Tubo-Ovarian Transitional Cell Carcinoma and High-grade Serous Carcinoma Show Subtly Different Immunohistochemistry Profiles

Adenocarcinomas of the Gynecologic Tract Involving the Urinary Bladder: A Series of 16 Cases Potentially Mimicking Urothelial Malignancy

CONTEXT.—

There is limited literature describing gynecologic adenocarcinomas involving the urinary bladder and potential diagnostic pitfalls.

OBJECTIVE.—

To describe key features distinguishing metastatic (or extension of) gynecologic adenocarcinomas from urothelial carcinomas with glandular differentiation.

DESIGN.—

Retrospective review of surgical pathology cases of gynecologic adenocarcinomas involving the bladder from 2 different institutions, retrieved from surgical pathology archives, was performed. Morphologic features were recorded, along with immunohistochemistry results when available. Electronic medical records were reviewed for clinical and radiographic information.

RESULTS.—

Sixteen cases of gynecologic adenocarcinomas (9 endometrial endometrioid adenocarcinomas, 4 endometrial serous carcinomas, 2 high-grade tubo-ovarian serous carcinomas, and 1 cervical adenosquamous carcinoma) involving the bladder were identified. All included cases had mucosal involvement potentially mimicking primary bladder neoplasms, including 4 cases originally diagnosed as urinary carcinomas. Tumors expressed keratin 7 (12 of 13; 92%), PAX8 (11 of 12; 92%), estrogen receptor (11 of 15; 73%), p16 (8 of 11; 73%), progesterone receptor (8 of 14; 57%), GATA3 (5 of 12; 42%), and p63 (3 of 11; 27%); all tumors were negative for keratin 20 (0 of 12). Features supportive of Müllerian origin included prior history of gynecologic malignancy, lack of morphologic heterogeneity in nonendometrioid tumors, and immunophenotypic coexpression of PAX8 and estrogen receptor with absent GATA3. Potential pitfalls seen in a subset of cases included misleading radiologic and cystoscopic findings, replacement of the overlying urothelial mucosa by tumor mimicking precursor lesions, focal GATA3 and/or p63 positivity, and areas of squamous differentiation in tumors of endometrioid histology.

CONCLUSIONS.—

A combination of clinical history, certain morphologic features, and proper selection of immunohistochemical stains is key for the correct diagnosis of secondary gynecologic adenocarcinomas involving the urinary bladder.

Diagnostic roles of PAX8 immunohistochemistry in ovarian tumors

OBJECTIVE

This study aimed to elucidate the diagnostic roles of PAX8 immunohistochemistry in various ovarian tumors.

METHODS

We searched through the PubMed database and selected the eligible studies to perform the meta-analysis. The PAX8 immunohistochemical expression rates of various ovarian tumors, including primary and metastatic carcinomas, were analyzed. In addition, the subgroup analysis based on tumor behaviors was performed.

RESULTS

The PAX8 expression rates were 0.056 (95% confidence interval [CI] 0.008-0.307), 0.400 (95% CI 0.228-0.600), 0.741 (95% CI 0.578-0.857), and 0.738 (95% CI 0.666-0.799) in normal ovary and benign, borderline, and malignant ovarian tumors, respectively. The PAX8 expression rates of serous and transitional cell carcinomas were 0.937 (95% CI 0.882-0.967) and 0.918 (95% CI 0.841-0.959). In addition, the PAX8 expression rate of mucinous carcinomas was 0.393 (95% CI 0.285-0.512). However, metastatic carcinomas showed a significantly lower PAX8 expression rate than primary ovarian cancers (P < 0.001 in the meta-regression test). In cytologic specimens, PAX8 expression rates of serous and endometrioid carcinomas were 0.905 (95% CI 0.832-0.948) and 0.714 (95% CI 0.327-0.928), respectively.

CONCLUSION

PAX8 expression rate was significantly higher in serous ovarian tumors than in mucinous ovarian tumors. In addition, PAX8 expression rates were significantly higher in primary ovarian cancers than in metastatic carcinomas.

Molecular Histopathology for Establishing Diagnostic Method and Clinical Therapy for Ovarian Carcinoma

Ovarian carcinoma (OC) is considered the deadliest gynecological malignancy. It is typically diagnosed in the advanced stages of the disease, with metastatic sites widely disseminated within the abdominal cavity. OC treatment is challenging due to the high rate of disease recurrence, which is further complicated by acquired chemoresistance caused by the reversion of the pathological variant. Therefore, more effective treatments are still being sought. Histologically, OC is classified into serous, mucinous, endometrioid, clear cell, and transitional cell carcinomas and malignant Brenner tumor. Recent clinicopathological and molecular biological studies demonstrated that these subtypes differ in histogenesis and anti-tumor agent sensitivity. In Japan, the incidence rates of the histological types of OC, namely, serous carcinoma, mucinous carcinoma, endometrioid carcinoma, and clear cell adenocarcinoma, are 39%, 12%, 16%, and 23%, respectively. Serous carcinoma is classified as high or low grade, with the former accounting for the overwhelming majority. In this study, the molecular pathological classification of OC has been described based on the characteristics of the two types of OC, types 1 and 2. Compared with Europe and the United States, Japan has a higher prevalence of type 1 OC and a lower prevalence of type 2 OC. The prevalence of each type of OC varies by race. It has been elucidated that the prevalence rate of each type of ovarian cancer in Asian countries is similar to that in Japan. Thus, OC is a heterogeneous disease. Furthermore, OC has been attributed to molecular biological mechanisms that vary among tissue subtypes. Therefore, it is necessary to conduct treatment based on accurate diagnoses of each tissue type and establish an optimal treatment strategy, and now is the transition period.

Proteomic analysis of transitional cell carcinoma-like variant of tubo-ovarian high-grade serous carcinoma

The current World Health Organization classification does not distinguish transitional cell carcinoma of the ovary (TCC) from conventional tubo-ovarian high-grade serous carcinoma (HGSC), despite evidence suggesting improved prognosis for patients with TCC; instead, it is considered a morphologic variant of HGSC. The immunohistochemical (IHC) markers applied to date do not distinguish between TCC and HGSC. Therefore, we sought to compare the proteomic profiles of TCC and conventional HGSC to identify proteins enriched in TCC. Prognostic biomarkers in HGSC have proven to be elusive, and our aim was to identify biomarkers of TCC as a way of reliably and reproducibly identifying patients with a favorable prognosis and better response to chemotherapy compared with those with conventional HGSC. Quantitative global proteome analysis was performed on archival material of 12 cases of TCC and 16 cases of HGSC using SP3 (single-pot, solid phase-enhanced, sample preparation)-Clinical Tissue Proteomics, a recently described protocol for full-proteome analysis from formalin-fixed paraffin-embedded tissues. We identified 430 proteins that were significantly enriched in TCC over HGSC. Unsupervised co-clustering perfectly distinguished TCC from HGSC based on protein expression. Pathway analysis showed that proteins associated with cell death, necrosis, and apoptosis were highly expressed in TCCs, whereas proteins associated with DNA homologous recombination, cell mitosis, proliferation and survival, and cell cycle progression pathways had reduced expression. From the proteomic analysis, three potential biomarkers for TCC were identified, claudin-4 (CLDN4), ubiquitin carboxyl-terminal esterase L1 (UCHL1), and minichromosome maintenance protein 7 (MCM7), and tested by IHC analysis on tissue microarrays. In agreement with the proteomic analysis, IHC expression of those proteins was stronger in TCC than in HGSC (p < 0.0001). Using global proteomic analysis, we are able to distinguish TCC from conventional HGSC. Follow-up studies will be necessary to confirm that these molecular and morphologic differences are clinically significant.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

A Comprehensive Review of Ovarian Serous Carcinoma

Although ovarian serous carcinoma is a well-studied human gynecologic malignancy, this high-grade tumor remains fatal. The main purpose of this review is to summarize the accumulated evidence on serous malignant tumors and to clarify the unresolved issues. We discuss the 8 dichotomies of serous carcinoma: high grade versus low grade, ovarian versus extraovarian primary, extrauterine versus uterine primary, sporadic versus hereditary, orthodox versus alternative histology, p53 overexpression versus complete absence of immunophenotype, TP53-mutated versus intact precursor, and therapy responsive versus refractory. In addition, we summarize the molecular classification of high-grade serous carcinoma. This review would lead readers to rapid and parallel developments in understanding high-grade serous carcinoma.

[Pitfalls and common problems in the differential diagnosis of epithelial ovarian tumors]

Epithelial ovarian tumors may cause various diagnostic problems of practical relevance. For the distinction between cystadenomas and borderline tumors/atypically proliferative tumors, a minimum extent of 10% of the atypical epithelial proliferation has been suggested by the WHO. The micropapillary variant of serous borderline tumors is more frequently associated with invasive growth and extraovarian lesions. Extraovarian lesions of borderline tumors are relevant for prognosis and cause a higher stage; their classification is crucial. Traditionally, they were classified into noninvasive and invasive implants based on their morphology. Based on the 2014 WHO classification, invasive lesions should be designated as low-grade serous carcinomas whereas only noninvasive lesions are considered implants. The most frequent invasive growth pattern in low-grade serous carcinomas consists of haphazardly arranged tumor cell nests and small papillae in clefts, whereas mucinous and endometrioid carcinomas mainly show a confluent glandular pattern with maze-like and cribriform structures. For metastatic mucinous tumors a nodular growth pattern is characteristic; ruling them out requires clinical information including imaging and immunohistochemistry. Differential diagnosis between low-grade and high-grade serous carcinoma is based on the degree of nuclear polymorphism and mitotic count. The seromucinous tumor category replaces the endocervical subtype of mucinous tumors and resembles histologically, biologically, and on the molecular level serous and endometrioid tumors. Endometrioid tumors with fibromatous stroma need to be distinguished from tumors with Sertoli cell differentiation and well-differentiated neuroendocrine tumors. For differential diagnosis of epithelial ovarian tumors, in particular carcinomas, a panel of antibodies for immunohistochemistry is very useful under consideration of histomorphology.

High-grade serous ovarian carcinoma with mucinous differentiation: report of a rare and unique case suggesting transition from the "SET" feature of high-grade serous carcinoma to the "STEM" feature

BACKGROUND

High-grade serous carcinoma, a representative high-grade ovarian carcinoma, is believed to be closely associated with a TP53 mutation. Recently, this category of ovarian carcinoma has gained increasing attention owing to the recognition of morphological varieties of TP53-mutated high-grade ovarian carcinoma. Herein, we report the case of a patient with high-grade serous carcinoma with mucinous differentiation.

CASE PRESENTATION

A 59-year-old postmenopausal woman was referred to the gynecologist because of abnormal vaginal bleeding. The radiological assessment revealed an intrapelvic multicystic mass, which was interpreted as an early right ovarian cancer and then removed by radical surgery. Histologically, the cancer cells were found in the bilateral ovaries and para-aortic lymph nodes. The cancer cells showed high-grade nuclear atypia and various morphologies, including the solid, pseudo-endometrioid, transitional cell-like (SET) pattern, and mucin-producing patterns. Benign and/or borderline mucin-producing epithelium, serous tubal intraepithelial carcinoma, and endometriosis-related lesions were not observed. In immunohistochemistry analyses, the cancer cells were diffuse positive for p53; block positive for p16; partial positive for WT1, ER, PgR, CDX2 and PAX8; and negative for p40, p63, GATA3, Napsin A, and vimentin. The Ki-67 labeling index of the cancer cells was 60-80%. Direct sequencing revealed that the cancer cells contained a missense mutation (c.730G>A) in the TP53 gene.

CONCLUSION

Mucinous differentiation in high-grade serous carcinoma is a rare and unique ovarian tumor phenotype and it mimics the phenotypes of mucinous or seromucinous carcinoma. To avoid the misdiagnosis, extensive histological and immunohistochemical analyses should be performed when pathologists encounter high-grade mucin-producing ovarian carcinoma. The present case shows that the unusual histological characteristic of high-grade serous carcinoma, the "SET" feature, could be extended to the solid, transitional, endometrioid and mucinous-like (STEM) feature.