Value of inhibin staining in gynecological pathology

Cytologic features of sex cord-stromal tumors in women

BACKGROUND

Gynecologic sex cord-stromal tumors (SCSTs) arise from sex cords of the embryonic gonad and may display malignant behavior. We describe the cytomorphologic features of SCSTs in females, including adult and juvenile granulosa cell tumors (AGCTs and JGCTs), Sertoli-Leydig cell tumors (SLCTs), and steroid cell tumors (SCTs).

METHODS

We retrieved available cytology slides from females with a histologic diagnosis of sex cord-stromal tumor between 2009 and 2020 from institutional archives and reviewed their cytoarchitectural features.

RESULTS

There were 25, 2, 2, and 1 cytology specimens from 19, 2, 2, and 1 patients (aged 7-90 years, median 57 years) with AGCT, JGCT, SLCT, and SCT, respectively. Features common to all SCSTs included 3-dimensional groups, rosettes, rare papillary fragments, abundant single cells and naked nuclei. Rosettes and a streaming appearance of cell groups were only seen in AGCTs, which also rarely featured eosinophilic hyaline globules and metachromatic stroma. AGCTs exhibited high nuclear:cytoplasmic (N:C) ratios, with mild nuclear pleomorphism, uniform nuclei with finely granular chromatin, nuclear grooves and small nucleoli; in contrast, other SCSTs lacked rosettes and nuclear grooves and had generally lower N:C ratios, greater nuclear pleomorphism, coarse chromatin and more abundant cytoplasm. Mitotic figures, necrosis, and inflammation were rarely identified.

CONCLUSIONS

AGCTs show cytomorphologic features that are distinct from those of other SCSTs. Careful evaluation of the cytological features and ancillary studies (eg, immunochemistry for FOXL2, inhibin and calretinin, or sequencing for FOXL2 mutations) can aid in the accurate diagnosis of these tumors.

Uterine tumor resembling ovarian sex cord tumor: a clinicopathological and immunohistochemical analysis of two cases and a literature review

A uterine tumor resembling an ovarian sex cord tumor (UTROSCT) is a rare type of neoplasm that is almost thoroughly differentiated towards ovarian sex cord elements. Because of abnormal uterine bleeding, a 64-year-old postmenopausal woman received total abdominal hysterectomy with bilateral salpingo-oophorectomy. Under a microscope, the tumor cells showed an anastomosing fascicular and trabecular pattern with a reticular architecture. Immunohistochemistry showed that the tumor cells were positive for calretinin, Wilm’s tumor-1, and vimentin. A 33-year-old woman who suffered from menorrhagia, and was treated for bilateral salpingectomy, total abdominal hysterectomy, and bilateral ovarian biopsy, was also studied. Using histology, the patient was diagnosed with UTROSCT as shown by CD99, smooth muscle actin, calretinin, vimentin, and desmin expression. As a type of rare uterine tumor, UTROSCT can be diagnosed based on morphological and immunohistochemical conditions. Generally, these tumors are benign, but can easily relapse through incomplete resection. Hysterectomy should be performed after completion of family planning.

Steroidogenesis in ovarian-like mesenchymal stroma of hepatic and pancreatic mucinous cystic neoplasms

Aim Mucinous cystic neoplasms (MCNs) occur in the ovary, pancreas, and retroperitoneum but very rarely in the liver. Mucinous cystic neoplasms are known to harbor ovarian-like mesenchymal stroma (OLS) expressing progesterone and estrogen receptors. In this study we evaluated steroidogenesis in OLS of 25 hepatic MCNs and 24 pancreatic MCNs. Methods Both steroid receptors and steroidogenic factors were immunohistochemically evaluated using H-scores and results were compared with those in 15 ovarian MCNs and 10 normal ovaries. Results Androgen receptor (AR) H-scores in OLS were significantly higher in hepatic, pancreatic, and ovarian MCN than those in normal ovaries. H-scores of cytochrome P450 17α-hydroxylase/c17-20 lyase (P450c17) and 5α-reductase-1 (5αRED-1) in the stroma were significantly higher in OLS of hepatic and pancreatic MCN than in the stroma of ovarian MCN and normal ovary. In tumor epithelium, AR H-scores were significantly higher in hepatic and pancreatic MCN than in ovarian MCN. In both hepatic and pancreatic MCN, a significant positive correlation was detected between AR H-score in the epithelium and P450c17 H-score in OLS (hepatic MCN: Pearson's r = 0.446, P = 0.025; pancreatic MCN: r = 0.432, P = 0.035). In pancreatic MCN, a significantly positive correlation was detected between AR H-score in the tumor epithelium and 5αRED-1 H-score in OLS (Pearson's r = 0.458, P = 0.024). Conclusions These results indicated that locally produced androgens in OLS could be pivotal for tumorigenesis of both hepatic and pancreatic MCN and influence epithelial cells, possibly in a paracrine fashion, which could represent biological significance of OLS in these neoplasms.

Microscopic Heterotopic Extraovarian Sex Cord-Stromal Proliferations: Expanding the Histologic Spectrum

Microscopic, heterotopic extraovarian sex cord-stromal proliferations have only recently been reported in the literature. We describe the largest series to date, of 30 cases of microscopic, incidentally detected, heterotopic extraovarian sex cord-stromal proliferation, in women aged 25-79 yr who had undergone surgery for a range of benign and malignant gynecologic conditions. In 14 patients the foci of proliferation comprised ovarian cortical stroma, in some cases with an ovarian fibroma-like appearance. Ten cases of adenofibroma and cystadenofibroma were also identified, including 1 Brenner adenofibroma; 2 cases comprised both ovarian cortical stroma and serous cystadenofibroma; 4 cases showed sex cord proliferation resembling microscopic adult granulosa cell tumors. Immunohistochemistry, where possible, confirmed the sex cord nature of the heterotopic proliferations. The foci of proliferation were <1-7 mm, and most were at the fimbrial end of the fallopian tube. These proliferations are likely to be encountered with increasing frequency as we sample the adnexa more extensively. Previous reports postulated that the proliferations probably represent embryonic rests caused by anomalous migration but we suggest that incorporation of exposed ovarian parenchymal tissue into the fimbrial stroma at the time of ovulation may be another possible cause.

Rare non-epithelial ovarian neoplasms: Pathology, genetics and treatment

Rare non-epithelial ovarian neoplasms have posed management challenges for many years. Their rarity means that most specialist practitioners will see one such case every several years, and most generalists may never see a case. The first step in management is to establish the correct diagnosis and this may necessitate specialist pathology review. Here, we review recent developments in the pathology, genetics and treatment of small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) and sex cord-stromal tumours. Pathologically, these tumours often display morphological overlap with other neoplasms; for example, SCCOHT overlaps with many other "small round blue cell" tumours. Specific immunohistochemical stains, while useful, may not always be definitive. The discovery of somatic mutations in FOXL2 (adult granulosa cell tumours) and germline and somatic mutations in DICER1 (Sertoli-Leydig cell tumours) and SMARCA4 (SCCOHT) has demonstrated the value of molecular investigation as an adjunct to traditional histopathological approaches. In addition, the presence of germline mutations in a significant proportion of some of these neoplasms points to the need for genetic counselling and testing, offering the prospect of prevention and early diagnosis. Treatment of these rare tumours, as a group, should be on the basis of sound oncological principles, given that level 1 evidence will almost always be lacking. The rationale for experimental therapies must be clearly established. In view of the complex issues involved in the management of these conditions, expert opinion in pathology, genetics and treatment may be essential to offer the patient and her family the best chance of a good outcome.

Fine needle aspiration cytology of cystic primary adult granulosa cell tumor of the ovary: Potential diagnostic pitfalls with other cystic ovarian lesions

INTRODUCTION

Fine needle aspiration(FNA) of cystic adult granulosa cell tumors(CAGCT) has been sporadically reported in the literature. We undertook a retrospective study to further elucidate the cytologic features on FNA material in order to avoid possible misinterpretation with other primary tumors of ovary.

MATERIALS AND METHODS

During 1992 and 2014, FNA of five cases of CAGCT were recorded.

RESULTS

The patient's age ranged from 28 to 62 years. One was bilateral and all cases involved right side of ovary. The size of tumor was 5.5 to 10 cm. FNA of the five CAGCT show similar cytologic features except one case. Four cases contained a background composed of histiocytic cells and debris material. The tumor cells were small with round to oval nuclei and fine chromatin pattern, inconspicuous nucleoli, scanty cytoplasm with rare intranuclear longitudinal grooves. Tumor cells were arranged in small groups as well as single cells were appreciated some of which were deprived of cytoplasm. Microfollicular or rosette pattern were vague, some of which contain amorphous material resembling Call-Exner bodies. In addition, two cases also showed prominent papillary component and one of which was misdiagnosed for serous papillary carcinoma. All five cases were surgically resected and CAGCT was confirmed.

CONCLUSIONS

FNA of CAGCT of ovary can be a challenging diagnosis as classic cytologic features may not be present and can be confused with benign follicular cyst especially when the ultrasound study favor benign cystic lesion. Rarely this tumor may show prominent papillary component and can be confused for a more clinically aggressive tumor such as papillary serous carcinoma. Diagn. Cytopathol. 2016;44:461-465. © 2016 Wiley Periodicals, Inc.

Ovarian mucinous epithelial neoplasm showing immunohistochemical pattern of lower gastrointestinal origin with stromal minor sex-cord elements: A case report

•We report a case of an ovarian mucinous cystadenoma that exhibited extensive sex-cord differentiation.•The ovarian tumor coincided with a uterine endometrial carcinoma.•The immunohistochemical pattern of mucinous epithelium of the ovarian tumor was suggestive of lower gastrointestinal origin.

Germ cell tumors of the ovary: an update

CONTEXT

The field of ovarian germ cell tumors (OGCTs) has remained relatively unchanged in the last 2 decades. However, the introduction of new stem cell pluripotency markers has provided a new understanding into the identification and taxonomy of OGCT types. New data have provided new insights into unusual teratoma-associated autoimmune disorders and the origin of gliomatosis peritonei.

OBJECTIVE

To review the impact of new pluripotency markers in the diagnosis of malignant OGCT (MOGCT) and analyze new nomenclature proposals and clinicopathologic entities.

DATA SOURCES

Ovarian germ cell tumors from routine material and expert consultation files at San Cecilio University Hospital, Granada, Spain, and the relevant literature were reviewed.

CONCLUSIONS

Although a correct diagnosis of MOGCT can often be made with histologic and classic immunohistochemical studies, the new immunohistochemical pluripotency markers give higher diagnostic accuracy. Germ cell tumors represent a caricature of the phases of normal embryonic differentiation from primordial germ and stem cells to extraembryonal and somatic tissue differentiation. Since every stage of differentiation and its related tumor type exhibit characteristic markers, the analysis of their expression facilitates tumor typing, thus complementing the use of classic antibodies. They also allow a more precise evaluation of the degree of immaturity in teratoma. The new term, primitive endodermal tumors, simplifies the understanding of the complex histology of the yolk sac tumor group, as this terminology encompasses its multiple endodermal differentiations. Recently described autoimmune encephalitis due to antibodies against the N-methyl-d-aspartate receptor has become the most frequent autoimmune disorder associated with ovarian teratoma.

WT1 expression in the female genital tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Application of immunohistochemistry to gynecologic pathology

CONTEXT

A large variety of tumors and lesions arise in the female genital tract. Although the majority of these can be correctly recognized on routine hematoxylin-eosin-stained slides, occasional cases present a diagnostic challenge. Immunohistochemical stains are extremely useful in resolving many of these problematic cases. As the knowledge in this area is constantly expanding, it is useful to have this updated information in a review form for easy access.

OBJECTIVE

To present our current knowledge of immunohistochemistry of the lesions of the female genital tract in a readily accessible form.

DATA SOURCES

The review is based on previously published articles on this topic.

CONCLUSIONS

Immunohistochemical stains help in reaching a conclusive diagnosis in a variety of problematic lesions seen in gynecologic pathology. As in any other system, immunohistochemical findings need to be interpreted in light of the clinical history and morphologic findings.

Ovarian-type stroma in hepatobiliary cystadenomas and pancreatic mucinous cystic neoplasms: an immunohistochemical study

We compared immunohistochemical expression of hepatocyte growth factor (HGF), c-met, alpha-inhibin, estrogen receptor (ER), and progesterone receptor (PR) in 10 pancreatic mucinous cystic neoplasms (PMCNs), 8 hepatobiliary cystadenomas (HBCs), and 6 simple liver cysts (SLCs).All HBCs and PMCNs were in women (mean ages, 45.7 and 54.9 years, respectively; P > .05). All HBCs had abundant stroma; PMCN stromal density was more variable (score, 3.0 vs 1.8; P < .05). Stroma in HBCs had greater ER and PR staining (both P < .05) and more consistent, focal, strong reactivity for alpha-inhibin than PMCNs (P < .05). SLCs were found in men and women, lacked ovarian-type stroma, and were negative for ER, PR, and alpha-inhibin. HGF expression was not significantly different in the epithelium of HBCs, PMCNs, and SLCs; c-met expression in the epithelium of HBCs and PMCNs was significantly stronger than in SLCs (P < .05). Differences in stromal density and ER, PR, and alpha-inhibin immunoreactivity in HBCs and PMCNs suggest that different hormonal environments in the liver and pancreas contribute to stromal variation. Up-regulation of c-met in HBCs and PMCNs suggests c-met activation in the pathogenesis of pancreaticobiliary cystic neoplasms.

CD56 Is a Sensitive and Diagnostically Useful Immunohistochemical Marker of Ovarian Sex Cord-Stromal Tumors

Ovarian sex cord-stromal tumors comprise a heterogeneous group of neoplasms with wide morphological diversity, and they can be mistaken for a variety of other tumors. Some types, including granulosa and Sertoli cell tumor, may be confused with a neuroendocrine neoplasm. CD56 is a widely used neuroendocrine marker with a high sensitivity for neuroendocrine tumors and is commonly used as part of a panel to distinguish between a neuroendocrine neoplasm and other tumors in the differential diagnosis. In this study, we investigate CD56 staining in ovarian sex cord-stromal tumors. CD56 staining has not previously been studied in this group of neoplasms. We stained a large series of ovarian sex cord-stromal neoplasms (n = 85) with CD56. Neoplasms studied were adult granulosa cell tumor (n = 40), juvenile granulosa cell tumor (n = 8), Sertoli cell tumor (n = 1), Sertoli-Leydig cell tumor (n = 14), Leydig cell tumor (n = 2), steroid cell tumor, not otherwise specified (n = 2), sclerosing stromal tumor (n = 1), sex cord tumor with annular tubules (n = 2), and fibroma (n = 15). Three uterine tumors resembling ovarian sex cord tumor were also studied. Nonneoplastic ovaries, including 3 cases of pregnancy-related granulosa or Sertoli cell proliferation, were also included. In nontumorous ovaries, granulosa cells of follicular and corpus luteum cysts were consistently negative. The normal ovarian stroma was diffusely positive, as were the 3 pregnancy-related proliferations. All sex cord-stromal tumors except one were positive with CD56; staining ranged from focal to diffuse but was usually diffuse involving more than 50% of tumor cells. Staining was usually membranous with weaker cytoplasmic positivity. CD56 immunoreactivity is almost universal in ovarian sex cord-stromal tumors of all the major morphological types and is of no value in distinguishing a sex cord-stromal and a neuroendocrine neoplasm. Since CD56 is an extremely sensitive marker of ovarian sex cord-stromal tumors, it may be useful in the diagnosis of this group of neoplasms, especially in cases which are alpha inhibin or calretinin negative, and in distinguishing these from mimics which are CD56 negative.

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.

Expression of estrogen and progesterone receptors and inhibin-alpha in hepatobiliary cystadenoma: an immunohistochemical study

To further characterize the immunohistochemical features of hepatobiliary cystadenoma with mesenchymal stroma, a battery of stains was performed on nine typical cases. All nine tumors had been resected from female patients who ranged in age from 30 to 59 years. Freshly cut sections were stained with antibodies to estrogen receptor (ER), progesterone receptor (PR), alpha-smooth muscle actin (SMA), inhibin-alpha, and cytokeratins (CK) 7, 8, 18, and 19. Nuclear staining of the mesenchymal stromal cells for ER and PR was present in all and seven out of nine cases, respectively. A strong cytoplasmic staining of the mesenchymal stromal cells for SMA was seen in all cases. A patchy pale cytoplasmic staining of the tumor epithelium for ER and PR was seen in five out of nine and four out of nine cases, respectively. Immunoreactivity of luteinized stromal cell for inhibin-alpha was documented in three out of nine cases. All tumors (nine out of nine) demonstrated strong cytoplasmic positivity of the epithelial lining of the cysts to CK7, CK8, CK18, and CK19, typical of biliary-type epithelium. The expression of ER, PR, and inhibin-alpha in the ovarian-like stroma supports the likely hormonal dependence of this tumor and probably explains its almost exclusive occurrence in women.

Primary Malignant Melanoma of the Ovary

Most malignant melanomas encountered in the ovary are metastatic, and the recent literature has focused on such neoplasms. Primary tumors are rare with most reports being only of single cases. When the tumor is associated with teratomatous elements from which it arises, not only is the diagnosis of melanoma much more likely to be made but also is a primary nature proven. However, although all the primary tumors likely are of teratomatous origin, evidence of such an origin may be effaced resulting in problems both in identifying the tumor as melanoma and in determining if it is primary or not. In this report, we describe 9 primary or probably primary ovarian melanomas and explore the varied problems the cases posed. The patients ranged from 18 to 72 years. The tumors, all of which were unilateral, ranged from 4 to 23 cm; only 2 were black. In 6 cases, there was an associated dermoid cyst or monodermal teratoma (struma ovarii), 5 in the ipsilateral and 1 in the contralateral ovary. The tumors were variously composed of large epithelioid cells with eosinophilic cytoplasm, small cells, spindle-shaped cells, or a combination, and in 5 cases, melanin pigment (Masson Fontana positive) was identified. In all cases, most of the tumor cells had prominent nucleoli. All neoplasms had a predominantly diffuse growth pattern with a focal nested architecture in 3 cases. Other noteworthy morphological features were tumor giant cells with wreath-like nuclei (4 cases), signet ring cells (1 case), clear cells (1 case), intranuclear pseudoinclusions (2 cases), a focally myxoid stroma (2 cases), a pseudopapillary appearance caused by degeneration (2 cases), and follicle-like structures (3 cases). In 1 case in a 21-year-old, there was associated hypercalcemia, and focally, the neoplasm, which contained follicle-like structures, resembled small cell carcinoma of the hypercalcemic type. All cases tested by immunohistochemistry were positive with 1 or more melanocytic markers, and electron microscopy performed in 3 cases revealed intracytoplasmic melanosomes or premelanosomes. The wide differential potentially includes neoplasms within most of the categories of primary ovarian neoplasia, as well as metastatic melanoma, and is facilitated by thorough sampling to identify teratomatous elements, by awareness of the spectrum of melanoma in the ovary, and by positivity with melanocytic markers. This is an area where electron microscopy can still also contribute useful information.

Ovarian Serous Cystadenofibroma With Stromal Sex Cord Elements

This report describes an ovarian serous cystadenofibroma, in a postmenopausal woman, which exhibited extensive sex cord differentiation, in the form of solid and hollow tubules resembling Sertoli cell elements, within the stroma. The sex cord elements, which were located just beneath the epithelium, were positive with both alpha inhibin and calretinin and negative with epithelial membrane antigen. They were also CD56 positive but negative with other neuroendocrine markers. True sex cord structures or sex cord-like elements have been described in ovarian adenosarcomas and pure stromal tumors, especially fibromas. However, as far as we are aware, these elements have not been reported in a serous cystadenofibroma. The endometrium exhibited simple hyperplasia, perhaps secondary to estrogenic activity of the sex cord elements. We discuss the significance of CD56 positivity of the sex cord elements.

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.

Endometrial polyp with sex cord-like pattern

We report on an unusual endometrial polyp in a postmenopausal woman taking tamoxifen for 7 years after surgical resection of a breast carcinoma. A 63-year-old woman with endometrial thickening was submitted to hysteroscopy with biopsy, which revealed a polyp with a sex cord-like pattern. The hysterectomy specimen showed florid adenomyosis, and in the background, there were rare sex cord-like foci. Immunohistochemistry can be useful in differentiating sex cord-like elements from metastatic breast cancer to endometrium. This is, to our knowledge, the first observation in literature correlated to tamoxifen intake.

Recent Advances in the Pathology and Classification of Ovarian Sex Cord-Stromal Tumors

In recent years, our knowledge of ovarian sex cord-stromal tumors has increased, and their classification has evolved. In this review, recent advances in the classification and pathology of ovarian sex cord-stromal tumors are discussed, and the controversy regarding the classification of sex cord tumor with annular tubules is addressed. The current classification is built on those of the past, and future classifications should improve on what is now in place incorporating new knowledge from more sophisticated clinicopathologic studies and advanced molecular techniques. This review emphasizes articles written in the 21st century as well as those that have significantly advanced our knowledge of sex cord-stromal tumors in past decades. The tumors in this group occur over a wide age range and are often unilateral. In difficult cases, immunocytochemistry provides improved diagnostic accuracy. The most useful immunohistochemical marker for their identification is alpha-inhibin, which is positive in most neoplasms in the sex cord-stromal group. The article concludes with a section discussing the pathogenesis of sex cord-stromal tumors.

Cancer progression: is inhibin alpha from Venus or Mars?

The inhibin field has been perplexed by the information that inhibin alpha is a tumour suppressor in mice yet is elevated in women with ovarian cancer. Furthermore, we have consistently observed a down-regulation or loss of inhibin alpha in prostate cancer patient samples and cell lines. However, our latest data have prompted us to re-evaluate the role of inhibin alpha in prostate and other cancers. Using the analogy of TGF-beta as a springboard for our hypothesis, we offer a unifying model whereby the previously conflicting observations in mice, men and women can be explained. We propose that initially inhibin alpha is tumour-suppressive and is expressed in benign and early-stage primary cancers. Tumour-suppressive inhibin alpha is then silenced as the tumour progresses but is reactivated as a pro-metastatic factor in advanced, aggressive cancers.

Inhibins in female and male reproductive physiology: role in gametogenesis, conception, implantation and early pregnancy

A great deal of new information has arisen in the recent years concerning inhibin physiology and clinical relevance in reproductive medicine. It is now recognized that the two inhibin isoforms, named inhibin A and inhibin B, are produced by the gonads in the course of gamete maturation and in women have a different pattern of secretion throughout the menstrual cycle. Since inhibins are also produced by placenta and fetal membranes, it has been suggested that there is an involvement in physiological adaptation of pregnancy. Evidence from several sources has underlined the clinical usefulness of the measurement of inhibin-related proteins in the diagnosis and follow-up of different fertility disturbances and early pregnancy viability. In the male, inhibin B is produced in the testis, principally by the Sertoli cells. Inhibin B expression and secretion are positively correlated with Sertoli cell function, sperm number, and spermatogenic status and are negatively correlated with FSH. This review covers the most recent advances on the role of inhibins in human reproductive function. Considerable progress in the understanding of inhibin physiology has resulted from selective measurement of the two inhibin molecular forms, named inhibin A and B. Newly recognized alterations of inhibin levels in gynaecological diseases as well as in normal and pathological pregnancy are discussed, with particular emphasis on the potential clinical usefulness of assessing inhibin levels in serum and other biological fluids.

The utility of calretinin, inhibin, and WT1 immunohistochemical staining in the differential diagnosis of ovarian tumors

Calretinin has been proposed as a novel marker of ovarian sex cord-stromal tumors (SCST); this study aims to determine whether calretinin can complement or supplant the established utility of inhibin in the differential diagnosis of SCST. WT1 has been shown to be expressed in ovarian serous, but not mucinous neoplasms; its expression in a variety of ovarian tumors is also examined. Formalin-fixed, paraffin-embedded archival tissues from 111 primary ovarian tumors were analyzed with commercially available antibodies using semi-automated immunohistochemistry. Results were graded on a 4-tiered scale with staining of more than 0 but less than 5% of cells considered focal. Of 27 SCST, 56% were calretinin and 56% inhibin positive overall; 90% of granulosa cell tumors, 57% of Sertoli-Leydig cell tumors, 33% of thecomas, and 14% of fibromas were calretinin positive. Inhibin was expressed in 60% of granulosa cell tumors, 71% of Sertoli-Leydig cell tumors, 43% of fibromas, and 33% of thecomas. Of 35 surface epithelial tumors (SET), 8% of serous papillary tumors were calretinin positive, whereas 8% of serous papillary tumors and 13% of poorly differentiated carcinomas expressed inhibin. WT1 was expressed in 29% of all endometrioid carcinomas, 10% of borderline mucinous tumors, and no mucinous carcinomas; however, most of the other SETs were positive (77% serous papillary and 88% poorly differentiated carcinomas). Among the SCST, WT1 stained only granulosa cell tumors (75%), though often weakly or variably. Calretinin has only slightly greater sensitivity (76% versus 65%) and equal specificity to inhibin (92%) in the differential staining of granulosa or Sertoli-Leydig cell tumors, that is, nonstromal SCST. Hence, calretinin cannot replace but could complement inhibin as part of an immunohistochemical panel used for diagnostically challenging SCST. Although WT1 should be reliably positive in non-mucinous SET, staining of granulosa cell tumors and lack of expression in a sizable subset of endometrioid carcinomas may confound interpretation.

Monosomy 22 as a diagnostic aid in a case of late recurrence of adult granulosa cell tumor of the ovary

Cytogenetic analysis of a case of metastatic granulosa cell tumor recurring 21 years after oophorectomy revealed monosomy 22. This anomaly, typical of granulosa cell tumor, coupled with the pathologic and immunophenotypic findings assisted in establishing the proper diagnosis of this lesion in the absence of the original histopathologic slides.

Inhibins and activins in pregnancy

Human placenta, decidua, and fetal membranes are the major sites of production and secretion of inhibin A and activin A in maternal serum, amniotic fluid, and umbilical cord blood. These tissues also express follistatin-related gene and betaglycan, the binding proteins of activin A and inhibin A, respectively, recently identified. They show a different expression throughout pregnancy, suggesting new functional roles into gestational tissues. The availability of suitable assays for measuring inhibin A and activin A lead us the possibility to investigate their secretion in healthy pregnancy. In addition, several evidences underline the potential role and the clinical usefulness of their measurement in the diagnosis, prevention, prognosis and follow-up of different gestational pathologies such as: threatened abortion, placental tumors, hypertensive disorders of pregnancy, intrauterine growth restriction, fetal hypoxia. The measurement of inhibin A and activin A into the biological fluids of pregnancy will offer in the future further possibilities in early diagnosis, prediction, and monitoring pregnancy diseases.

Inhibin Expression in Ovarian-type Stroma in Mucinous Cystic Neoplasms of the Pancreas

Mucinous cystic neoplasms (MCNs) of the pancreas are typically found in middle-aged to elderly women and contain ovarian-type stroma in the cyst wall. Whether the resemblance of this stroma to ovarian stroma is only morphologic or has more functional similarity is still unclear. Estrogen receptors (ER) and progesterone receptors (PR) have been shown to be expressed in a wide variety of tissues and tumors, including the ovarian-type stroma of MCN. Inhibin, on the other hand, has been shown to have a more restricted expression, limited to ovarian sex cord-stromal components and placental cells, and has recently been shown to be expressed in pancreatic MCNs. However, it is still unclear whether this expression is limited to MCNs of the pancreas and whether it has any diagnostic role. Seven cases of MCN (4 mucinous cystadenoma, 2 borderline MCN, and 1 mucinous cystadenocarcinoma with microinvasion), 6 cases of intraductal papillary mucinous tumor, 1 of mucinous cystic tumor of uncertain classification, 2 of mucinous noncystic adenocarcinoma, 4 of serous cystadenoma, and 4 solid pseudopapillary neoplasms were selected for this study. Five cases with normal pancreatic tissue were included as controls. Immunohistochemical stains for alpha-inhibin, ER, and PR were performed on a representative section from each case on formalin-fixed, paraffin-embedded tissue sections using a standard indirect immunoperoxidase method. All cases of MCN were in female patients with an average age of 55.3 years, showing ovarian-type stroma and clusters of alpha-inhibin-positive luteinized theca-like cells. In all these cases, moderate to strong PR positivity was also noted in the ovarian-type stroma, including many of the alpha-inhibin-positive luteinized theca-like cells. ER was expressed in 2 cases. The epithelial cells of MCNs were all negative for ER, PR, and alpha-inhibin staining. Of the other tumors, 4 solid pseudopapillary neoplasms showed positivity for only PR in the tumor cells. The remaining tumors were negative for all markers. In conclusion, the finding of alpha-inhibin positivity in MCN with ovarian-type stroma further supports its similarity to true ovarian stromal tissue and may suggest a role of complex hormonal interaction in the pathogenesis. In addition, its limited expression in MCNs of the pancreas may be diagnostically useful in difficult cases.

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.

Serous cystic neoplasms of the pancreas: an immunohistochemical analysis revealing alpha-inhibin, neuron-specific enolase, and MUC6 as new markers

Serous cystic neoplasms (SCNs) of the pancreas include serous microcystic adenoma (SMA), serous oligocystic ill-demarcated adenoma (SOIA), solid serous adenoma (SSA), von Hippel-Lindau-associated cystic neoplasm (VHL-CN), and serous cystadenocarcinoma (SCC). These neoplasms are histologically similar but differ in their localization, gross appearance, gender distribution, and biology. A centroacinar origin is assumed but has not been proven. To clarify whether the various subtypes of SCN may be distinguished from each other by marker profiles that might also provide evidence of their origin, the immunoprofiles of 38 SCNs (21 SMAs, 13 SOIAs, 2 VHL-CNs, 1 SSA, and 1 SCC) were defined by applying antibodies against cytoskeletal, neuroendocrine, hormone receptor, and mucin markers. In addition, we examined the expression of calretinin and alpha-inhibin. The various types of SCN showed a very similar immunoprofile, characterized by positivity for cytokeratins and neuron-specific enolase and negativity for vimentin and synaptophysin. Further markers that were commonly expressed in SCNs were alpha-inhibin (SMAs: 76%, SOIAs: 92%, VHL-CNs: 100%), MUC6 (SMAs: 60%, SOIAs: 85%, VHL-CNs: 100%), and MUC1 (SMAs: 24%, SOIAs: 38%, VHL-CNs: 50%). Western blot analysis in one SMA revealed a distinct band that stained with neuron-specific enolase antiserum. Alpha-inhibin was only expressed in 4 of 11 acinar cell carcinomas and not in five ductal adenocarcinomas, five neuroendocrine tumors, one mixed ductal-endocrine carcinoma, and one acinar cell cystadenoma of the pancreas. These results suggest that, despite their biologic differences, the various types of SCNs are composed of the same (or a very similar) cell type and may therefore have a common direction of differentiation. This notion is further supported by the finding that neuron-specific enolase, alpha-inhibin, and MUC6, which may be regarded as new markers for this pancreatic tumor type, were also expressed in most SCNs. Because a number of SCNs share MUC1 and MUC6 expression with the pancreatic centroacinar cells, the possibility of a histogenetic relationship has to be considered.

Immunohistochemistry in gynaecological pathology: a review

This paper reviews some aspects of the application of immunohistochemistry in gynaecological pathology. The use of cytokeratins 7 and 20 are discussed with reference to applications in ovarian pathology, including metastatic disease to the ovaries. Developments in utilising MIB-1 and p16 in cervical squamous and glandular lesions are discussed. Recent assertions regarding the differential diagnosis between endocervical and endometrial carcinomas are also reviewed. Antibodies that may be of use in the diagnosis of uterine mesenchymal and ovarian tumours are highlighted, as are antibodies of use in trophoblastic lesions including the use of p57 in evaluating hydatidiform moles.

Non-neoplastic granulosa cells within ovarian vascular channels: a rare potential diagnostic pitfall

AIMS

To describe six cases seen in consultation in which artefactual vascular involvement within the ovary by benign granulosa cells caused diagnostic confusion.

METHODS/RESULTS

In five cases, the initial favoured diagnoses of the submitting pathologists were metastatic carcinoma (three cases) and immature neural elements within a teratoma (two cases). In two cases, the ovary contained a benign cystic teratoma (one with struma ovarii), in two cases endometriosis, in one case follicular cysts, and in the other no pathological lesion was present. In all cases, several small ovarian vascular channels contained cohesive groups of cells with mildly atypical nuclei and cytoplasm, which varied from scant to abundant and eosinophilic. In four cases, mitotic figures were identified. The cells were morphologically consistent with benign granulosa cells and were associated in four cases with a nearby follicle lined by similar cells. There was no evidence of a mass lesion, grossly or histologically, to suggest a granulosa cell tumour. The nature of the cells was confirmed using immunohistochemistry for alpha inhibin and calretinin in one case.

CONCLUSIONS

This phenomenon is probably an artefact secondary to surgical trauma or sectioning within the laboratory; alternatively, it could be related to ovulation. It is important that this benign process is not misinterpreted as cancer, either primary or metastatic, which may prompt inappropriate treatment or investigations that are not needed.

Follicular expression of c-Kit/SCF and inhibin-alpha in mouse ovary during development

The mechanism of development of the ovarian follicles has been largely unknown. We performed an immunohistochemical (IHC) study to determine the follicular expressions of c-kit, SCF, and inhibin-alpha at different developmental stages in mouse ovary. Ovaries were obtained from 14 and 16 days post coitum and 2, 7, and 21 days post partum (dpp) mice. IHC for c-kit, SCF, and inhibin-alpha was carried out. c-Kit and SCF were expressed on oogonia regardless of the developmental stage. Immunoreactive c-kit and SCF antigens were expressed on oocytes of primordial and primary follicles of neonate mouse ovaries. In 21 dpp mouse ovary, the expression of c-kit/SCF in oocytes gradually decreased as the follicles developed. c-Kit/SCF was expressed strongly in oocytes of preantral follicles and weakly in granulosa and thecal cells. Inhibin-alpha was mainly expressed on granulosa cells of preantral and early antral follicles of the 21 dpp mouse ovaries. These findings suggest that the IHC expression of c-kit/SCF proteins is specific in all developmental stages of ovarian follicles and is decreased after the follicle starts to grow. The expression of inhibin-alpha is negatively correlated with the expression of c-kit/SCF in the ovarian follicles in mice.

Applications of monoclonal anti-human inhibin alpha subunit in endometrial curettings

AIMS

Using archival material, we studied the immunoreactivity and utility of monoclonal anti-human inhibin alpha subunit in the identification of chorionic villi (CV) and trophoblastic subpopulations in endometrial curettings (EC) from patients who had intra-uterine, ectopic, molar and, particularly, probable intra-uterine pregnancies. We also compared its expression with those of betaHCG, HPL and CAM 5.2.

METHODS

The four groups of EC investigated included: Group 1, 15 patients with intra-uterine pregnancies (IUP); Group 2, 15 patients with tubal pregnancies (TP); Group 3, 15 patients with hydatidiform moles (HM); and Group 4, 20 patients with purported history of intra-uterine pregnancies (PIUP). Positive and negative control cases were from Groups 1 and 3 and Group 2, respectively. The test cases were from Group 4. Immunohistochemistry was performed on each case testing for expression of inhibin alpha, betaHCG, HPL and CAM 5.2.

RESULTS

Trophoblastic populations, which included syncytiotrophoblast (ST), cytotrophoblast (CT) and intermediate trophoblast (IT), were absent in all 15 negative control cases (Group 2). The 30 positive control cases (Groups 1 and 3) revealed the following: (a) ST, CT and IT were identified in all cases and were positive for CAM 5.2, (b) inhibin alpha, betaHCG and HPL (except one case) were reactive for all cases with ST, but not CT, and (c) IT positivity for betaHCG, HPL and inhibin alpha was 67, 80-93 and 100%, respectively. From the 20 test cases (Group 4), the findings were: (a) CT was absent in all cases, (b) scattered ST cells, which were identified only in 10 cases, were positive for all antibodies, (c) scattered IT cells were present in 17 cases and showed 100% CAM 5.2 positivity, and (d) IT positivity for betaHCG, inhibin alpha and HPL was 58.8% (10/17), 76.5% (13/17) and 82.4% (14/17), respectively. Background staining was observed in 22 of 65 cases (33.8%) stained with betaHCG and HPL; half of these cases came from Group 3. Inhibin alpha and CAM 5.2 staining did not show this problem.

CONCLUSIONS

We suggest that inhibin alpha is a useful antibody in diagnosing IUP and HM and in documenting intra-uterine gestations in cases with PIUP because it is a sensitive marker in immunolabelling IT and ST. Combined application of inhibin alpha and CAM 5.2 might be more useful than betaHCG and HPL because the latter showed background staining in one third of the cases.

Melan-A (A103) and inhibin expression in ovarian neoplasms

A103 is a melanocyte-associated monoclonal antibody that recognizes the Melan-A/MART-1 antigen in melanomas. The Melan-A/MART-1 antigen is also expressed in Leydig cells, adrenal tissue, and steroid-secreting tumors. A103 immunoreactivity in ovarian neoplasms, specifically sex cord stromal tumors (SCSTs), has not been well studied. Inhibin is known to be expressed in SCSTs but is also expressed in some carcinomas and other tumors. We sought to explore the usefulness of both antibodies in the diagnosis of ovarian neoplasms. Using conventional tissue sections and a tissue microarray, we studied the immunoreactivities of 131 ovarian tumors for A103 and inhibin: 30 SCSTs, including fibrothecoma, luteoma, hilus cell tumor, granulosa cell tumor, Sertoli-Leydig cell tumor, and sex cord tumor with annular tubules, and a control group of 96 surface epithelial tumors. A few other rare ovarian tumors including 1 small cell carcinoma, 1 adenocarcinoid tumor, 1 ovarian tumor of probable wolffian origin, 1 Krukenberg tumor, and 1 desmoplastic small round cell tumor were also studied. Inhibin staining was generally strong and diffuse in the majority of SCSTs (83%) and at least focally positive in the small cell carcinoma, ovarian tumor of probable wolffian origin, Krukenberg tumor, and desmoplastic small round cell tumor. Variable immunoreactivities were also present in 7 of 96 (7.3%) surface epithelial tumors. In comparison, A103 expression was usually weaker and more focal than that of inhibin and was present in a smaller proportion of SCSTs (37%) and negative in all the surface epithelial tumors. A103 was typically positive in the lipid-containing cells (both neoplastic and normal components) of these tumors (fibrothecomas, luteomas, Sertoli-Leydig cell tumors, hilus cell tumors, and granulosa cell tumors), and in some cases, moderate positivity was noted in these cells. Weak A103 positivity was identified in the single case of ovarian tumor of probable wolffian origin. A103 is relatively less sensitive than inhibin for recognizing SCSTs but does not appear to be expressed by ovarian surface epithelial tumors. It is therefore more specific than inhibin for SCSTs and is a useful marker for specifically identifying lipid-containing cells in tumors. Thus, adding A103 to a panel of markers including inhibin may be a valuable adjunct in the differential diagnoses of SCSTs and their distinction from other ovarian neoplasms.

Uterine tumor resembling ovarian sex-cord tumor: report of a case mimicking cervical adenocarcinoma

Uterine tumors resembling ovarian sex-cord tumors (UTROSCTs) are unusual neoplasms with histologic features that resemble those within ovarian Sertoli and granulosa cell tumors. We report the case of a 24-year-old woman with a UTROSCT presenting as a cervical mass, which on initial evaluation was thought to represent cervical adenocarcinoma. The patient's cervical biopsy specimen contained epithelioid cells arranged in tubules and anastomosing cords, without significant cellular atypia or mitotic activity. Because this morphology elicited a broad differential diagnosis, immunohistochemical studies were performed. The tumor was found to be diffusely positive for cytokeratin cocktail, calretinin, and desmin, focally positive for CK7 and SMA, and negative for EMA, CEA, inhibin, CD10, CK20, chromogranin, and synaptophysin. Ultrastructural examination revealed occasional gland-like lumens with cells joined by desmosomes and a continuous basal lamina. UTROSCTs have features that may cause them to be confused with more common tumors, especially in limited biopsy samples, and should be included in the differential diagnosis when a gland-forming neoplasm with an unusual appearance is identified in a cervical or endometrial biopsy specimen.

Granulosa cell tumor of the ovary

Adult granulosa cell tumor (GCT) of the ovary is oftentimes a hormonally active, stromal cell neoplasm that is distinguished by its ability to secrete sex steroids such as estrogen. Patients may present with vaginal bleeding caused by endometrial hyperplasia or uterine cancer as a result of prolonged exposure to tumor-derived estrogen. In addition, GCT is a vascular tumor that may occasionally rupture and result in abdominal pain, hemoperitoneum, and hypotension, mimicking an ectopic pregnancy in younger patients. GCT is usually associated with a mass on pelvic examination that is subsequently confirmed on ultrasonography. Surgery is required for definitive tissue diagnosis, staging, and tumor debulking. In older women, a total abdominal hysterectomy and bilateral salpingooophorectomy are typically performed. In women of childbearing age, a more conservative unilateral salpingo-oophorectomy may be performed, assuming that careful staging reveals that the disease has not extended outside of the involved ovary and that a concomitant uterine cancer has been excluded. Survival of patients with GCT is generally excellent because most patients present with early-stage disease, although certain high-risk patient groups may be identified. Stage is the most important prognostic factor, with a higher risk of relapse being associated with stages II through IV disease. In addition, patients with stage I disease associated with features such as large tumor size, high mitotic index, or tumor rupture may also be at higher risk in some series. The value of postoperative adjuvant therapy for high-risk patients has not been investigated by prospective randomized trials, which are difficult to perform because of the rarity of this tumor. Nonetheless, the use of adjuvant chemotherapy or radiation has sometimes been associated with prolonged disease-free survival in patients with high-risk features. Because of the propensity of GCT to recur years after initial diagnosis, prolonged surveillance with serial physical examination and serum tumor markers such as estradiol and inhibin is reasonable.

Inhibin is more specific than calretinin as an immunohistochemical marker for differentiating sarcomatoid granulosa cell tumour of the ovary from other spindle cell neoplasms

AIMS

To describe a case of recurrent sarcomatoid adult granulosa cell tumour (AGCT) of the ovary and to evaluate the usefulness of two ovarian sex cord stromal markers (inhibin and calretinin) in separating sarcomatoid AGCT from true sarcomas.

METHODS

A 72 year old woman presented with a recurrent sarcomatoid AGCT in the sigmoid colon mesentery, which histologically mimicked a malignant gastrointestinal stromal tumour (GIST). This index case and 79 sarcomas (32 GISTs, 28 leiomyosarcomas, 15 endometrial stromal sarcomas (ESSs), including one with sex cord-like areas, and four undifferentiated uterine sarcomas) were immunostained using antibodies to inhibin and calretinin.

RESULTS

The recurrent sarcomatoid AGCT expressed diffuse, strong cytoplasmic immunoreactivity with inhibin and focal but strong nuclear and cytoplasmic positivity with calretinin. Focal, weak cytoplasmic inhibin expression limited to sex cord-like areas was present in one ESS. None of the other sarcomas expressed inhibin. Focal, strong calretinin immunoreactivity was identified in 11 leiomyosarcomas and one GIST. The case of ESS with sex cord-like areas showed strong immunoreactivity for calretinin limited to the sex cord-like areas.

CONCLUSIONS

Inhibin is a useful immunomarker to distinguish sarcomatoid AGCT from other spindle cell neoplasms that may enter into the differential diagnosis. Calretinin appears to be less specific than inhibin.

Update on granulosa cell tumours of the ovary

PURPOSE OF REVIEW

Granulosa cell tumours of the ovary are an uncommon ovarian sex-cord stromal tumour. These neoplasms provide a spectrum of clinical presentations that span from the first to the tenth decade. Surgery represents the primary therapy for early stage disease; however, management of women with advanced disease is less clear. Because of their relative rarity, evidence to support decision-making in the management of granulosa cell tumours is limited. The purpose of this review is to provide the clinician with an updated knowledge of the clinical and molecular aspects of granulosa cell tumours in order to guide therapy.

RECENT FINDINGS

The clinical stage, mitotic index and cellular atypia correlate most strongly with prognosis. However, these tumours may demonstrate heterogeneous genetic aberrations that can predict behaviour and response to therapy. Case series and reports suggest that postoperative combination chemotherapy is of most benefit in advanced disease. Serial measurements of serum inhibin may be helpful in the follow-up of these women, particularly in the post-menopausal group.

SUMMARY

The pathology and treatment of women with granulosa cell tumours of the ovary is complex. Such women should be managed in a multidisciplinary gynaecological oncology unit. A better understanding of the molecular pathology may assist treatment.

Malignant granulosa-theca cell tumor in a two-year-old Miniature Horse

A 2-year-old female Miniature Horse that presented with a history of progressive weight loss, depression, and diarrhea was diagnosed at necropsy with a highly malignant abdominal neoplasm involving the left ovary, kidneys, adrenal glands, intestines, and various abdominal and thoracic lymph nodes. Microscopic examination of these masses revealed large pleomorphic cells that stained positive for vimentin and inhibin and negative for epithelial membrane antigen and placental alkaline phosphatase. Ultrastructural examination of the cells revealed a high nucleocytoplasmic ratio and indented euchromatic nuclei with large nucleoli. Based on the gross, microscopic, immunohistochemical, and ultrastructural features, the neoplasm was identified as a malignant granulosa-theca cell tumor, a rare neoplasm in young horses.

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.

Retiform Sertoli-Leydig cell tumours: clinical, morphological and immunohistochemical findings

AIMS

To determine the morphological and immunohistochemical profile of retiform Sertoli-Leydig cell tumours and to compare the observed profile with that of adult rete ovarii.

METHODS AND RESULTS

Nineteen retiform Sertoli-Leydig cell tumours were studied, eight by immunohistochemistry, and five examples of rete ovarii from adult females were also evaluated immunohistochemically. The patients ranged in age from 3 to 74 years with a mean age of 31 years. Four patients were virilized and had an abdominal mass; two were virilized with amenorrhoea and two had amenorrhoea alone. Eight presented with an abdominal mass and one patient was pregnant. Two tumours were incidental findings. Information on stage was available in 16 patients: 14 tumours were stage 1, one was stage 2, and one was stage 3. Fifteen tumours were of intermediate differentiation and four were poorly differentiated. Papillary structures were evident grossly in four cases. Microscopically, all cases had a retiform pattern in addition to varying quantities of sex cord, gonadal stromal and heterologous elements. Heterologous elements were present in 13 cases and consisted of hepatocytes (n = 7), mucinous epithelium (n = 7) and skeletal muscle (n = 2). Immunohistochemical evaluation of eight tumours showed a more intense positivity for keratin in the retiform areas, whereas the gonadal stromal component had a more intense expression of inhibin. Inhibin stains Leydig cells strongly and hepatocytes moderately. Rete ovarii epithelium was positive for keratin and vimentin in the five cases studied, and for inhibin in one case. Follow-up was available on 13 patients. Three tumours behaved in a malignant fashion: one each was stage 1, 2, and 3 at diagnosis.

CONCLUSIONS

Immunohistochemistry is useful in distinguishing retiform Sertoli-Leydig cell tumours from other tumours that they may resemble. Inclusion of inhibin is essential in a panel of antibodies to evaluate these tumours. The clinical behaviour of these neoplasms cannot always be predicted from their morphology or clinical stage.

Serum activin A and inhibin A. New clinical markers for hydatidiform mole

BACKGROUND

Although human placenta is a well established, rich source of proteins, hCG is the only measurement available to date in diagnosing the occurrence of the hydatidiform mole. Serum levels of a new placental protein, immunoreactive inhibin, were high in molar pregnancy, but the inhibin assay never became of clinical use, due to its low specificity and reliability. Since specific assays are now available for inhibin A, inhibin B, and activin A, the current study evaluated whether and which of these placental proteins is increased in presence of a molar pregnancy.

METHODS

Serum inhibin A, inhibin B, activin A, and hCG levels were assayed in: A) 6 women with molar pregnancies, before and after evacuation; B) 37 healthy pregnant women; and C) 22 healthy nonpregnant women.

RESULTS

Women with partial hydatidiform moles had significantly higher serum levels of inhibin A (P < 0.001) and activin A (P < 0.001) than healthy pregnant women, several fold higher than the 95% confidence interval of control values. After evacuation, the levels of both inhibin A (P < 0.001) and activin A (P < 0.05) declined significantly to the levels of nonpregnant controls. Molar hCG concentrations were significantly higher than in normal pregnancy (P < 0.001), but some values within the 95% confidence interval of normal values. Despite a significant decrease (P < 0.05) after evacuation, hCG levels were still higher than in nonpregnant women.

CONCLUSIONS

The present data strongly suggest that serum inhibin A and activin A measurement may be of value in diagnosis and short-term follow-up of molar pregnancy.