Müllerian inhibiting substance, alpha-inhibin, and CD99 expression in sex cord-stromal tumors and endometrioid ovarian carcinomas resembling sex cord-stromal tumors

Pathological discrimination between luteinized thecoma associated with sclerosing peritonitis and thecoma

BACKGROUND

Similarities between luteinized thecoma associated with sclerosing peritonitis (LTSP) and thecoma, cause difficulty in clinical differential diagnoses. To improve the situation, we selected 10 specified molecular pathological markers that are frequently used in clinical pathology of ovarian sex cord-stromal tumors to determine whether they exert a discriminatory effect.

METHODS

Applying immunohistochemistry, we analyzed the expression of alpha-1,6-mannosylglycoprotein 6-beta-n-acetylglucosaminyltransferase B (MGAT5B), nuclear receptor coactivator 3 (NCOA3), proliferation marker protein Ki-67 (MKI67), estrogen receptor, progesterone receptor, Vimentin, receptor tyrosine-protein kinase erbB-2, Catenin beta-1 (β-Catenin), CD99 antigen (CD99) and Wilms tumor protein (WT1) in 102 cases of diseases containing 11 LTSP and 91 thecoma. Whole-exome sequencing and fluorescence in situ hybridization were used to examine the MGAT5B-NCOA3 fusion gene in LTSP. Statistical analysis was performed using t test, one-way analysis of variance test, and post hoc test.

RESULTS

Six significant markers were verified for the discrimination between LTSP and thecoma, containing 4 upregulating indicators MGAT5B, NCOA3, MKI67, β-Catenin, and 2 downregulating markers CD99 and WT1 in luteinized cells. In addition, the MGAT5B-NCOA3 fusion gene was identified in LTSP for the first time with significantly rich expression compared to thecoma.

CONCLUSIONS

We verified 6 significant molecular pathological markers containing MGAT5B, NCOA3, MKI67, β-Catenin, CD99, and WT1 and identified MGAT5B-NCOA3 fusion gene in LTSP; this work will help clinicians to discriminate between medical conditions and treat patients accurately.

A Case of Endometrial Carcinosarcoma Containing Sertoliform Endometrioid Carcinoma Component

Carcinosarcomas (CSs) of the endometrium have admixture of malignant epithelial and mesenchymal components. The carcinomatous component exhibit endometrioid, serous, or clear cell differentiation, or are undifferentiated. CSs are considered homologous or heterologous according to the type of sarcomatous component. Sertoliform endometrioid carcinomas (SECs) of the endometrium which comprise a rare subtype of endometrial cancer, typically occur in the ovary. SECs as a carcinomatous component of CS of the endometrium have not been reported. Here, we report an endometrial carcinosarcoma that contains an SEC component. An 88-year-old female presented to a clinic with atypical genital bleeding. She was referred to our hospital and underwent total hysterectomy, bilateral adnexectomy and partial omentectomy due to endometrial carcinoma. Gross examination revealed a polypoid mass in the uterine cavity with massive myometrial invasion. Histologically, the tumor was a high-grade endometrioid carcinoma. In addition to an ordinary conventional endometrioid carcinoma, approximately 30% of the area exhibited sex cord-like pattern and contained small hollow tubules, anastomosing cords and trabeculae, and tightly packed nests. Immunohistochemically, the SEC component showed diffuse p53 staining. Sex cord-like area, especially the solid area, showed positive staining for EMA, vimentin, α-inhibin, CD99, calretinin, p53, CD56, synaptophysin, and chromogranin A, which is a staining pattern similar to that previously reported SEC of the endometrium. Diminished membranous and positive cytoplasmic staining for β-catenin was observed. This is the first case report of an endometrial carcinosarcoma containing an SEC component. SECs of the endometrium might exhibit sex cord-like differentiation in contrast to SECs of the ovary, which do not exhibit sex cord differentiation.

Anti-Müllerian Hormone Expression in Endometrial Cancer Tissue

Anti-Müllerian hormone (AMH) is a commonly known factor secreted by Sertoli cells, responsible for regression of the Müllerian ducts in male fetuses. AMH has also other functions in humans. In vivo and in vitro studies have shown that AMH inhibits cell cycle and induces apoptosis in cancers with AMH receptors. The aim of the study was to assess whether the tissue of pre-cancerous states of endometrium (PCS) and various histopathologic types of endometrial cancer (EC) exhibit the presence of AMH. We aimed to investigate whether the potential presence of the protein concerns menopausal women or those regularly menstruating, and whether is related to cancers with a good or a bad prognosis, as well as what other factors may influence AMH expression. The undertaken analysis was carried out on tissues retrieved from 232 women who underwent surgical treatment for PCS and EC. Tissues were prepared for immunohistochemical assessment with the use of a tissue microarrays method. AMH expression was confirmed in 23 patients with well differentiated endometrioid adenocarcinoma (G1), moderately differentiated endometrioid adenocarcinoma (G2), clear cell carcinoma (CCA) and nonatypical hyperplasia. AMH was not found in EC tissues in regularly menstruating women. An appropriately long mean period of breastfeeding in line with a prolonged period of hormonal activity had a positive effect on AMH expression. Our results may suggest that AMH is a factor which protects the organism against cancer, and should be further investigated as a potential prognosis marker and a therapeutic agent.

Ovarian sex cord-stromal tumours: an update in recent molecular advances

Sex cord-stromal tumours (SCSTs) consist of a heterogeneous group of neoplasms with diverse clinicopathological features and biological behaviour. They often present as a diagnostic challenge as they have varied and occasionally overlapping histomorphology and some may even mimic non-SCSTs. An accurate diagnosis is important for therapeutic and prognostic purposes. The use of a panel of immunohistochemical markers which are sensitive and specific for sex cord-stromal differentiation such as α-inhibin, calretinin, SF-1 and FOXL2, may be helpful in confirming the cellular lineage of these tumours, but is of limited utility in distinguishing between the different tumour types within this category. Additionally, the development of new therapeutic strategies in patients with SCSTs is also hampered by the infrequent occurrence of these neoplasms. Recent molecular analyses of some SCSTs has led to the discovery of novel molecular events, which may have important diagnostic, prognostic and therapeutic implications. The salient pathological features, management issues and recently described genetic aberrations in adult and juvenile granulosa cell tumours as well as Sertoli-Leydig cell tumours are discussed in this review, with particular emphasis on the clinical significance of FOXL2 and DICER1 mutations. An in-depth understanding of the molecular pathogenesis underlying SCSTs may aid in improving tumour classification and disease prognostication and also potentially lead to the discovery of more effective treatment strategies.

Endometriosis-associated ovarian neoplasia

This article reviews the most relevant pathological and molecular features of ovarian tumours that are associated with endometriosis. Endometriosis is a common condition, affecting 5-15% of all women, and it has been estimated that 0.5-1% of cases are complicated by neoplasia. The most common malignant tumours in this setting are endometrioid adenocarcinoma and clear cell adenocarcinoma, each accounting for approximately 10% of ovarian carcinomas in Western countries. A minority of cases are associated with Lynch syndrome. These carcinomas are often confined to the ovaries at presentation in which case they have relatively favourable outcomes. However, high-stage tumours, particularly clear cell carcinomas, generally have a poor prognosis and this partly reflects relative resistance to current treatment. Histological diagnosis is straightforward in the majority of cases but some variants, for example endometrioid carcinomas with sex cord-like appearances or oxyphil cells, may create diagnostic difficulty. Similarly, clear cell carcinomas can show a range of architectural and cytological patterns that overlap with other tumours, both primary and metastatic, involving the ovaries. Endometriosis-associated borderline tumours are less common, and they often show mixed patterns of differentiation (seromucinous tumours). Atypical endometriosis may represent an intermediate step in neoplastic progression and some of these lesions demonstrate immunohistological and molecular alterations similar to those observed in endometriosis-related tumours. ARID1A mutations are relatively common in all of these tumours, but each has additional characteristic molecular alterations which are likely to be of increasing clinical relevance as targeted therapies are developed. Less is known of the pathogenesis of rarer endometriosis-associated ovarian tumours including endometrioid stromal sarcoma, mesodermal (Müllerian) adenosarcoma, and carcinosarcoma. This article also briefly reviews the issue of synchronous endometrioid carcinomas of the endometrium and the ovary, including the most recent developments on pathogenesis.

Potential therapeutic applications of human anti-Müllerian hormone (AMH) analogues in reproductive medicine

Members of the transforming growth factor-beta (TGF-beta) superfamily are key regulators of various physiological processes. Anti-Müllerian hormone (AMH) which is also commonly known as Müllerian-inhibiting substance (MIS) is a member of the TGF-beta superfamily and an important regulator of reproductive organ differentiation and ovarian follicular development. While AMH has been used for diagnostic purposes as a biomarker for over 15 years, new potential therapeutic applications of recombinant human AMH analogues are now emerging as pharmacologic agents in reproductive medicine. Therapeutic uses of AMH in gonadal tissue may provide a unique opportunity to address a broad range of reproductive themes, like contraception, ovulation induction, onset of menopause, and fertility preservation, as well as specific disease conditions, such as polycystic ovarian syndrome (PCOS) and cancers of the reproductive tract. This review explores the most promising therapeutic applications for a novel class of drugs known as AMH analogues with agonist and antagonist functions.

Retiform Sertoli-Leydig Cell Tumor in a 38-Year-Old Woman: A Case Report, Retrospective Review, and Review of Current Literature

Ovarian sex cord-stromal tumors arise from the stromal cells that surround and support the oocytes. Sertoli-Leydig cell tumors belong to this category of ovarian neoplasms. We present the case of a 38-year-old woman who was found to have a right ovarian mass. The mass was resected and diagnosed as Stage I Sertoli-Leydig cell tumor, retiform variant, following histopathologic and immunohistochemical examination. This case is unusual given the rarity of the retiform variant of Sertoli-Leydig cell tumor and the atypically older age of 38 years at presentation.

The Application of Immunohistochemical Biomarkers in Urologic Surgical Pathology

Context

Tumors of the genitourinary tract can be diagnostically challenging, particularly in core biopsies and cystoscopic biopsies with limited material. Immunohistochemistry is a valuable tool to use when morphology alone is insufficient for diagnosis.

Objectives

To review tumors and benign lesions of the kidney, urinary bladder, prostate gland, testis, and paratesticular structures with an emphasis on difficult differential diagnoses, as well as staining patterns in normal tissue. Recommended immunohistochemical stain panels are discussed that can assist in the diagnostic workup.

Data Sources

Review of current literature.

Conclusions

Immunohistochemistry is a valuable tool, assisting in the diagnosis of problematic tumors and benign lesions of the genitourinary tract.

Precocious puberty secondary to a mixed germ cell-sex cord-stromal tumor associated with an ovarian yolk sac tumor: a case report

INTRODUCTION

Ovarian tumors are the least common cause of sexual precocity in girls. Mixed germ cell-sex cord-stromal tumors associated with a yolk sac tumor of the ovary are rare neoplasms, of which only a small number of well-documented cases have been described so far. Here, we report precocious puberty in a four-year-old Egyptian girl caused by a mixed germ cell-sex cord-stromal tumor associated with a yolk sac tumor of the ovary.

CASE PRESENTATION

A four-year-old Egyptian girl was referred to our pediatric endocrinology unit for evaluation of bilateral breast budding, pubic hair and vaginal bleeding. On examination, we found that her breast enlargement and pubic hair were compatible with Tanner III. A thorough workup revealed a large mass in her right ovary. Magnetic resonance imaging ofher brain showed that her pituitary gland was normal. A hormonal assay revealed high levels of estradiol, 280 to 375pmol/L; progesterone, 5.3 nmol/L; testosterone 38.9 pg/mL; and androstenedione, 4.1 ng/mL. Her basal and stimulated levels of luteinizing hormone and follicle-stimulating hormone were low. Tumor markers levels were high, with a total inhibin of 1,069U/L and an alpha-fetoprotein of 987 μg/L. Her chromosomes were normal (46XX). Our patient underwent an explorative laparotomy and a solid tumor localized to her right ovary was identified. A right salpingo-oophorectomy was performed and the histopathological diagnosis was a mixed germ cell-sex cord-stromal tumorwith a yolk sac tumor of the ovary. Postoperatively, she was started on treatment with chemotherapy. Our patient is doing well without evidence of tumor recurrence or metastasis during eight months of postoperative follow-up.

CONCLUSION

Although a mixed germ cell-sex cord-stromal tumor associated with a yolk sac tumor of the ovary is a rare occurrence, it should be considered in the differential diagnosis for a prepubescent girl with an abdominal mass and precocious puberty.

Ovarian carcinoma pathology and genetics: recent advances

In this review we summarize recent advances in the histopathological diagnostic criteria and molecular pathology of the main subtypes of ovarian surface epithelial carcinoma. These advances have greatly improved our understanding of the biology of ovarian carcinoma and are also relevant to patient management. With progress toward subtype-specific treatment of ovarian carcinoma, accurate, reproducible histopathological diagnosis of these subtypes by practicing pathologists is increasingly important.

Frequent expression of CD99 in anaplastic large cell lymphoma: a clinicopathologic and immunohistochemical study of 160 cases

Originally described as a diagnostically useful marker for Ewing sarcoma, CD99 immunoreactivity has also been documented in a variety of other tumors, including hematopoietic neoplasms. By using conventional paraffin immunoperoxidase staining and tissue microarrays, we retrospectively investigated CD99 expression in a series of 160 anaplastic large cell lymphoma (ALCL) cases. Of the 160 cases, 103 (64.4%) were positive for CD99. The distribution of CD99 positivity was similar for nodal (66/103 [64.1%]), extranodal, (21/32 [66%]), and primary cutaneous lesions (16/25 [64%]). CD99 expression was present in 96 (64.4%) of 149 of the common type, 4 (80%) of 5 of the small cell variant, and 3 (50%) of 6 of the lymphohistiocytic variant cases. CD99 expression was slightly more frequent in anaplastic large cell lymphoma kinase (ALK)+ cases compared with ALK- cases (43/54 [80%] vs 44/81 [54%]). With 2 exceptions, ALK+ ALCL was seen only in patients younger than 41 years. We conclude that CD99 is frequently expressed in ALCL, with a slightly increased frequency in the younger age ALK+ cases. Nodal and extranodal ALCL should be considered in the differential diagnosis when a CD99+ neoplasm is encountered.

Calretinin: diagnostic utility in the female genital tract

The utility of calretinin was first described in the diagnosis of mesothelioma. In the female genital tract, calretinin was initially reported in Wolffian remnants and related lesions and later used in the diagnosis of sex cord stromal tumors of the ovary, endometrial stromal tumors with sex cord-like differentiation, and uterine tumors resembling sex cord tumors of the ovary. This review discusses calretinin expression in normal tissues of the female genital tract and highlights its potential utility in the diagnosis of these subsets of neoplasms with emphasis to tumors that may constitute a problem in their differential diagnosis. In particular, the limited utility of calretinin in the diagnosis of sex cord stromal tumors of the ovary, in the differential diagnosis between mesothelioma and serous tumors involving the ovary and/or peritoneum, and in the differential diagnosis between Wolffian lesions and endometrial carcinoma are addressed.

WT1 expression in endometrioid ovarian carcinoma with and without associated endometriosis

AIMS

To determine how frequently endometrioid ovarian carcinomas (EOC) express WT1 protein, and to correlate the results with the presence of endometriosis and p53 immunoreactivity.

METHODS

Forty-one grade 1-2 EOC were stained immunohistochemically for WT1 and p53 proteins. Twenty-one tumours were associated with endometriosis and 20 cases lacked such an association. WT1 expression in the tumour cell nuclei and/or cytoplasm was recorded. Nuclear p53 staining was assessed as diffuse (>50% cells positive), focal, or negative.

RESULTS

Four of the 20 (20%) tumours in the endometriosis negative group showed nuclear WT1 staining, while none of the endometriosis-associated EOC was positive (p < 0.05). Two of the immunoreactive cases exhibited sertoliform/sex cord-like patterns. Focal cytoplasmic WT1 labelling was present in seven EOC, three of which showed sertoliform, spindle cell or corded and hyaline patterns. There was no correlation between WT1 expression and p53 immunoreactivity.

CONCLUSIONS

Nuclear WT1 expression is present in a minority of EOC and this should be considered if immunohistochemistry is used as an adjunct in sub-typing ovarian carcinomas. The negative correlation of WT1 staining with endometriosis supports the possibility that some EOC, including unusual histological variants, arise from the ovarian surface epithelium. Further studies of EOC should document any association with endometriosis.

Molecular genetic evidence supporting the neoplastic nature of the Leydig cell component of ovarian Sertoli-Leydig cell tumors

Sertoli-Leydig cell tumors (SLCT) comprise less than 1% of ovarian tumors. The nature of the Leydig cells has been a subject of controversy and it is unclear whether they are clonally related to the neoplasm or instead proliferate as a non-neoplastic response to the Sertoli-cell component. Twelve ovarian SLCT were identified and hematoxylin and eosin and unstained sections were prepared from formalin-fixed, paraffin-embedded tissue blocks. Tissue samples were microdissected from normal tissue, the Sertoli cell component, and the Leydig cell tumor component using the laser capture microdissection method. If present, tissue was also obtained from any heterologous component. Genomic DNA was extracted from the samples and polymerase chain reaction was used to amplify polymorphic sites at 5 loci: D16S402, TP53, IFNA, D17S855, and D11S1318. X-chromosome inactivation (HUMARA) analysis was also performed. LOH and/or nonrandom X-chromosome inactivation was observed in at least 1 of the 6 amplified loci in the Leydig cell component of 10 of the 12 tumors. LOH and nonrandom X-chromosome inactivation patterns of the Sertoli cell component and Leydig cell component were compared. Concordant allelic loss and/or matching X-chromosome inactivation patterns were observed in 8 (67%) of the 12 tumors. In 7 of these tumors similar LOH or X-chromosome inactivation was observed at 1 site. In 1 tumor similar LOH and/or X-chromosome inactivation was observed at 2 sites. Three tumors had heterologous components. The heterologous components similarly shared LOH/X-chromosome inactivation with the Sertoli cell components at 1 site in 1 case and 2 sites in 2 cases. These data suggest that, at least in some cases, the Leydig cell component of SLCT is neoplastic rather than reactive in nature, and shares a common clonal origin with the coexisting Sertoli cell component. Similarly, the heterologous components, when present, appear to share clonal origin with the Sertoli cell components.

CD10 Expression in Pure Stromal and Sex Cord-Stromal Tumors of the Ovary

CD10 has been recently advocated as a good immunohistochemical marker for endometrial stromal tumors. Metastatic endometrial stromal tumors to the ovary and primary endometrioid stromal sarcomas may show overlapping histological features with pure stromal and sex cord-stromal tumors (SCSTs). We investigated CD10 expression in a large series of pure stromal and SCSTs of the ovary to ascertain whether CD10 may aid in this differential diagnosis. Archival material from 11 fibromas, 10 thecomas, 10 sclerosing stromal tumors (SSTs), 10 adult granulosa cell tumors (AGCTs), 4 luteinized AGCTs, 9 juvenile granulosa cell tumors (JGCTs), 9 Sertoli cell tumors, 9 Sertoli-Leydig cell tumors, 11 sex cord tumors with annular tubules, 10 steroid cell tumors (StCTs), and 8 fibrosarcomas of the ovary were immunostained for CD10. The percentage of cells stained (<5%, 5%-39%, 40%-75%, and >75%) and intensity of staining (1+, 2+, 3+) were evaluated. CD10 was expressed in 7 of 10 thecomas (4 with 5%-75% and mostly 1+), 9 of 10 SSTs (7 with 5%-39% + cells, mostly 1+), 9 of 10 AGCTs (<5%-39%, four 1+, five 2+), 1 of 4 luteinized AGCTs (<5% and 1+), 8 of 9 JGCTs (mostly <5% to 39% and +1), 4 of 9 Sertoli cell tumors (either focal or >75% with variable intensity), 4 of 9 Sertoli-Leydig cell tumors (mostly <10% with variable staining), with the Leydig cells being positive in only 1 tumor (1+ and <5%), and 7 of 10 StCTs (4 tumors with more than 75% + cells, from 1+ to 3+). All fibromas, all but 1 fibrosarcoma (<5% and 1+), and all sex cord tumors with annular tubules were CD10 negative. CD10 expression was frequently seen in StCTs, SSTs, and thecomas of the ovary, although the latter 2 categories usually showed only faint immunoreactivity. In conclusion the frequency and intensity of CD10 immunoreactivity in pure stromal and sex cord-stromal ovarian tumors are low and contrast with the typical strong and diffuse immunostaining seen in endometrial stromal tumors; however, faint CD10 positivity is consistent with the diagnosis of ovarian SCST. Steroid cell tumors are often positive for CD10, but these tumors do not pose problems in differential diagnosis with endometrial stromal tumors. CD10 may play a useful role in aiding the differential between endometrial stromal tumors in the ovary and SCST and stromal tumors.

Ovarian spindle cell lesions: a review with emphasis on recent developments and differential diagnosis

Ovarian lesions composed of spindle cells comprise a heterogeneous group; most are neoplastic but several non-neoplastic conditions are also composed of spindle cells. This review discusses the main differential diagnoses of an ovarian spindle cell lesion, especially concentrating on the recent literature. The majority of ovarian spindle cell lesions fall into the broad category of fibromatous neoplasms whereas others in the sex cord-stromal group may also be composed of spindle cells, including thecomas, granulosa, and Sertoli-Leydig cell tumors and rarer neoplasms, such as sclerosing stromal tumor and signet-ring stromal tumor. In the recent past there have been several major contributions on various aspects of ovarian spindle cell lesions, including cellular and mitotically active cellular fibromatous lesions, smooth muscle neoplasms, and metastatic gastrointestinal stromal tumors. Other mesenchymal or epithelial tumors and mixed epithelial and mesenchymal neoplasms may also enter into the differential diagnosis of an ovarian spindle cell lesion. Several non-neoplastic lesions may be composed of spindle cells, including massive edema, ovarian fibromatosis, stromal hyperplasia, and stromal hyperthecosis. Morphology remains the mainstay in diagnosis but immunohistochemistry may be invaluable in certain circumstances, one example being the identification of a metastatic gastrointestinal stromal tumor within the ovary.

Diagnostic Utility of WT1 Immunostaining in Ovarian Sertoli Cell Tumor

WT1, the Wilms tumor gene product, can be expressed in various tumors from different anatomic sites, including some types of ovarian tumors. Regarding the latter, most studies have focused on surface epithelial-stromal tumors in which serous carcinomas are usually positive and endometrioid carcinomas are negative. Very few studies have specifically investigated this marker in ovarian sex cord-stromal tumors; however, limited data in the literature suggest that WT1 may be frequently expressed in sex cord-stromal tumors. As pure Sertoli cell tumor can be in the histologic differential diagnosis of endometrioid tumors (particularly borderline tumor and carcinoma) and carcinoid, immunostaining for WT1 might be of diagnostic value. Immunohistochemical staining for WT1 was performed in 108 ovarian tumors: pure Sertoli cell tumor (n=26), endometrioid borderline tumor (n=25), classic well-differentiated endometrioid carcinoma (n=23), sertoliform endometrioid carcinoma (n=12), and carcinoid (n=22). Additionally, inhibin and calretinin immunostaining were performed in all cases of Sertoli cell tumor for purposes of comparing expression with WT1. Extent of immunostaining was scored on a 0 to 4+ semiquantitative scale, and immunohistochemical composite scores based on a combination of extent and intensity of immunostaining were calculated in positive cases (possible range, 1 to 12). Nuclear expression of WT1 was present in 96% of Sertoli cell tumors, 16% of endometrioid borderline tumors, 13% of classic well-differentiated endometrioid carcinomas, 25% of sertoliform endometrioid carcinomas, and 0% of carcinoids. In Sertoli cell tumors, expression was diffuse (>50% of positive cells) in all positive cases. When positive in the non-Sertoli cell tumors, the extent of expression tended to be focal to patchy (50% or less positive cells). In Sertoli cell tumors, inhibin and calretinin were expressed in 96% and 54% of cases, respectively. The extent of expression of inhibin tended to be diffuse, similar to WT1; however, the extent of immunostaining for calretinin tended to be focal to patchy. The immunohistochemical composite scores for WT1, inhibin, and calretinin were 11.2, 7.6, and 4.8, respectively. Coordinate patterns for the extent of expression of WT1, inhibin, and calretinin in pure Sertoli cell tumor showed that all 3 markers were positive in 54% of cases; however, 42% were positive for WT1 and inhibin but negative for calretinin. In cases positive for both WT1 and inhibin, expression of both markers was diffuse in 84% of cases, but WT1 was diffuse while inhibin was focal to patchy in 16% of cases. We conclude that ovarian Sertoli cell tumor should be added to the growing list of WT1-positive tumors. This marker is useful for the distinction of Sertoli cell tumor from endometrioid tumors and carcinoid. The diagnostic utility of WT1 in Sertoli cell tumor is similar to inhibin but better than that of calretinin.

Sertoliform Endometrioid Carcinoma of the Endometrium With Dual Immunophenotypes for Epithelial Membrane Antigen and Inhibin ??

We report a rare case of sertoliform endometrioid carcinoma of the endometrium in a 71-year-old African American woman who presented with postmenopausal bleeding. Her medical condition was remarkable for hypertension, diabetes, and obesity. She underwent total hysterectomy, right salpingo-oophorectomy and lymph node sampling. The endometrium was occupied by a 4.5-cm solid polypoid tumor, which grossly invaded into the myometrium. Microscopically, the tumor consisted of small hollow tubules, anastomosing cords and trabeculae, and tightly packed nests. Microglandular areas mimicking adult granulosa cell tumors were also present. But true Call-Exner bodies were absent. Component of typical endometrioid carcinoma was noted only focally. The uninvolved endometrium demonstrated atypical complex hyperplasia. The tumor cells were diffusely immunoreactive for epithelial membrane antigen, estrogen receptor, and progesterone receptor (PR), and focally for vimentin. The tumor cells were also diffusely positive for inhibin alpha and CD99. Immunostains for other sex cord markers (calretinin, WT-1, and Melan-A) were also positive in approximately 30% to 40% of the tumor cells. Immunostains for CD10, smooth muscle actin, desmin, or HHF35 were negative. Two ovarian sertoliform endometrioid carcinomas from our archived tissue were, however, immunoreactive for epithelial membrane antigen but negative for inhibin alpha. Despite the prominent sertoliform features, both histologically and immunohistochemically, the tumor was of a high-grade endometrial carcinoma and will likely behave as such. As of today, dual differentiation of epithelium and sex cord by immunohistochemical staining has not been demonstrated in sertoliform endometrioid carcinomas of either endometrial or ovarian origin. Our case is the first documentation of such example and suggests that endometrial carcinoma can undergo true sex cord differentiation.

Immunhistochemische Keimstrangmarker

Sex cord markers comprise proteins and hormones that are produced in sex cord-derivatives in normal ovaries and testes as well as in gonadal sex cord-stromal tumors. Sex cord markers (e.g. inhibin-alpha) are used clinically as serum tumor markers. Immunohistochemical staining of sex cord markers may be helpful in the differential diagnosis of ovarian sex cord-stromal tumors versus surface epithelial-stromal tumors, germ cell tumors, other ovarian tumors, and ovarian metastases. Inhibin-alpha has been shown to be the most specific marker of sex cord differentiation. In comparison, calretinin is a somewhat more sensitive albeit less specific marker. Currently, an immunohistochemical panel including inhibin-alpha and calretinin is considered most helpful in the differential diagnosis of ovarian sex cord-stromal tumors. CD99, Müllerian inhibiting substance (MIS), melan A and CD10, being sex cord markers of limited sensitivity and specificity, should only be used as part of an antibody panel in specific diagnostic settings. EMA, CK7 and chromogranin are considered additional markers that may be useful in the differential diagnosis of ovarian sex cord-stromal tumors.

Comparative analysis of alternative and traditional immunohistochemical markers for the distinction of ovarian sertoli cell tumor from endometrioid tumors and carcinoid tumor: A study of 160 cases

The main neoplasms in the differential diagnosis for primary ovarian tumors with a tubule-rich pattern are pure Sertoli cell tumor, endometrioid tumors (including borderline tumor, well-differentiated carcinoma, and the sertoliform variant of endometrioid carcinoma), and carcinoid tumor. Because traditional immunohistochemical markers [pan-cytokeratin (pan-CK), low molecular weight cytokeratin (CK8/18), epithelial membrane antigen (EMA), inhibin, calretinin, CD99, chromogranin, and synaptophysin] can occasionally have diagnostic limitations, the goal of this study was to determine whether or not any alternative markers [cytokeratin 7 (CK7), estrogen receptor (ER), progesterone receptor (PR), CD10, and CD56] have better diagnostic utility when compared with traditional markers for this differential diagnosis. Immunohistochemical stains for alternative, as well as traditional, markers were performed on the following primary ovarian tumors: pure Sertoli cell tumor (n = 40), endometrioid borderline tumor (n = 38), sertoliform endometrioid carcinoma (n = 13), well-differentiated endometrioid carcinoma (n = 27), and carcinoid tumor (n = 42). Extent and intensity of immunostaining were semiquantitatively scored. In addition, immunohistochemical composite scores (ICSs) in positive cases were calculated on the basis of the combination of extent and intensity scores. Cytokeratin 7 (CK7) was positive in 97% of endometrioid tumors, 13% of Sertoli cell tumors, and 24% of carcinoid tumors. The differences in the mean ICSs for endometrioid tumors versus Sertoli cell tumor or carcinoid tumor were statistically significant (P values ranging from <0.001 to 0.018). ER and PR were positive in 87% and 86% of endometrioid tumors, 8% and 13% of Sertoli cell tumors, and 2% each of carcinoid tumors, respectively. The differences in the mean ICSs for endometrioid tumors versus Sertoli cell tumor were statistically significant (P values ranging from <0.001 to 0.012). Among the epithelial markers, EMA seemed to be the most discriminatory but only slightly better than CK7, ER, or PR. Pan-CK and CK8/18 were not helpful. CD10 showed overlapping patterns of expression in all categories of tumors. Among the sex cord markers, CD10 was markedly less useful than inhibin or calretinin; CD99 was not discriminatory. CD56 showed overlapping patterns of expression in all categories of tumors. Among the neuroendocrine markers, CD56 was less useful than chromogranin or synaptophysin. When traditional immunohistochemical markers are problematic for the differential diagnosis of ovarian Sertoli cell tumor versus endometrioid tumors versus carcinoid tumor, adding CK7, ER, and/or PR to a panel of markers can be helpful. Endometrioid tumors more frequently express CK7, ER, and PR and show a greater extent of immunostaining in contrast to Sertoli cell tumor and carcinoid tumor. Compared with traditional epithelial markers, CK7, ER, and PR are nearly as advantageous as EMA. Inhibin is the most discriminatory sex cord marker, and CD10 is not helpful in the differential diagnosis. Chromogranin and synaptophysin are excellent discriminatory markers for carcinoid tumor, and CD56 is neither sufficiently sensitive nor specific enough for this differential diagnosis to warrant its use in routine practice.

The Anti-Mullerian hormone and ovarian cancer

The Anti-Mullerian hormone (AMH), which is produced by fetal Sertoli cells, is responsible for regression of Mullerian ducts, the anlagen for uterus and Fallopian tubes, during male sex differentiation. Ovarian granulosa cells also secrete AMH from late in fetal life. The patterns of expression of AMH and its type II receptor in the post-natal ovary indicate that AMH may play an important role in ovarian folliculogenesis. Recent advances in the physiological role of AMH has stimulated interest in the significance of AMH as a diagnostic marker and therapeutic agent for ovarian cancer. Currently, AMH has been shown to be a circulating marker specifically for granulosa cell tumour (GCT). Its diagnostic performance seems to be very good, with a sensitivity ranging between 76 and 93%. In patients treated for GCT, AMH may be used post-operatively as marker for the efficacy of surgery and for disease recurrence. Based on the physiological inhibitory role of AMH in the Mullerian ducts, it has been proposed that AMH may inhibit epithelial ovarian cancer cell both in vitro and in vivo. These observations will be the basis for future research aiming to investigate the possible clinical role of AMH as neo-adjuvant, or most probably adjuvant, therapy for ovarian cancer.

Uterine tumour resembling ovarian sex cord tumour is an immunohistochemically polyphenotypic neoplasm which exhibits coexpression of epithelial, myoid and sex cord markers

AIMS

To describe the clinicopathological and immunohistochemical findings in four cases of uterine tumour resembling ovarian sex cord tumour (UTROSCT).

METHODS

Four UTROSCTs were stained with a wide range of antibodies, including epithelial (AE1/3, epithelial membrane antigen), myoid (desmin, alpha smooth muscle actin, h-caldesmon), sex cord (alpha inhibin, calretinin, melan A, CD99) and neuroendocrine (chromogranin, CD56) markers as well as hormone receptors (oestrogen receptor, progesterone receptor, androgen receptor), vimentin, CD10, WT1 and HMB45.

RESULTS

The tumours ranged from 0.8 to 19.5 cm. Three were relatively well circumscribed intramural myometrial lesions; the other was a pedunculated mass attached to the uterine serosa. The tumours were variably composed of solid, corded, trabecular, nested, glandular and retiform arrangements of tumour cells. In three cases, cells with eccentric nuclei and abundant eosinophilic cytoplasm, resulting in a rhabdoid appearance, were a prominent feature. Three cases were diffusely positive with AE1/3 and all with epithelial membrane antigen. Positivity with myoid markers was common with 3, 4 and 1 case respectively staining with desmin, alpha smooth muscle actin and h-caldesmon; 2, 4, 1 and 2 cases respectively were positive with alpha inhibin, calretinin, melan A and CD99. All were chromogranin negative and exhibited diffuse strong staining with CD56. All were diffusely positive with oestrogen receptor, progesterone receptor, vimentin and WT1. Three cases were androgen receptor positive and all were CD10 and HMB45 negative.

CONCLUSIONS

UTROSCT exhibits a polyphenotypic immunophenotype with coexpression of markers of epithelial, myoid and sex cord lineage as well as hormone receptors.

Immunohistochemical and functional biomarkers of value in female genital tract lesions

There has been a marked expansion in the literature pertaining to the use of immunohistochemical markers in female genital tract pathology, especially with regard to diagnosis. This review provides a survey of the antibodies commonly used in the diagnosis of gynecological lesions grouped as to function or type. Prognostic or predictive markers are also discussed where appropriate, although few of these are of value in everyday practice. It is stressed that when immunohistochemistry is used diagnostically, panels of markers provide better information than reliance on a single antibody.

Immunohistochemical study of the expression of adhesion molecules in ovarian serous neoplasms

To clarify possible roles of adhesion molecules including E-cadherin, beta- and gamma-catenin, CD44s, CD44v6, CD56, and CD99 in ovarian serous neoplasms, an immunohistochemical study was undertaken for 23 benign, 40 borderline, and 95 malignant ovarian serous neoplasms using tissue microarray (TMA). Significantly reduced expression of E-cadherin, and overexpression of CD44s, CD56, and CD99 were more frequently observed in adenocarcinomas than in benign and borderline tumors. Expression of CD44v6 and nuclear beta- and gamma-catenin were detected only in borderline tumors and adenocarcinomas. Reduced expression of E-cadherin was also correlated with high tumor grade (P=0.03), presence of peritoneal seeding (P=0.03), and low overall survival rate (P=0.02). Overexpression of CD44s was significantly associated with high tumor grade (P=0.04), advanced stage (P=0.03), and low overall survival rate (P=0.02). CD56 was increasingly expressed in the case of advanced stage (P=0.005) and peritoneal seeding (P=0.001). Nuclear staining for gamma-catenin was correlated with tumor progression (P=0.004) and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.02). Only CD44s expression and stage were correlated with overall survival in multivariate study. These results suggest that although E-cadherin, CD44s, CD56, and nuclear gamma-catenin immuno-expression seem to be useful prognostic markers for serous neoplasm of the ovary, CD44s expression and FIGO stage are independent prognostic factors.

Expression profiling of EWS/FLI identifies NKX2.2 as a critical target gene in Ewing's sarcoma

Our understanding of Ewing's sarcoma development mediated by the EWS/FLI fusion protein has been limited by a lack of knowledge regarding the tumor cell of origin. To circumvent this, we analyzed the function of EWS/FLI in Ewing's sarcoma itself. By combining retroviral-mediated RNA interference with reexpression studies, we show that ongoing EWS/FLI expression is required for the tumorigenic phenotype of Ewing's sarcoma. We used this system to define the full complement of EWS/FLI-regulated genes in Ewing's sarcoma. Functional analysis revealed that NKX2.2 is an EWS/FLI-regulated gene that is necessary for oncogenic transformation in this tumor. Thus, we developed a highly validated transcriptional profile for the EWS/FLI fusion protein and identified a critical target gene in Ewing's sarcoma development.

The use of immunohistochemistry in the differential diagnosis of tumors of the testis and paratestis

Although most testicular and paratesticular tumors can be recognized by their light microscopic features, some raise significant differential diagnostic questions. Immunohistochemical staining has proved of significant value in this situation. There is still a role for the traditional markers, including placental-like alkaline phosphatase and alpha-fetoprotein, but newer markers provide additional support and often have greater sensitivity and specificity for many diagnoses. OCT4 is virtually 100% sensitive and specific for seminoma, embryonal carcinoma, and intratubular germ cell neoplasia, unclassified type. Inhibin-alpha, among testicular tumors, is limited to those in the sex cord-stromal category or those having adrenocortical-type differentiation (testicular tumor of the adrenogenital syndrome) or of trophoblastic lineage. Calretinin is another positive marker for the sex cord-stromal tumors but has less specificity. Additional markers, including differential cytokeratins, c-kit, CD30, epithelial membrane antigen, S-100, melan-A, and others, are useful in specific situations. This article reviews the application of immunohistochemical markers for a number of differential diagnostic considerations in the testis and paratestis categorized according to their light microscopic patterns.

Immunohistochemistry as a diagnostic aid in the evaluation of ovarian tumors

Aspects of immunohistochemistry (IHC), which are useful in the diagnosis of ovarian tumors (mostly neoplasms but also a few tumor-like lesions), are discussed. The topic is first approached by considering the different growth patterns and cell types that may be encountered. Then a few other specific situations in which IHC may assist are reviewed. Selected findings largely, or only, of academic interest are also mentioned. One of the most common situations in which IHC may aid is in the evaluation of tumors with follicles or other patterns which bring a sex cord-stromal tumor into the differential. The distinction between a sex cord tumor and an endometrioid carcinoma with sex-cord-like patterns may be greatly aided by the triad of epithelial membrane antigen (EMA), inhibin, and calretinin, the latter two being typically positive and EMA negative in sex cord tumors, the converse being typical of endometrioid carcinoma. It should be emphasized that granulosa cell tumors may be inhibin negative and, albeit less specific, calretinin is more reliable in evaluating this particular issue. Lack of staining for inhibin and calretinin may also be supportive in leading to consideration of diverse other neoplasms that may form follicles, including metastatic tumors as varied as carcinoid and melanoma. The well-known staining of the latter neoplasm for S-100 protein and HMB-45 may be very helpful in evaluating melanomas with follicular or other unusual patterns, a challenging aspect of ovarian tumor interpretation. The most common monodermal teratoma, struma ovarii, usually has an overt follicular pattern and is easily recognized, but recognition of unusual appearances ranging from oxyphilic to clear cell to various patterns of malignant struma may be greatly aided by a thyroglobulin or TTF 1 stain. IHC for neuroendocrine markers may assist in the diagnosis of primary and metastatic carcinoid tumor. The broad differential diagnosis of glandular neoplasms with an endometrioid-pseudoendometrioid morphology, or mucinous cell type, has been the subject of much exploration in recent years, particularly the distinction between primary and metastatic neoplasms. The well-known CK7 positive, CK20 negative phenotype of primary endometrioid carcinoma, and the converse profile in most metastatic large intestinal adenocarcinomas with a pseudoendometrioid morphology, has been much publicized but albeit an appropriate supportive adjunct in many cases, exceptions from the typical staining pattern may be encountered. It is even less helpful in the case of primary versus metastatic mucinous neoplasia. Evaluation of the expression of mucin gene products has shown mixed, essentially unreliable, results. Experience with other new markers, such as CDX-2, villin, beta catenin, and P504S (racemase), is limited but is in aggregate promising with regard to providing some aid in this area. The rare differential of metastatic cervical adenocarcinoma versus primary ovarian mucinous or endometrioid carcinoma may be aided by strong p16 staining of the former. Staining for alpha-fetoprotein may aid in confirming the diagnosis of endometrioid-like (and hepatoid) variants of yolk sac tumor. Ependymoma of the ovary may also have an endometrioid-like glandular pattern, but positive stains for glial fibrillary acidic protein contrast with the negative results in others neoplasms with a similar pattern. Immunostains may be very helpful in the evaluation of oxyphilic tumors and tumor-like lesions and in some unusual forms of clear cell neoplasia, such as clear cell struma, both subjects being reviewed herein. Immunostains may highlight both the presence and extent of epithelial cells in a variety of circumstances, including microinvasive foci in cases of serous borderline tumors and mucinous carcinomas, and in determining the extent of carcinoma cells and reactive cells within mural nodules of mucinous neoplasms. As in tumor pathology in general, various markers may be crucial in the diagnosis of small round cell tumors of the ovary, and familiar markers of epithelial, lymphoid, leukemic, and melanocytic neoplasms may assist in the analysis of high grade tumors with a poorly differentiated carcinoma, lymphoma-granulocytic sarcoma, malignant melanoma differential. The evaluation of ovarian cystic lesions may be aided by thyroglobulin or TTF 1 (cystic struma), glial fibrillary acid protein (ependymal cysts), and inhibin-calretinin (follicle cysts and unilocular granulosa cell tumors). Stains for trophoblast markers may occasionally aid in the evaluation of germ cell tumors, although routine stains should usually suffice; they may be of academic interest in confirming trophoblastic differentiation in some high grade surface epithelial carcinomas.

New evidence for the origin of intracranial germ cell tumours from primordial germ cells: expression of pluripotency and cell differentiation markers

Primary intracranial germ cell tumours are rare neoplasms that occur in children and adolescents. This study examined both the biology and the origin of these tumours, as it has been hypothesized that they originate from a totipotent primordial germ cell. We applied recent knowledge from gonadal germ cell tumours and analysed expression of a wide panel of stem cell-related proteins (C-KIT, OCT-3/4 (POU5F1), AP-2gamma (TFAP2C), and NANOG) and developmentally regulated germ cell-specific proteins (including MAGE-A4, NY-ESO-1, and TSPY). Expression at the protein level was analysed in 21 children and young adults with intracranial germinomas and non-germinomas, contributing to a careful description of these unusual tumours and adding to the understanding of pathogenesis. Stem cell related proteins were highly expressed in intracranial germ cell tumours, and many similarities were detected with their gonadal equivalents, including a close similarity with primordial germ cells. A notable difference was the sex-specific expression of TSPY, a gene previously implicated in the origin of gonadoblastoma. TSPY was only detected in germ cell tumours in the central nervous system (CNS) from males, suggesting that it is not required for the initiation of malignant germ cell transformation. The expression of genes associated with embryonic stem cell pluripotency in CNS germ cell tumours strongly suggests that these tumours are derived from cells that retain, at least partially, an embryonic stem cell-like phenotype, which is a hallmark of primordial germ cells.

Granulosa Cell Tumor–like Variant of Endometrioid Carcinoma of the Ovary Exhibiting Nuclear Clearing With Biotin Activity: A Subtype Showing Close Macroscopic, Cytologic, and Histologic Similarity to Adult Granulosa Cell Tumor

Context.—The sex cord–like variant of endometrioid carcinoma of the ovary shows many similarities to Sertoli-Leydig cell tumor and granulosa cell tumor. However, few cases of the granulosa cell tumor–like variant have been reported, suggesting this tumor might often be hidden under the diagnosis of granulosa cell tumor.

Objective.—To investigate the similarities and differences between the granulosa cell tumor–like variant of endometrioid carcinoma and granulosa cell tumor of the ovary and to evaluate a newly observed feature, namely, nuclear clearing (or optically clear nuclei), in this variant tumor.

Design.—A comparative macroscopic, cytologic, histopathologic, and immunohistochemical study in specimens obtained from the following patients: 1 patient with granulosa cell tumor–like variant of endometrioid carcinoma diagnosed by frozen section examination, 3 patients with granulosa cell tumor, and 6 patients with classic endometrioid carcinoma.

Results.—The granulosa cell tumor–like variant showed close macroscopic, cytologic, and microscopic similarities to granulosa cell tumor. However, the 2 tumors could be differentiated immunohistochemically. The former also showed intense staining for progesterone receptors and contained nonmorular nests that exhibited the so-called nuclear clearing with biotin activity.

Conclusion.—Because the granulosa cell tumor–like variant is pathologically similar to granulosa cell tumor, showing only some dissimilarities to the latter, it can easily be misdiagnosed if the possibility of this variant is not kept in mind. Identification of the typical endometrioid histologic features or related lesions or immunohistochemistry may lead to a proper diagnosis. The observation of nuclear clearing with biotin activity in nonmorular nests suggests that this tumor has endometrioid epithelial characteristics.

Ovarian carcinomas, including secondary tumors: diagnostically challenging areas

The differential diagnosis of ovarian carcinomas, including secondary tumors, remains a challenging task. Mucinous carcinomas of the ovary are rare and can be easily confused with metastatic mucinous carcinomas that may present clinically as a primary ovarian tumor. Most of these originate in the gastrointestinal tract and pancreas. International Federation of Gynecology and Obstetrics (FIGO) stage is the single most important prognostic factor, and stage I carcinomas have an excellent prognosis; FIGO stage is largely related to the histologic features of the ovarian tumors. Infiltrative stromal invasion proved to be biologically more aggressive than expansile invasion. Metastatic colon cancer is frequent and often simulates ovarian endometrioid adenocarcinoma. Although immunostains for cytokeratins 7 and 20 can be helpful in the differential diagnosis, they should always be interpreted in the light of all clinical information. Occasionally, endometrioid carcinomas may exhibit a microglandular pattern simulating sex cord-stromal tumors. However, typical endometrioid glands, squamous differentiation, or an adenofibroma component are each present in 75% of these tumors whereas immunostains for calretinin and alpha-inhibin are negative. Endometrioid carcinoma of the ovary is associated in 15-20% of the cases with carcinoma of the endometrium. Most of these tumors have a favorable outcome and they most likely represent independent primary carcinomas arising as a result of a Mullerian field effect. Although the criteria for distinguishing metastatic from independent primary carcinomas rely mainly upon conventional clinicopathologic findings, loss of heterozygosity and gene mutation analyses can be helpful. Transitional cell carcinomas are distinguished from undifferentiated carcinomas by the presence of thick, undulating papillae with smooth luminal borders, microspaces, and tumor cells with distinctive 'urothelial' appearance. Krukenberg tumors are metastatic adenocarcinomas traditionally perceived as composed of mucin-filled signet-ring cells associated with a striking proliferation of the ovarian stroma but many variations on this pattern occur.

Sertoli Cell Tumors of the Ovary

Ovarian Sertoli cell tumors are rare, and their morphologic spectrum, behavior, and factors influencing the latter are not clearly established. They may be mimicked by many different tumors, some of them more frequent than Sertoli cell tumors; immunohistochemistry may aid in this differential, but its role has not been analyzed in a large series. We studied the clinicopathologic features of 54 Sertoli cell tumors, including the immunohistochemical profile of 23 of them. The patients, 6 of whom had Peutz-Jeghers syndrome, ranged from 2 to 76 years of age (mean, 30 years). Eleven patients had estrogenic and 4 had androgenic manifestations. The tumors ranged from 0.8 to 30 cm, with the majority being in the range of 4 to 12 cm. They were all unilateral, usually solid, and often yellow. The predominant microscopic pattern was tubular, seen, albeit often only focally, in all tumors; other patterns were cords or trabeculae (28), diffuse (21), pseudopapillary (4), retiform (3), islands or alveolar arrangements (3), and spindled (3). The tubules were solid or hollow with the former being somewhat more common. Delicate septa were occasionally seen and were conspicuous in areas of one tumor. The stroma was abundant in 15 tumors with marked sclerosis in 4. The cells usually had pale to occasionally densely eosinophilic cytoplasm, but 6 tumors were composed of cells with prominent foamy cytoplasm, falling in the category of "lipid-rich" Sertoli cell tumor, and one had cells with clear non-foamy cytoplasm. Forty-four tumors were stage I (42 of them were stage Ia and 2 were stage Ic), 1 was stage II, 3 were stage III, and 6 were not adequately staged. Follow-up was available for 27 patients with stage I tumors, and all were alive and well at last follow-up except for 2 patients with stage Ia and 1 with stage Ic disease. Those 3 patients had pelvic-abdominal recurrences 18, 36, and 9 months, respectively, after the initial diagnosis. Two of the three clinically malignant stage I tumors had moderate to severe cytologic atypia and brisk mitotic activity (>5 or more mitoses/10 high power fields [HPFs]), and one of these had tumor cell necrosis. Among the 10 clinically benign stage I tumors with more than 5 years of follow-up, only 3 had >5 mitoses/10 HPFs, but none had more than mild cytologic atypia and none had tumor cell necrosis. Two of the three patients with stage III disease had follow-up information and one was alive at 16 months and the second developed splenic metastases 2 years after the initial diagnosis. Two of the three stage III tumors had at least moderate cytologic atypia and brisk mitotic activity. Immunohistochemical stains showed positivity for AE1/3-Cam5.2 in 15 of 23 tumors; Epithelial membrane antigen (EMA) was negative in all the tumors. Inhibin was positive in 18 of 22 tumors, calretinin in 10 of 20, CD99 in 19 of 22, vimentin in 17 of 18, smooth muscle actin in 4 of 18, neuron specific enolase in 8 of 16, S-100 in 2 of 20, and chromogranin was negative in all 21 cases studied. Although Sertoli cell tumors usually have a distinctive tubular pattern that facilitates the diagnosis, other patterns may occasionally predominate, causing confusion with various other primary and metastatic ovarian tumors. EMA, inhibin, and chromogranin represent the most helpful triad of immunomarkers serving to exclude two common mimics of Sertoli cell tumors (endometrioid carcinoma [inhibin-; EMA+; chromogranin-] and carcinoid tumor [inhibin-; EMA+; chromogranin+]). Although CD99 and calretinin are often expressed in these tumors, they are much less specific and not as helpful in the differential diagnosis. Most Sertoli cell tumors are stage I, unilateral, cytologically bland, and clinically benign, but occasional examples are high stage, and about 11% of stage I tumors have worrisome histologic features that may portend an adverse outcome. The tumors typically occur in young females, sometimes children who typically present with sexual precocity, and occasional patients have Peutz-Jeghers syndrome.

Expression of CD99 in pleomorphic carcinomas of the lung

Pleomorphic carcinoma of the lung (PCL) is characterized by a mixture of sarcomatoid and carcinoma components, and a poor prognosis. However, no immunophenotype of tumor markers has been characterized in PCL. To characterize the immunophenotype for CD99 in PCL, we performed an immunohistochemical evaluation of PCLs for thyroid transcription factor-1 (TTF-1), cytokeratin (CK) 7 and 20, and for CD99. CD99 was found to be expressed in both carcinomatous (47%) and sarcomatous components such as spindle cells (92%) and giant cells (57%). In the case of spindle cells, CK7 was expressed in 6 cases (46%) and TTF-1 in 2 cases (15%), whereas for giant cells CK7 was expressed in 8 cases (57%) and TTF-1 in one case (7%). However, CK20 was not expressed in either the carcinomatous or sarcomatous components in any case. Thus, CD99 was found to be widely expressed in both sarcomatous and carcinoma component in PCL. A clinicopathological analysis showed no direct correlation between the expression of CD99 and the clinical indices (stage, survival rate, invasion) of PCL.

Inhibin alpha and beta expression in ovarian stromal tumors and their histological equivalences

Inhibin is a heterodimeric protein hormone that appears to be a sensitive immunohistochemical marker of sex cord-stromal tumors. Although sex cord-stromal tumors can usually be distinguished from ovarian epithelial tumors or their metastases by morphology or by using antibodies against intermediate filaments, the diagnosis remains difficult in rare situations in such cases as sarcomatoid granulosa-theca cell tumors, ovarian small cell carcinomas, or soft-tissue sarcomas. The purposes of this study were to examine inhibin alpha and beta immunoreactivity in a wide range of gonadal stromal neoplasms and to assess its value in the differential diagnosis of problematic tumors. A total of 108 paraffin-embedded ovarian and extraovarian tumors were examined immunohistochemically by using anti-alpha inhibin and anti-beta inhibin. Inhibin alpha immunostaining was identified in 46 (81%) of 57 gonadal stromal tumors, one (14%) of seven endometrial stromal tumors, and one (50%) of two primary ovarian carcinoid tumors. Inhibin beta immunostaining was detected in 55 (96%) of 57 gonadal stromal tumors, two (29%) of seven endometrial stromal tumors, one (50%) of two dysgerminomas, and in all of two (100%) primary ovarian carcinoid tumors. Inhibin alpha expression was not detected in any ovarian surface epithelial tumor cells. Some surface epithelial tumors showed stromal inhibin alpha (15% of cases) and inhibin beta (48% of cases) positivity. Weak immunoreactivity for inhibin beta was found in most (83% of cases) ovarian surface epithelial tumors. Two ovarian Burkitt lymphomas were negative for inhibin alpha and beta. Inhibin alpha is a sensitive immunohistochemical marker of gonadal stromal tumors and is of value in the differential diagnosis of ovarian neoplasia. Inhibin beta is a nonspecific marker for ovarian neoplasms, showing expression on tumor and stromal cells of different epithelial or stromal tumors.

Comparative Immunohistochemical Analysis of Granulosa and Sertoli Components in Ovarian Sex Cord-Stromal Tumors with Mixed Differentiation: Potential Implications for Derivation of Sertoli Differentiation in Ovarian Tumors

Granulosa cell tumors of the ovary occasionally show admixed Sertoli components, just as tumors that are predominantly Sertoli or Sertoli-Leydig cell tumors can contain minor granulosa elements. Although the immunoprofiles of pure granulosa cell tumors and pure Sertoli cell tumors have been characterized, little is known regarding what immunophenotypic relationships exist between the granulosa and Sertoli components in ovarian sex cord-stromal tumors that contain both elements. Furthermore, it is not completely understood why sex cord-stromal tumors of the ovary with female-type (granulosa) differentiation can produce male-type (Sertoli) differentiation. To better understand why simultaneous differentiation into female-type and male-type components occurs, eight tumors with mixed differentiation were stained with a panel of antibodies to androgen receptor (AR), calretinin, CD10, CD99, estrogen receptor, inhibin, Ki-67, low molecular weight cytokeratin, pancytokeratin, progesterone receptor, p53, and vimentin. Immunohistochemical composite scores were determined separately for the matched pairs of granulosa and Sertoli components in each case. Differences between both components were statistically analyzed using the Wilcoxon signed rank test. AR and vimentin expression showed a difference at the 10% statistical significance level (p < 0.1), demonstrating higher levels of expression in the granulosa components. The differences between the granulosa and Sertoli components in expression of CD99, inhibin, or pancytokeratin were not statistically significant (p > 0.1, each). Statistical calculations could not be made for calretinin, CD10, estrogen receptor, Ki-67, low molecular weight cytokeratin, progesterone receptor, or p53, although the overall mean levels of expression of CD10 and low molecular weight cytokeratin were substantially higher in the Sertoli components. Not surprisingly, the granulosa and Sertoli components of ovarian sex cord-stromal tumors with mixed differentiation show overlapping immunophenotypic profiles consistent with derivation from a common lineage rather than reflecting a composite tumor. However, because components of a sex cord-stromal tumor simultaneously differentiate along granulosa or Sertoli lines, they seem to show preferential expression of certain antigens. CD10 and low molecular weight cytokeratin are more often associated with Sertoli cell differentiation, whereas AR and vimentin expression seem to reflect granulosa differentiation.

The role of calretinin, inhibin, melan-A, BCL-2, and C-kit in differentiating adrenal cortical and medullary tumors: an immunohistochemical study

Morphologic distinction between adrenal cortical and medullary tumors can be difficult. Previous studies have shown inhibin, melan-A, and BCL-2 to be useful markers for adrenal cortical tumors. We have recently observed a high level of calretinin expression in normal adrenal cortex but not the medulla and therefore evaluated its diagnostic application for adrenal tumors in comparison with inhibin, melan-A, and BCL-2. C-kit is a transmembrane tyrosine kinase receptor. Immunodetection of c-kit expression has been recently used for tumor diagnosis, and c-kit-positive tumors can potentially benefit from kit kinase inhibitor treatment. Although c-kit expression was reported in adrenal medulla and pheochromocytoma, it has not been evaluated in adrenal cortical tumors. In this study, 28 adrenal cortical tumors (12 carcinomas, 16 adenomas), 20 pheochromocytomas, and 20 extraadrenal paragangliomas were evaluated for calretinin, inhibin, melan-A, BCL-2, and c-kit expression by standard immunohistochemical assays on paraffin sections. The percentage of immunoreactivity in adrenal cortical tumors was as follows: calretinin, 96%; melan-A, 89%; inhibin, 92%; BCL-2, 20%; and c-kit, 5%. Normal adrenal medulla did not stain for c-kit but was positive for BCL-2. Eighty-six percent of pheochromocytomas stained for BCL-2 and none for calretinin, with the exception of the ganglioneuromatous areas in composite pheochromocytomas (n = 5). Extraadrenal paragangliomas showed reactivity with calretinin in 25%, melan-A in 5%, inhibin in 16%, BCL-2 in 38%, and c-kit in 8% of the cases. Our results indicate that calretinin is the most sensitive among all the adrenal markers tested. Like melan-A and inhibin, calretinin is also a very specific marker in differentiating cortical from medullary adrenal tumors. In addition, calretinin can be used to confirm a composite pheochromocytoma. BCL-2 does not appear to be useful in differentiating adrenal cortical from medullary tumors. C-kit is not useful in the diagnosis of adrenal tumors, and kit kinase inhibitor might have a limited role in the treatment of adrenal tumors and paraganglioma because of the low frequency of c-kit expression in these tumors.

Inhibin immunohistochemical staining: a practical approach for the surgical pathologist in the diagnoses of ovarian sex cord-stromal tumors

Through a brief introduction of inhibin history, characteristics of the antibody against inhibin, and normal tissue distribution of alpha-inhibin expression, this comprehensive review focuses on a practical approach to using alpha-inhibin in the differential diagnosis of ovarian sex cord-stromal tumors (SCSTs). Alpha-inhibin has become a most useful immunohistochemical marker of gonadal SCST, regardless if the tumors are primary, recurrent, or metastatic. However, pathologic diagnosis of individual SCST is still based largely on morphologic criteria. Alpha-inhibin immunohistochemical (IHC) staining should be used only when a difficult morphologic diagnosis is encountered. In this perspective, alpha-inhibin and other properly selected markers should be ordered at the same time. This is simply because alpha-inhibin is not specific for SCSTs. Caution should be exercised in the interpretation of alpha-inhibin-positive cells, because a wide variety of primary and metastatic ovarian tumors may contain significant numbers of alpha-inhibin-positive stromal cells. As with other immunohistochemical stains, a panel of stains and comparison with the corresponding hematoxylin and eosin (H&E) slides is necessary, especially when staining patterns and cellular localization are in question. The antibody will not help to differentiate tumors within the category of SCST. The pattern or the intensity of staining in SCSTs does not predict tumor behavior, although there is a tendency of loss of alpha-inhibin expression in poorly differentiated Sertoli or Sertoli-Leydig cell tumors. In cases where metastatic granulosa or Sertoli-Leydig cell tumors are a concern, positive alpha-inhibin staining is diagnostic, but a negative result does not rule out metastatic disease. Calretinin has been recently recognized as a more sensitive, but less specific marker for SCSTs and it may be used to recognize an inhibin-negative SCST. In this review, we have listed nine of the most commonly encountered clinical scenarios where alpha-inhibin and other markers could be used in diagnostic surgical pathology of ovarian tumors.