomas are much less well known, although postulated precursors of gastric-type adenocarcinoma include atypical lobular endocervical glandular hyperplasia and gastric-type AIS. In this review, we cover HPV-associated and HPV-independent precursor lesions of cervical adenocarcinomas concentrating on diagnostic criteria (morphology and immunophenotype) and differential diagnosis. We propose a uniform terminology and diagnostic criteria for precursor lesions showing intestinal differentiation with goblet cells because this may be a feature of both HPV-associated and HPV-independent AIS.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Immunohistochemistry in Gynecologic Pathology: An Example-Based Practical Update

CONTEXT

- Immunohistochemical stains are routinely applied in the pathology diagnostic workup of gynecologic lesions. The rapidly expanding repertoire of available markers helps in refining the diagnostic criteria for each disease entity; however, limitations and pitfalls exist.

OBJECTIVE

- To provide a practical, relevant update on the use of immunohistochemistry for commonly encountered differential diagnoses in gynecologic pathology.

DATA SOURCES

- Literature review and authors' diagnostic experience.

CONCLUSIONS

- Immunohistochemistry is a helpful adjunct tool in gynecologic pathology. Although the primary application is in the diagnostic workup, novel prognostic and predictive markers, and immunostains to screen for genetic cancer syndromes, have also been recently introduced in the field.

PTD4-apoptin induces Bcl-2-insensitive apoptosis in human cervical carcinoma in vitro and in vivo

Worldwide, cervix carcinoma is among the most dangerous cancer types, and novel therapies are under development. Cancer treatments are often hampered because of lack of specificity. The chicken anemia virus-derived apoptin induces apoptosis selectively in tumor cells and leaves normal cells unharmed. Here, we have carried out in-vitro and in-vivo studies on the cytotoxic effect of apoptin in a cervix carcinoma model. Apoptin was fused to the protein transduction domain 4 (PTD4), enabling delivery of the fusion protein across cellular membranes. PTD4-apoptin protein is located in the nuclei of human cervical carcinoma HeLa cells and in the cytoplasm of normal cells L02. By MTT and flow cytometry analysis, we have proven that PTD4-apoptin protein induced apoptosis in the cervical carcinoma cells. PTD4-apoptin enhanced the level of active executioner caspase-3. Neither caspase-3 activation nor apoptin-induced accumulation of the mitochondrial outer-membrane protein Mfn-2 was affected by ectopic Bcl-2 expression. In contrast, apoptin-mediated AKT activation was inhibited by Bcl-2. In vivo, cervix carcinoma xenografts were treated for 7 days with PTD4-apoptin protein. The PTD4-apoptin treatment induced a decrease in the cervix carcinoma, whereas the PTD4-GFP protein-treated controls expanded significantly. TUNEL analysis showed that PTD4-apoptin protein induced apoptosis in cervix carcinoma cells, in contrast to the control PTD-GFP-treated ones. Our results indicate that apoptin is a potential anticancer agent for treating cervix carcinoma.

Metastasis of cervical cancer to breast: A case report and review of literature

Metastasis to the breast from an extra-mammary malignancy has been documented in literature, however cervical cancer metastasis to the breast is very rare. Thirty-eight cases of metastatic deposit to the breast from cervical cancer have been reported in literature. Though most patients present with a breast lump, it is very difficult to clinically distinguish a primary breast malignancy from a metastatic deposit. Histopathology of the tissue, aided with immune-histochemical staining pattern provides a definitive diagnosis. Our patient, a 51-year old woman presented with breast lump and history of post-menopausal bleeding. Upon further workup, the patient was diagnosed with cervical cancer. The mammogram and ultrasound of the breast showed multiple lumps within the breast. Histopathology of the breast mass showed metastatic deposit in the breast from cervical cancer. The patient was treated with radiation therapy to the cervix along with concurrent chemotherapy for local control of pain. After completion of local treatment, she started systemic chemotherapy, however she developed health-care associated pneumonia and subdural hematoma leading to deterioration in her performance status. The patient opted for hospice care and died 2 months later. In this report, we will review the presentation of the 38 cases reported in literature and the imaging and histopathologic findings of metastatic deposits to the breast.

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Metastasis to the breast foretells a poor prognosis.

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Histopathology and immuno-histochemistry are quintessential in diagnosing metastasis.

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All breast lumps are first primary breast cancer unless proven otherwise.

Efficacy of p16 and Ki-67 immunostaining in the detection of squamous intraepithelial lesions in a high-risk HPV group

p16 and Ki-67 immunohistochemistry can be used as an ancillary method for the diagnosis of squamous intraepithelial lesion (SIL) versus atrophic change and atypical squamous metaplasia. The aim of the present study was to evaluate the efficacy of these two immunohistochemical markers in the accurate interpretation of cervical biopsies and correlate this data with human papilloma virus (HPV) infection status. The study included 103 formalin-fixed cervical punch and cone biopsy samples, with corresponding HPV DNA test data. Histopathological staining with hematoxylin and eosin, and immunohistochemical staining for p16 and Ki-67 were reviewed by two pathologists. The positivity of p16 and Ki-67 increased significantly with the severity of the cervical lesion in patients with a high-risk-HPV (HR-HPV) infection status (P<0.001). However, there was discordance in the HPV-negative group. Furthermore, concomitant diffuse, strong and block positive staining of p16, and a high Ki-67 index were implicated in high-grade SIL in the HR-HPV group. Thus, the two markers were efficient in advancing the diagnostic accuracy of cervical biopsies in the HR-HPV group; however, application of immunohistochemical results should be carefully considered in the HPV-negative group.

Efficacy of p16 and Ki-67 immunostaining in the detection of squamous intraepithelial lesions in a high-risk HPV group

p16 and Ki-67 immunohistochemistry can be used as an ancillary method for the diagnosis of squamous intraepithelial lesion (SIL) versus atrophic change and atypical squamous metaplasia. The aim of the present study was to evaluate the efficacy of these two immunohistochemical markers in the accurate interpretation of cervical biopsies and correlate this data with human papilloma virus (HPV) infection status. The study included 103 formalin-fixed cervical punch and cone biopsy samples, with corresponding HPV DNA test data. Histopathological staining with hematoxylin and eosin, and immunohistochemical staining for p16 and Ki-67 were reviewed by two pathologists. The positivity of p16 and Ki-67 increased significantly with the severity of the cervical lesion in patients with a high-risk-HPV (HR-HPV) infection status (P<0.001). However, there was discordance in the HPV-negative group. Furthermore, concomitant diffuse, strong and block positive staining of p16, and a high Ki-67 index were implicated in high-grade SIL in the HR-HPV group. Thus, the two markers were efficient in advancing the diagnostic accuracy of cervical biopsies in the HR-HPV group; however, application of immunohistochemical results should be carefully considered in the HPV-negative group.

GATA3 Is a Sensitive and Specific Marker of Benign and Malignant Mesonephric Lesions in the Lower Female Genital Tract

GATA3 is a transcription factor critical for embryogenesis, development, and cell differentiation. Recent studies have suggested that GATA3 is a sensitive and relatively specific biomarker for urothelial and breast carcinomas, with most Müllerian carcinomas being negative. We investigated GATA3 expression in mesonephric/Wolffian remnants and tumors in the female genital tract. A western blot was performed to assess specificity for the GATA3 antibody. GATA3 immunohistochemistry was performed on 59 formalin-fixed paraffin-embedded mesonephric samples, including 17 mesonephric remnants (MR; 11 cervical and 6 fallopian tube), 15 mesonephric hyperplasias, 21 mesonephric carcinomas, and 6 female adnexal tumors of probable Wolffian origin. Thirty conventional endocervical adenocarcinomas (ENDO-CA), 9 gastric-type cervical adenocarcinomas, and 165 endometrial adenocarcinomas (EM-CA) were also evaluated. GATA3 nuclear intensity and extent of staining was evaluated. The western blot revealed GATA3 expression in seminal vesicle and cell lines derived from breast and urothelial carcinomas, but not in other cell lines including ovarian, cervical, and endometrial cancers. All cervical MRs and mesonephric hyperplasias, 5/6 (83%) fallopian tube MRs, and 20/21 (95%) mesonephric carcinomas were GATA3 positive, although with great variability in both intensity (weak to strong) and extent (1+ to 3+) of staining. Only 1/6 (17%) female adnexal tumors of probable Wolffian origin showed weak multifocal staining. One of 30 (3%) usual-type ENDO-CAs and 3/165 EM-CAs exhibited weak-moderate GATA3 immunoreactivity; all gastric-type cervical adenocarcinomas were negative. GATA3 is a highly sensitive and specific marker for mesonephric lesions in the lower genital tract; however, its utility in the upper genital tract may be more limited. In addition, GATA3 can aid in distinguishing lower genital mesonephric lesions from usual-type and gastric-type ENDO-CAs and uterine EM-CAs.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

The spectrum of cervical glandular neoplasia and issues in differential diagnosis

CONTEXT

Premalignant and malignant glandular lesions of the cervix are known to often cause diagnostic problems with a variety of benign (more common) as well as other malignant mimics, the latter setting often being represented by secondary involvement by endometrioid endometrial carcinoma especially in small samplings.

OBJECTIVE

To highlight key histologic features and immunohistochemical markers that may be helpful in the distinction of in situ endocervical carcinoma from benign glandular proliferations, and those that separate different subtypes of invasive endocervical carcinoma, as well as invasive carcinoma from other carcinomas secondarily involving the cervix and nonneoplastic proliferations of the cervix.

CONCLUSIONS

Clinical and morphologic features as well as immunohistochemistry results should be used in conjunction in the differential diagnosis of glandular proliferations of the cervix, as correct interpretation has major clinical consequences for the patient in most instances (especially benign versus malignant). Immunohistochemical markers should be used as part of a panel of antibodies, as exceptions may occur to the usual pattern of staining, and if used singly, they may mislead the pathologist to establish a wrong diagnosis.

Endometrial stromal sarcoma of the uterus presenting as pulmonary metastasis

Endometrial stromal sarcoma (ESS) is a rare uterine sarcoma. Compared with other uterine malignancies, it occurs at an earlier age (42-58 years) and about 10-25% of the patients are premenopausal. The tumours have an indolent growth, with a tendency for late recurrence. Metastases are rarely detected before the diagnosis of the primary lesion. We report a case of ESS with pulmonary metastasis as a prodromal manifestation.

A robust automated measure of average antibody staining in immunohistochemistry images

Identifying and scoring cancer markers plays a key role in oncology, helping to characterize the tumor and predict the clinical course of the disease. The current method for scoring immunohistochemistry (IHC) slides is labor intensive and has inherent issues of quantitation. Although multiple attempts have been made to automate IHC scoring in the past decade, a major limitation in these efforts has been the setting of the threshold for positive staining. In this report, we propose the use of an averaged threshold measure (ATM) score that allows for automatic threshold setting. The ATM is a single multiplicative measure that includes both the proportion and intensity scores. It can be readily automated to allow for large-scale processing, and it is applicable in situations in which individual cells are hard to distinguish. The ATM scoring method was validated by applying it to simulated images, to a sequence of images from the same tumor, and to tumors from different patient biopsies that showed a broad range of staining patterns. Comparison between the ATM score and manual scoring by an expert pathologist showed that both methods resulted in essentially identical scores when applied to these patient biopsies. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

A clinicopathological and immunohistochemical study of minimal deviation adenocarcinoma of the uterine cervix

OBJECTIVE

To investigate the clinical, pathological and immunohistochemical features of minimal deviation adenocarcinoma (MDA) of the uterine cervix by conducting a retrospective study of 25 cases consecutively treated in three institutes over a 10 years period.

METHODS

Of 25 cases with MDA, clinical features were retrospectively reviewed, gross and micro appearances of surgical specimens of 17 operative cases were observed. Ki67, SMA, p53, PCNA, Vimentin, CEA, ER, CA125 and PR were detected on tissues from MDA and 50 cases common adenocarcinomas of the uterine cervix (AUCs) (differentiation rank: high 16, moderate 20, low 14). Their expressions were assessed in paraffin sections using the immunohistochemistry method.

RESULTS

MDA accounted for only 1.2% of adenocarcinomas of the uterine cervix. The main clinical manifestations were vaginal profuse, watery or mucoid discharge and irregular bleeding. Signs were cervical hypertrophy or thickening. The gross appearance showed many similarities with common AUCs. Immunohistochemical results: the positive rates for p53 and Ki67 in >50% of the cell nuclei (Ki67/50(+)) were 88% and 64% in MDA respectively, significantly higher than common AUCs (38%, 18%, P<0.01), CA 125 was 18% in MDA, clearly lower than common AUCs (58%, P<0.01). There was no difference between MDA and common AUCs for CEA, PR, Vimentin, ER, PCNA and SMA (P>0.05). No significant difference was noticed among the high, moderate and low differentiation groups in common AUCs (P>0.05).

CONCLUSIONS

For early stage diagnoses, MDA should be considered when cervical hypertrophy is present in patients complaining of a vaginal profuse watery or mucoid discharge and irregular bleeding. Positive immunohistochemical staining for p53, Ki67/50(+) and negative for CA125 can assist diagnosis and discrimination.

A case of endometrial stromal sarcoma with synchronous bilateral adenocarcinoma of ovary

Endometrial stromal tumor is a rare mesenchymal uterine tumor. We report the case of a patient with endometrial stromal sarcoma and concomitant bilateral endometrioid adenocarcinoma of the ovary in the context of pelvic endometriosis. The patient underwent a complete cytoreduction including total hysterectomy and bilateral adnexectomy, pelvic lymphadenectomy, appendicectomy, infracolic omentectomy, and pelvic peritonectomy. This is the first report to our knowledge that describes a synchronous endometrial stromal sarcoma and bilateral endometrioid adenocarcinoma of the ovary.

New developments in endocervical glandular lesions

McCluggage W G (2012) Histopathology New developments in endocervical glandular lesions There is evidence that the prevalence of premalignant and malignant endocervical glandular lesions is increasing in real as well as in apparent terms. In this review, new developments and selected controversial aspects of endocervical glandular lesions are covered, concentrating mainly on premalignant and malignant lesions. The terminology of premalignant endocervical glandular lesions is discussed with a comparison of the World Health Organization classification and the cervical glandular intraepithelial neoplasia (CGIN) system, which is in widespread use in the United Kingdom. Primary cervical adenocarcinomas comprise a heterogeneous group of different morphological types, and while it is known that the majority of these are associated with high-risk human papillomavirus (HPV), it has become clear in recent years that most of the more uncommon morphological types are unassociated with HPV, although they may sometimes be p16-positive. A spectrum of benign, premalignant and malignant cervical glandular lesions exhibiting gastric differentiation is now recognized; these include type A tunnel clusters, typical and atypical lobular endocervical glandular hyperplasia, adenoma malignum and gastric-type adenocarcinoma. The latter is a recently described variant of primary cervical adenocarcinoma which has a different morphological appearance to the usual endocervical type and which is probably associated with different patterns of spread and a worse prognosis. There is accumulating evidence that 'early invasive' cervical adenocarcinomas have an excellent prognosis and are suitable for conservative management. Immunohistochemical markers of value in the distinction between a primary cervical and endometrial adenocarcinoma are discussed. While it is well known that a panel of markers comprising oestrogen receptor (ER), vimentin, p16 and monoclonal carcinoembryonic antigen (CEA) is useful, several major pitfalls are pointed out and this panel of markers is predominantly of value in 'low-grade' adenocarcinomas. A related group of lesions, including cervical ectopic prostatic tissue and vaginal tubulosquamous polyp, are probably derived from para-urethral Skene's glands and may be positive with prostatic markers. Recent developments in cervical neuroendocrine neoplasms are discussed, as these are associated not uncommonly with a premalignant or malignant endocervical glandular lesion.

Enhanced stability of microRNA expression facilitates classification of FFPE tumour samples exhibiting near total mRNA degradation

BACKGROUND

As degradation of formalin-fixed paraffin-embedded (FFPE) samples limits the ability to profile mRNA expression, we explored factors predicting the success of mRNA expression profiling of FFPE material and investigated an approach to overcome the limitation.

METHODS

Bladder (n=140, stored 3-8 years) and cervix (n=160, stored 8-23 years) carcinoma FFPE samples were hybridised to Affymetrix Exon 1.0ST arrays. Percentage detection above background (%DABG) measured technical success. Biological signal was assessed by distinguishing cervix squamous cell carcinoma (SCC) and adenocarcinoma (AC) using a gene signature. As miR-205 had been identified as a marker of SCC, precursor mir-205 was measured by Exon array and mature miR-205 by qRT-PCR. Genome-wide microRNA (miRNA) expression (Affymetrix miRNA v2.0 arrays) was compared in eight newer FFPE samples with biological signal and eight older samples without.

RESULTS

RNA quality controls (QCs) (e.g., RNA integrity (RIN) number) failed to predict profiling success, but sample age correlated with %DABG in bladder (R=-0.30, P<0.01) and cervix (R=-0.69, P<0.01). Biological signal was lost in older samples and neither a signature nor precursor mir-205 separated samples by histology. miR-205 qRT-PCR discriminated SCC from AC, validated by miRNA profiling (26-fold higher in SCC; P=1.10 × 10(-5)). Genome-wide miRNA (R=0.95) and small nucleolar RNA (R=0.97) expression correlated well in the eight newer vs older FFPE samples and better than mRNA expression (R=0.72).

CONCLUSION

Sample age is the best predictor of successful mRNA profiling of FFPE material, and miRNA profiling overcomes the limitation of age and copes well with older samples.

The Utility of p16INK4a and Ki-67 as a Conjunctive Tool in Uterine Cervical Lesions

Background

Immunohistochemical staining for p16INK4a and Ki-67 has been used to improve the accuracy in making a diagnosis of the uterine cervix cancer on biopsy. This study was conducted to examine the usefulness of these markers in the pathological diagnosis based on cervical biopsy.

Methods

We selected a consecutive series of 111 colposcopically directed cervical punch biopsies. Using these biopsy samples, we performed an immunohistochemical staining for p16INK4a and Ki-67 to establish a diagnosis. The slides were circulated among four pathologists in a sequential order: the hematoxylin and eosin (H&E) slide, H&E slide and p16INK4a-stained slide, and H&E slide, p16INK4a- and Ki-67-stained slides.

Results

The overall rates of the concordance in the first, the second, and the third diagnoses were 77.5%, 82.0%, and 82.0%, respectively. The rate of the concordance in the diagnosis of cervical intraepithelial neoplasm (CIN) 2/3 was increased from 62.2% to 73.0%. But there was a variability in the rate of the revision of the diagnosis between the pathologists. With the application of criteria for interpreting the expressions of p16INK4a and Ki-67, benign and CIN 1 lesions showed a p16INK4a expression score of 0 or 1. But CIN 2 and CIN 3 lesions showed a p16INK4a expression score of 2 and 3, respectively.

Conclusions

The immunostain for p16INK4a and Ki-67 might be useful in reducing an inter-observer variability. But criteria for interpreting both markers should be strictly applied.

Smear cytology findings of large cell neuroendocrine carcinoma of the uterine cervix

Large cell neuroendocrine carcinoma (LCNEC) of the uterine cervix is a rare tumor. Moreover, there are only three reports to date that have focused on the cytologic findings of cervical LCNEC. We report the case of a 59-year-old Japanese woman with cervical LCNEC combined with small cell carcinoma (SmCC). Cytologic specimens from the uterine cervix demonstrated large cells with coarse chromatin and prominent nucleoli. Frequent mitotic figures were also observed. Curettage of the uterine endometrium revealed an endometrioid adenocarcinoma with squamous differentiation; i.e., an adenoacanthoma. Histologic examination of surgically resected uterine cervical tissue revealed LCNEC with minor foci of SmCC. Neuroendocrine differentiation in LCNEC was confirmed by immunohistochemistry for synaptophysin and CD56. Cytotechnologists or pathologists need to consider a differential diagnosis of LCNEC while examining cervical cytologic specimens; therefore, it is important to correctly identify the cytologic characteristics of this tumor.

Exon-array profiling unlocks clinically and biologically relevant gene signatures from formalin-fixed paraffin-embedded tumour samples

Background:

Degradation and chemical modification of RNA in formalin-fixed paraffin-embedded (FFPE) samples hamper their use in expression profiling studies. This study aimed to show that useful information can be obtained by Exon-array profiling archival FFPE tumour samples.

Methods:

Nineteen cervical squamous cell carcinoma (SCC) and 9 adenocarcinoma (AC) FFPE samples (10–16-year-old) were profiled using Affymetrix Exon arrays. The gene signature derived was tested on a fresh-frozen non-small cell lung cancer (NSCLC) series. Exploration of biological networks involved gene set enrichment analysis (GSEA). Differential gene expression was confirmed using Quantigene, a multiplex bead-based alternative to qRT–PCR.

Results:

In all, 1062 genes were higher in SCC vs AC, and 155 genes higher in AC. The 1217-gene signature correctly separated 58 NSCLC into SCC and AC. A gene network centered on hepatic nuclear factor and GATA6 was identified in AC, suggesting a role in glandular cell differentiation of the cervix. Quantigene analysis of the top 26 differentially expressed genes correctly partitioned cervix samples as SCC or AC.

Conclusion:

FFPE samples can be profiled using Exon arrays to derive gene expression signatures that are sufficiently robust to be applied to independent data sets, identify novel biology and design assays for independent platform validation.

Ectopic prostatic tissue: histogenesis and histopathological characteristics

AIMS

To evaluate the histological and immunohistochemical characteristics of ectopic prostatic tissue.

METHODS AND RESULTS

We studied 20 cases of ectopic prostate. In 85% (17/20) of the cases, the ectopic prostatic tissue was located in the bladder; in the remaining cases, it was located in the urethra. In 60% of the cases (12/20), no significant inflammatory or reactive/reparative changes were identified in the adjacent tissue. Immunohistochemical stains for prostate-specific antigen, prostate-specific acid phosphatase, and prostein were positive in the glandular epithelial cells of all cases. Stains for 34βE12 and p63 confirmed the presence of basal cells in all cases. There was no overexpression of α-methylacyl-CoA racemase in any of the cases. There was cytoplasmic luminal staining for CD10 and cytoplasmic staining for cytokeratin 18 in acinar cells in all cases. In cases in which followup data were available, no patient was found to have residual or recurrent ectopic prostatic tissue and none developed prostatic adenocarcinoma.

CONCLUSIONS

Ectopic prostatic tissue is occasionally encountered in the lower urinary tract, most commonly in the bladder and urethra of males. Ectopic prostatic tissue has histological and immunohistochemical characteristics that are indistinguishable from those of normal prostatic tissue, and most likely represents the persistence of embryonic structures.

High-Grade Endometrial Carcinomas

High-grade endometrial carcinomas are a heterogeneous group of clinically aggressive tumors. They include FIGO grade 3 endometrioid carcinoma, serous carcinoma, clear cell carcinoma, undifferentiated carcinoma, and malignant mixed Müllerian tumor (MMMT). Epidemiologic, genetic, biologic prognostic and morphologic differences between these entities are striking in prototypic cases, yet substantial overlap exists and diagnostic criteria and therapeutic approaches that account for the group's diversity are currently insufficient. FIGO grade 3 endometrioid carcinoma demonstrates solid, trabecular or nested growth and may resemble poorly differentiated squamous cell carcinoma. Endometrioid glandular differentiation is usually focally present. Serous carcinoma usually displays papillary architecture but glandular and solid patterns may predominate. Tumor cells typically display diffuse and severe atypia. Clear cell carcinoma should be diagnosed by recognizing characteristic papillary or tubulocystic architecture with cuboidal tumor cells showing atypical but uniform nuclei. Cells with clear cytoplasm are frequently but not always present. On the other hand, clear cells may be encountered in endometrioid and serous carcinomas. Immunohistochemical stains for p53, p16, ER, PR, mib-1, hepatocyte nuclear factor 1β and pan-cytokeratin can be helpful in classifying these high-grade carcinomas. They should be used in concert with thorough morphologic examination, as part of a rational panel of markers and only in specific circumstances. Although these tumors may appear clinically and even morphologically similar, demographic and epidemiologic features as well as patterns of spread and treatment modalities differ.

Evaluation of p16INK4a immunohistochemical reactivity in endocervical glandular neoplasia

OBJECTIVE

To determine the expression of p16INK4a by immunohistochemistry in endocervical neoplasms.

METHODS

Forty-nine cases of endocervical glandular neoplasia were identified by record review. On histopathologic review of the original and new slides, 16 cases were identified as endocervical adenocarcinoma in situ (AIS), 31 were identified as invasive adenocarcinoma, and 2 had no remaining tumor identified. A representative paraffin block was selected from each case with tumor and sections cut from each block. One section from each case was stained with hematoxylin and eosin, 1 was processed for immunohistochemical study for p16INK4a, and 1 was a negative control. The nuclear immunoreactivity was graded positive, indeterminate, or negative.

RESULTS

Cases were classified AIS, adenocarcinoma, or no tumor. Of 16 cases of AIS, 15 (93.01%) cases were immunoreactive to p16INK4a; 1 case was negative. All cases of invasive adenocarcinoma, 31 of 31 cases (100%), were immunoreactive to p16INK4a.

CONCLUSIONS

p16INK4a reactivity can be used to help identify and assess in situ and invasive endocervical glandular neoplasms.

Diagnostic value and implications of vimentin expression in normal, reactive and neoplastic endocervical epithelium

AIMS

To assess vimentin immunoreactivity in normal, reactive and neoplastic endocervical epithelium, and compare the results with p16 protein, Ki-67 and bcl-2 expression.

METHODS

Sixty-two cervical biopsy specimens including normal endocervical epithelium, tubo-endometrioid metaplasia, adenocarcinoma in situ, stratified mucin producing intraepithelial lesions (SMILE), and invasive adenocarcinomas were stained immunohistochemically for vimentin and for p16 protein, Ki-67 and bcl-2. Twelve cases also included areas of high grade cervical intraepithelial neoplasia (CIN).

RESULTS

Normal endocervical epithelium usually showed subtle but distinct sub-nuclear and delicate lateral cell border vimentin expression while tubo-endometrioid metaplasia exhibited more diffuse cytoplasmic immunoreactivity. Usually adenocarcinoma in situ was completely negative and therefore vimentin staining sharply distinguished the benign and neoplastic epithelial elements. The SMILE lesions and high grade CIN were also vimentin negative in most cases. Most invasive adenocarcinomas were not stained but focal vimentin immunoreactivity was observed in 7/18 cases, and was restricted to small glands and infiltrating cell clusters at the deep (advancing) tumour margin.

CONCLUSIONS

Normal endocervical cells often exhibit vimentin staining, and this is increased in reactive and metaplastic situations, whereas adenocarcinoma in situ is usually completely negative. Therefore vimentin is a useful additional diagnostic marker in the assessment of problematic cervical glandular lesions. The localised re-expression of vimentin at the deep margin of some endocervical adenocarcinomas may be relevant to the process of tumour progression and invasion in these cases.

Minimal deviation adenocarcinoma of the uterine cervix

BACKGROUND

Precise preoperative diagnosis of minimal deviation adenocarcinoma (MDA) of the uterine cervix is often difficult because the histological features of MDA closely resemble those of normal cervical glands.

OBJECTIVE

To review the developments in the diagnosis and treatment of MDA over the past 35 years.

SEARCH STRATEGY

We performed a meta-analysis of all case reports published in the English and Chinese languages between 1975 and 2009 that included a histopathologic diagnosis of MDA. Pooled odds ratios and 95% CIs were calculated for comparisons and analyzed.

RESULTS

The histopathologic diagnosis of MDA remains difficult and is currently based on antigen detection by immunohistochemistry. Cytologic assessment and routine biopsy have low detection rates for MDA. Cross-sectional imaging techniques are helpful but a deep cervical biopsy or cervical conization is necessary for a definitive diagnosis. The mean survival is about 5 years for patients with stage I, 38.1 months for patients with stage II, 22.8 months for patients with stage III, and 5.4 months for patients with stage IV MDA.

CONCLUSION

Early diagnosis and treatment are key to improving prognosis and survival in patients with MDA.

Cyclin D1 immunoreactivity in normal endocervix and diagnostic value in reactive and neoplastic endocervical lesions

It may be difficult to distinguish reactive glandular lesions from adenocarcinoma in situ of the uterine cervix, and although several immunohistochemical markers have established value in this diagnostic setting, none is completely reliable. We have noted that neoplastic endocervical lesions often show loss of nuclear cyclin D1 expression in contrast to benign glandular cells. Therefore, we investigated cyclin D1 staining in a series of 64 cervical biopsy specimens including examples of normal and reactive endocervical epithelium, adenocarcinoma in situ, stratified mucin-producing intraepithelial lesions, and invasive adenocarcinoma. Thirteen specimens also included a component of high-grade cervical squamous intraepithelial neoplasia. Normal endocervical epithelium usually expressed cyclin D1, although staining was typically focal, and there was increased immunoreactivity in reactive and metaplastic glandular cells including tubo-endometrioid metaplasia. In contrast, most cases of adenocarcinoma in situ were completely negative and, therefore, cyclin D1 staining distinguished benign from neoplastic epithelial cells. Although focal cyclin D1 expression was observed in 5/19 cases of adenocarcinoma in situ, the staining was associated with more marked cytological atypia precluding confusion with a reactive process. The invasive adenocarcinomas were mainly negative for cyclin D1. However, focal staining was observed in 10/19 cases and was mainly restricted to cells at the deep tumor margin, or to small infiltrative glands and detached cell clusters within the stroma. In conclusion, cyclin D1 can be included within an immunohistochemical panel to aid in the distinction between reactive cervical glandular lesions and adenocarcinoma in situ. The localized distribution of staining within invasive lesions suggests that cyclin D1 up-regulation has a specific role during the progression of some endocervical adenocarcinomas.

The usefulness of immunohistochemistry in tissue microarrays of Human Papillomavirus negative adenocarcinoma of the uterine cervix

Background

The origin of adenocarcinomas presenting on the cervix uteri may be doubtful, i.e. whether it is of cervical or endometrial origin, due to the overlapping morphological features. In HPV negative samples, further tests may be needed to ascertain the nature of the tumours. We aimed to explore the use of immunohistochemistry profiles in tissue microarrays in archived samples of adenocarcinoma (ADC) of the cervix from Uganda that tested negative for HPV DNA.

Findings

Five commercially available antibodies were tested in tissue array sections immunostained utilizing the avidin-biotin (AB) technique. In 26 ADC samples, HPV was detected in 13, p16 in 15 (8 in HPV positive and 7 in HPV negative), CEA in 12, vimentin in 6, ER in 0, and PR in 2. Among the 13/25 HPV negative ADC samples, five were positive for CEA suggesting endocervical origin, and three were vimentin positive (one had a mucinous endocervical histological pattern and two were ADC, not otherwise specified, most likely of endometrial origin).

Conclusions

The immunoprofiles of ADC with the antibodies studied are rather nonspecific. By using immunohistochemistry in 13 HPV negative ADC, endocervical tumour origin was suspected in five CEA positive cases while two out of three vimentin positive samples were probably of endometrial origin, suggesting that CEA and vimentin may be valuable in distinguishing HPV negative cervical adenocarcinomas from endometrial adenocarcinomas.

Inverse p16 and p63 expression in small cell carcinoma and high-grade urothelial cell carcinoma of the urinary bladder

Small cell carcinoma (SmCC) of the urinary bladder is a rare, highly aggressive neoplasm. The diagnosis is usually made on morphologic grounds, with the help of immunohistochemistry to document neuroendocrine differentiation. However, neuroendocrine markers generally have low sensitivity, ranging between 30-70%. Recent studies have reported p16 over-expression in SmCC of the lung, suggesting that p16 immunohistochemistry may be useful in the diagnosis of bladder SmCC. This is the first study to analyze the usefulness of p16 in the distinction of small cell and high grade urothelial cell carcinoma (HG-UCC). Fourteen cases of SmCCs and sixteen cases of HG-UCC of the bladder were stained with p16, p63, cytokeratin 20 (CK20), cytokeratin 7 (CK7), chromogranin (Chr), synaptophysin (Syn), and CD56. P16 expression was significantly higher in SmCCs (92.8%) when compared to HG-UCCs (43.7%). P63 and CK20, on the other hand, were positive in the majority of HG-UCCs (81.3% and 50%, respectively), while only 14.3% of SmCCs showed focal immunoreactivity with CK20. The sensitivity of the traditional neuroendocrine markers was low, ranging between 28.6% (Chr) and 71.4% (CD56) in SmCCs. P16 positivity in the absence of p63 and CK20 is highly characteristic of SmCC, while p63 and CK20 positivity with or without p16 expression is typical of HG-UCC.

Merkel cell polyomavirus: a specific marker for Merkel cell carcinoma in histologically similar tumors

The recently described Merkel cell polyomavirus (MCPyV) is reportedly present in 50% to 80% of Merkel cell carcinomas (MCC). Although the virus has been shown to be absent from other cutaneous neoplasms, its association with malignancies that are histologically similar to MCC, specifically small cell carcinoma of the lung and other high-grade neuroendocrine tumors, has yet to be thoroughly investigated. To address this issue, we identified a set of 74 cases of visceral high-grade neuroendocrine tumors from a variety of anatomic sites, including 32 cases from the lung, 16 cases from the gastrointestinal tract, 20 cases from the female reproductive system, 3 cases from soft tissue, 2 cases from the head and neck region, and 1 case from the bladder. Using a set of primers optimized to detect MCPyV in formalin-fixed tissue, polymerase chain reaction (PCR)-based testing showed evidence of MCPyV DNA in only 1 of the 74 tumors; however, clinicopathologic review of the positive case (a neuroendocrine tumor of the small intestine) disclosed that the patient had a history of primary MCC of the buttock. PCR-based testing also showed no evidence of the related WU and KI polyomaviruses in the set of 74 cases. We conclude that, when evaluated by PCR-based testing, MCPyV is a specific marker for MCC that can be helpful in distinguishing cases of metastatic MCC from other high-grade neuroendocrine tumors. Our results also suggest that MCPyV does not have a role in the oncogenesis of visceral high-grade neuroendocrine tumors.