Inhibin immunohistochemistry applied to ovarian neoplasms: a novel, effective, diagnostic tool

Ovarian Sex Cord Stromal Tumor in a Free-Ranging Brown Bear (Ursus arctos)

Reports on neoplasms in bears are scarce, especially concerning ovarian tumors. A large primary ovarian neoplasm with multiple metastasis was found during the necropsy of a 14-year-old free-ranging Eurasian brown bear (Ursus arctos) from Northwestern Spain. Histopathology and immunohistochemistry allowed for the diagnosis of a sex cord stromal tumor. This is a complex group of neoplasms which differ in the predominant cell morphology and immunohistochemical features. The microscopic examination revealed two types of cells, one with eosinophilic cytoplasm, intermingled with larger vacuolated cells rich in lipids. The evaluation of the immunoreactivity to different markers, frequently used in the characterization of gonadal tumors (INHA, inhibin-alpha; PLAP, placental alkaline phosphatase; Ki-67; α-SMA, actin alpha-smooth muscle) and inflammation patterns (IBA1, ionized calcium-binding adapter molecule for macrophages; CD3 for T lymphocytes; CD20 for B lymphocytes), displayed significant INHA positive immunostaining of neoplastic cells, as well as inflammatory cell infiltration, mainly composed of macrophages and B lymphocytes. These findings were consistent with a malignant ovarian steroid cell tumor, not otherwise specified. The present study characterizes an unusual type of neoplasm, and also represents the first report of an ovarian sex cord stromal tumor in Ursidae.

Sclerosis in Sex Cord-Stromal Tumors Other Than the Sclerosing Stromal Tumor: A Report of 70 Cases

Sclerosis is well-known in sclerosing stromal tumors (SSTs), as its name indicates, but has not been evaluated in other ovarian sex cord-stromal tumors (SCSTs). Its presence in other SCSTs has sporadically caused diagnostic problems in cases we have seen, and this prompted us to review SCSTs with appreciable sclerosis; tumors containing at least 20% sclerosis were included. Seventy cases were identified: 20 thecomas, 20 juvenile granulosa cell tumors (JGCTs), 8 adult granulosa cell tumors (AGCTs), 5 sex cord tumors with annular tubules, 6 retiform Sertoli-Leydig cell tumors (SLCTs; all of the intermediate differentiation), 4 nonretiform SLCTs (3 well-differentiated, 1 of intermediate differentiation with heterologous elements), 4 Sertoli cell tumors, and 3 microcystic stromal tumors (MSTs). Paucicellular sclerotic zones comprised 20% to 95% of the tumors and when conspicuous often obscured diagnostic features. Thirty-one tumors (10 thecomas, 19 JGCTs, 1 AGCT, and 1 MST) showed sclerotic zones focally enveloping nodules of tumor cells, imparting a pseudolobular appearance, and sclerosis often occurred within lobules as well. Ten of these (5 thecomas and 5 JGCTs) also had prominent staghorn blood vessels, generating a low-power appearance focally similar to SST. In 17 tumors, the sclerosis resulted in "compression" of the tumor cells into cords and/or solid tubules. Correct diagnosis in these cases is dependent on careful examination of the cellular zones of the neoplasms, but awareness of the extent of sclerosis that may be seen in diverse SCSTs may be crucial in suggesting the correct diagnosis particularly when the material is limited as in the intraoperative setting. Our findings highlight for the first time the occurrence and character of sclerosis in sex cord tumors other than SSTs and fibromas. Sclerosis is seen in descending proportion of the tumor types as follows: retiform SLCTs, thecomas, MSTs, JGCTs, sex cord tumors with annular tubules, Sertoli cell tumors, AGCTs, and nonretiform SLCTs. Its character can vary somewhat, having particular features in the sex cord tumor with annular tubules (hyaline material within tubules often coalescing and extending beyond the nests to form confluent aggregates) and retiform SLCTs (common in papillary cores).

A clinicopathological study of granulosa cell tumors of the ovary: Can morphology predict prognosis?

Objective

Granulosa cell tumors (GCT) are low-grade malignant sex cord-stromal tumors (SCST) with late metastasis/recurrences and long disease-free periods. We performed a clinicopathological evaluation of GCT to ascertain features having prognostic impact.

Materials and Methods

All cases of GCT of ovary from January 2006 to December 2018 were assessed for architectural patterns, nuclear grooves, and Call-Exner bodies. Each feature was graded on frequency of occurrence: not present (0)-very frequent (3). Anisonucleosis, necrosis, and inflammation were noted. Cases were grouped on mitotic count; <10 mitosis/10 High power field (HPF) or >=11 mitoses/10 HPF and Ki-67 index; <10% Ki-67 and >=11% Ki-67.

Results

GCT formed 60.1% of SCST. Sixty cases' ages were in the range of 15-78 years (median 45). Clinical details were available in 37. Commonest presentation was abnormal uterine bleeding. Serum CA125 was raised in 16.1% and Inhibin in 58.8%. Seventy percent were in stage I. Disease recurrence was associated with higher stage (P = 0.007). The most frequent pattern was diffuse sheets (47%). Call-Exner bodies were absent in 22.2%. Grooves with score 1, 2, and 3 were seen in 35.8%, 23.5%, and 13.6%, respectively. Anisonucleosis was present in 26.7%, necrosis in 11.1%, and lympho-plasmacytic infiltrate in 43%. Out of total, 93.3% had <10 mitosis/10 HPF and 43.2% had recurrence, most with high Ki-67 (P = 0.064).

Conclusion

Our study outlines histomorphological spectrum of GCT and emphasizes its frequent occurrence in lower stages with late recurrences. The presence of grooves may indicate granulosa-cell origin. Call-Exner bodies are not a necessity. Histomorphological features are not prognostically important. However, prognostic value of Ki-67 cannot be excluded. Limitation of the study was a small number of cases with follow-up.

DICER1 and FOXL2 Mutation Status Correlates With Clinicopathologic Features in Ovarian Sertoli-Leydig Cell Tumors

Sertoli-Leydig cell tumors (SLCTs) are rare ovarian sex cord-stromal neoplasms. The only known recurrent genetic abnormality is DICER1 mutation, with rare mutations reported in FOXL2. We set out to establish a molecular classifier using DICER1 and FOXL2 somatic mutation status and clinicopathologic features in 42 SLCTs. Five tumors (12%) were well differentiated, 31 (74%) moderately differentiated, and 6 (14%) poorly differentiated. Eight (19%) had heterologous elements, and 2 (5%) showed retiform differentiation; all 10 were moderately differentiated. DICER1 RNase IIIb domain mutations were identified in 18/41 (44%; 17 moderately, 1 poorly differentiated), including all cases with retiform or heterologous elements. FOXL2 c.402C>G (p.C134W) mutation was identified in 8/42 (19%) tumors (5 moderately, 3 poorly differentiated). DICER1 and FOXL2 mutations were mutually exclusive. Median age for the cohort was 47 years (range, 15 to 90 y). Patients with DICER1 mutations were younger (median, 24.5 y; range, 15 to 62 y) than patients with FOXL2 mutation (median, 79.5 y; range, 51 to 90 y) (P<0.0001). Nine of 10 tumors with retiform or heterologous elements occurred in premenopausal patients (median, 26.5 y; range, 15 to 57 y). Patients with tumors that were wild type for DICER1 and FOXL2 (15/42, 37%) had an intermediate age (median, 51 y; range, 17 to 74 y). All tumors were FOXL2 positive by immunohistochemistry. Patients with FOXL2 mutation trended toward presenting more often with abnormal bleeding (P=0.13); DICER1-mutant patients trended toward having more androgenic symptoms (P=0.22). Our data suggest at least 3 molecular subtypes of SLCT with distinct clinicopathologic features: DICER1 mutant (younger, more androgenic symptoms, moderately/poorly differentiated, retiform or heterologous elements), FOXL2 mutant (postmenopausal, abnormal bleeding, moderately/poorly differentiated, no retiform or heterologous elements), and DICER1/FOXL2 wild type (intermediate age, no retiform or heterologous elements, including all well-differentiated tumors).

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 disparate origins of ovarian cancers: pathogenesis and prevention strategies

Ovarian cancer is the fifth cause of cancer-related death in women and comprises a histologically and genetically broad range of tumours, including those of epithelial, sex cord-stromal and germ cell origin. Recent evidence indicates that high-grade serous ovarian carcinoma, clear cell carcinoma and endometrioid carcinoma primarily arise from tissues that are not normally present in the ovary. These histogenetic pathways are informing risk-reduction strategies for the prevention of ovarian and ovary-associated cancers and have highlighted the importance of the seemingly unique ovarian microenvironment.

Malignant undifferentiated sex cord-stromal testis tumor with brain metastasis: case report

Metastatic undifferentiated sex cord-stromal testis tumors are uncommon. We would like to present a rare case of undifferentiated sex cord-stromal testis tumor with brain metastasis. After presenting with a painless right testicular mass, the patient underwent right radical orchiectomy and retroperitoneal lymph node dissection. One month later, the patient had no visible evidence of tumor recurrence on the follow-up computed tomography of the chest, abdomen, and pelvis. Three months after the first follow-up, the patient was readmitted for new onset of shortness of breath, and 7th and 12th cranial nerve palsy. Computed tomography of the chest and magnetic resonance imaging of the brain showed evidence of distant metastasis. To our knowledge, undifferentiated sex cord-stromal tumor with brain metastasis has not been reported. As with any new onset neurologic deficits in patients with solid tumors, the presence of brain metastases should be considered.

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.

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.

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.

Prognostic factors of ovarian granulosa cell tumor: a study of 35 patients and review of the literature

Ovarian granulosa cell tumors (GCT) are rare tumors with a tendency of late relapse and good prognosis. FIGO stage, tumor size, degree of cellular atypia, and mitotic index have been reported to predict recurrence. The objective of this study is to evaluate treatment practice and prognostic factors of GCT. For this purpose, a detailed review of patient files and histopathologic evaluation of tumor samples, including estimation of growth pattern, presence of Call-Exner bodies, nuclear atypia, mitotic index, and immunohistochemical staining for inhibin and Ki-67 were analyzed. Thirty-five patients had histologically confirmed GCT. Four patients had a simultaneous endometrial adenocarcinoma. Median follow-up time was 135 months (range 19-334 months). Recurrent disease was detected in seven patients. Time from diagnosis to the first recurrence varied from 24 to 141 months. There was no difference in tumor size, nuclear atypia, mitotic index, presence of Call-Exner bodies, or Ki-67 staining between nonrecurred and recurred patients. The only factor associated with risk of recurrence was rupture of the tumor (P < 0.0001), and the only factor associated with overall survival was FIGO stage (P = 0.032). The disease-free and overall survivals were not statistically different between patients treated (N = 18) or not treated (N = 17) with adjuvant therapy. One patient has experienced seven recurrences, has been treated with surgery, radiation therapy, chemotherapy, and hormonal therapy, and is still alive 26 years from diagnosis. FIGO stage and tumor rupture were the only factors associated with the outcome of GCT. Treatment of relapse, even in case of multiple recurrences, is usually worthwhile.

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.

[Isolated metastasis of the granulosa cell tumor of the ovary in the small intestine mesentery 19 years after salpingo-oophorectomy]

INTRODUCTION

Granulosa cell tumour is uncommon malignant tumor which belongs to the sexual cord-stromal tumors of the ovary. It arises from the specialized stromal cells of the ovary. These tumors are unilateral in 95%. Over 90% of patients survive more than 10 years after surgery, but the recurrence may appear even 25 years after surgery.

CASE REPORT

The authors present a 54-year-old woman who was admitted for abdominal pain and ultrasonography revealed tumor in the abdomen. During the surgery, a spheric, well circumscribed tumor of the mesentery, close to the forth portion of duodenum, was excised. Histological and immunohistochemical examinations verified that it was the metastasis of the granulosa cell tumor of the ovary that had been removed 19 years ago when salpingo-oophorectomy had been performed. Postoperative recovery was uneventful. Twenty six months later, the tumor 4 cm in diameter recurred, and was localized to the left of duodenum, close to the inferior mesenteric artery, which was perfectly ideally, together with fat tissue and surrounding lymph nodes. She has remained symptom free so far.

CONCLUSION

To the best of our knowledge, this is the first case of the isolated metastasis of the granulosa cell tumor in the mesentery, that appeared 19 years after original surgery.

Use of novel serum markers in clinical follow-up of Sertoli-Leydig cell tumours

BACKGROUND

Sertoli-Leydig cell tumours of the ovary account for only 0.2% of malignant ovarian tumours. Two-thirds of all patients become apparent due to the tumour's hormone production.

METHODS

A 41-year-old patient (gravida 4, para 4) presented with dyspnoea, enlarged abdominal girth and melaena. Diagnostic imaging was suspicious for an ovarian cancer. The standard tumour marker for ovarian cancer (CA 125) was elevated to 984 U/mL.

RESULTS

Surgical exploration of the abdomen revealed a mouldering tumour of both adnexes extending to the level of the navel. Frozen sections showed an undifferentiated carcinoma of unknown origin. Radical surgery was performed. The final histological report described a malignant sex-cord stroma tumour, a Sertoli-Leydig cell tumour, emanating from both ovaries. Analysis of preoperative blood serum showed elevated levels of CYFRA 21-1 (10.4 ng/mL), neuron-specific enolase (36.2 ng/mL), oestradiol (485 pg/mL) and CA-125 (984 U/mL). Adjuvant chemotherapy and regional hyperthermia were performed due to the malignant potential and incomplete resection of the tumour.

CONCLUSIONS

Undifferentiated Sertoli-Leydig cell tumours show a poor clinical course. As only two-thirds of patients with this rare disease present with elevated hormone levels, new markers deserve further investigation to offer more specific, individualised tumour monitoring.

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.

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.

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.

Pediatric sex cord-stromal tumor with composite morphology: a case report

A 12-year-old female with developmental delay/mental retardation and a family history of gynecologic cancers presented with nonspecific abdominal complaints and was found to have a 4.5-kg, 25- x 23- x 15-cm pelvic mass with solid and cystic components and associated retroperitoneal and mesenteric lymphadenopathy. Laboratory studies revealed increased serum levels of CA-125 and inhibin B. Histologically, the tumor exhibited several different morphologic appearances including adult granulosa cell tumor, juvenile granulosa cell tumor (with areas of marked atypia), and Sertoli cell tumor. Immunohistochemically, the tumor was positive for calretinin, MIC-2 (CD99), S100 protein, PGP 9.5, and neuron-specific enolase. Electron microscopy of the Sertoli cell tumor-like areas showed Charcot-Bottcher filaments, a distinguishing feature of Sertoli cells. Together, these findings supported a diagnosis of mixed sex cord-stromal tumor including granulosa cell tumor of adult and juvenile types and intermediate- to high-grade Sertoli cell tumor, with large areas of markedly atypical sex cord-stromal tumor.

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.

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.

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.

Sertoli-Leydig cell tumor - a rare androgen secreting ovarian tumor in postmenopausal women. Case report and review of literature

Sertoli-Leydig cell tumors (SLCT) constitute only 1-0.5% of all primary ovarian neoplasms. We report a SLCT in a postmenopausal woman aged 69 years. The physical examination revealed severe hirsutism. Basal hormonal evaluation showed high plasma testosterone and estradiol values, with suppressed plasma gonadotropins. Computer tomograph scan revealed a right ovarian tumor mass of 4,3/3 cm, confirming an androgen secreting ovarian tumor. The histopathological and immunocytochemical examination established the diagnosis of well differentiated Sertoli-Leydig cell tumor. The tumor was positive for cytokeratin KL 1 and S-100 protein and, in isolated tumor cells, positive for alpha-fetoprotein. Postsurgical evolution was favorable; controls after 6 months and 3,5 years showed marked reduction of hirsutism, normal plasma testosterone values and gonadotropins in normal postmenopausal range. We discuss the complex aspects of etiology and pathogenesis, the clinical and hormonal settings, the role of immunocytochemical markers in diagnosis, as well as the therapy and the prognostic features of this ovarian tumor.

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.

Immunohistochemistry in gynecological pathology

Although the majority of diagnoses in gynecological pathology are established on examination of routine hematoxylin and eosin stained sections, additional tests are occasionally required. Immunohistochemistry is widely used to provide additional diagnostic information in problematic cases. This review touches on some of the basics of the procedure, presents an example immunohistochemical panel, and discusses some of the most common immunohistochemical markers used in diagnostic gynecological pathology. Differential diagnostic problems and relevant immunohistochemical stains for the vulva, vagina, cervix, uterus, and ovary are also addressed.

Ovarian sex cord-stromal tumors: an immunohistochemical study including a comparison of calretinin and inhibin

Because ovarian sex cord-stromal tumors (SCST) are morphologically heterogeneous neoplasms that are relatively infrequently encountered, their diagnosis can be difficult. Immunohistochemical staining may be useful for establishing the diagnosis in problematic cases. We studied 53 ovarian SCSTs to characterize their immunohistochemical staining pattern: 17 adult granulosa cell tumors (AGCTs), 4 juvenile granulosa cell tumors (JGCTs), 3 sex cord tumors with annular tubules (SCTATs), 9 Sertoli-Leydig cell tumors (SLCTs), 10 fibromas, 5 fibrothecomas (FTs), and 5 thecomas. In 8 of the 53 cases, the tissue studied was from a metastatic site. The immunopanel included calretinin, inhibin, WT1, cytokeratin cocktail, epithelial membrane antigen (EMA), and cytokeratin 5/6 (CK5/6). The fibromas and FTs were also tested with CD10. The extent of staining was assessed in a semiquantitative fashion and ranked on a scale of 0 through 4+. All of the tumors, except for 1 metastatic SLCT, were positive for calretinin. Forty-five of the cases (85%) stained for inhibin; 1 metastatic AGCT, 3 fibromas, and 4 FTs were negative. WT1 was present in 39 tumors (74%), with expression most prominent in the SLCTs. The cytokeratin cocktail stained 23 of the 53 tumors (43%), whereas just 1 tumor was positive for EMA (1+ in a JGCT). All tumors were negative for CK5/6, and the 15 fibromas and FTs were negative for CD10. We conclude that because cytokeratin is frequently expressed by SCSTs, in particular by granulosa cell tumors, SLCTs, and SCTATs, the inclusion of EMA in a panel may help to exclude epithelial neoplasms. In addition, WT1, present in normal granulosa cells, is expressed by a majority of SCSTs. Finally, these results demonstrate that calretinin is at least as sensitive as inhibin for ovarian SCSTs overall and that it is more sensitive than inhibin for fibromas and FTs.

Ovarian steroid cell tumors: an immunohistochemical study including a comparison of calretinin with inhibin

Ovarian steroid cell tumors, not otherwise specified (SCTs, NOS) are uncommon sex cord-stromal tumors that may be difficult to distinguish from other oxyphilic or clear-cell neoplasms. Immunohistochemical staining for inhibin, although generally useful in the diagnosis of SCTs, NOS, is not positive in every case and not all laboratories have this marker available. Recently, it has been reported that calretinin is expressed by sex cord-stromal tumors. We studied six SCTs, NOS for both calretinin and inhibin expression to evaluate the sensitivity of calretinin in comparison to inhibin. We also tested for CD99, Melan-A (A103), and S-100, other markers reported to be positive in these tumors. HMB-45 and MART-1 (Ab3) completed our panel of markers. All six tumors were positive for both calretinin and inhibin. Calretinin positivity was present in 60% to >90% of tumor cells, whereas inhibin reactivity ranged from <5% to >90% of tumor cells. Membranous staining for CD99 was present in one tumor. S-100-positive cells were seen in two tumors, whereas four tumors were immunoreactive for HMB-45. All six tumors were positive for Melan-A (A103), but in general the staining was less diffuse than with calretinin. All of the tumors were essentially negative for MART-1 (Ab3). The consistent diffuse staining of the tumors in this study for calretinin, in comparison to inhibin and Melan-A (A103), suggests that it is a sensitive marker for SCTs, NOS. MART-1 (Ab3) immunostaining may be useful for cases in which melanoma is considered in the differential diagnosis.

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.

Recent advances in immunohistochemistry in gynaecological pathology

Recent years have witnessed significant developments in the use of immunohistochemistry in diagnostic gynaecological pathology. This review details the most significant of these. In ovarian pathology, differential cytokeratin staining (CK7 and 20) assists in distinguishing between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. The development of markers characteristic of ovarian sex cord-stromal tumours (especially alpha-inhibin) facilitates diagnosis of these neoplasms which is often difficult by morphology alone due to the wide differential diagnosis. In the uterus, the distinction between a primary endometrial and endocervical adenocarcinoma may be facilitated by use of a small panel of antibodies, including CEA, ER and vimentin. Newly developed antibodies such as CD10 and h-caldesmon may be of use in the diagnosis of uterine mesenchymal lesions, especially in the distinction between endometrial stromal and smooth muscle lesions. Proliferation markers, such as MIB1, are of value in the cervix in the diagnosis of preinvasive squamous and glandular lesions. Recent studies have shown that cervical adenoma malignum exhibits a gastric phenotype. Advances have also been made in trophoblastic disease with the development of antibodies reactive against trophoblast such as alpha-inhibin, mel-Cam and p57. A newly developed monoclonal antibody HMGIC which is expressed in vulvovaginal aggressive angiomyxoma may prove to be of value in the often difficult distinction of this lesion from its histological mimics.

CD99/MIC-2 surface protein expression in breast carcinomas

AIM

To evaluate the expression of CD99/MIC-2 surface protein in invasive breast carcinomas and demonstrate whether or not there is a relationship with tumour phenotype.

METHODS AND RESULTS

Thirty-five invasive breast carcinomas, including five metaplastic carcinomas, were stained with CD99 primary antibodies using standard protocols based on streptavidin-biotin-peroxidase method. Four out of five metaplastic carcinomas expressed CD99/MIC-2 protein, three of them were matrix-producing carcinomas. From the other 30 cases, only an invasive apocrine carcinoma was positive. There was no statistical correlation between CD99 expression and the parameters analysed (histological typing and grading, proliferative index and nodal status).

CONCLUSIONS

CD99/MIC-2 is expressed in breast carcinomas, especially in the matrix-producing variant of metaplastic carcinomas, which impairs its use as a marker to differentiate metaplastic carcinomas from primary and metastatic sarcomas of the breast. It seems to have no prognostic implications. However, phenotype similarities with other chondromyxoid tumours that also express the protein, like mesenchymal chondrosarcomas, suggest a relationship between MIC-2 reactivity and morphological differentiation.

Clear cell carcinoid tumor of the gallbladder: another distinctive manifestation of von Hippel-Lindau disease

We describe a morphologically distinctive carcinoid tumor of the gallbladder that occurred in a 38-year-old man with von Hippel-Lindau (VHL) disease. The carcinoid tumor was composed predominantly of lipid-containing clear cells arranged in nests and tubules with pagetoid spread into the biliary epithelium and was interpreted as metastatic renal cell carcinoma. The neoplastic cells showed diffuse immunoreactivity for chromogranin, synaptophysin, cytokeratins (cytokeratin 7 and AE1/AE3) and, unexpectedly, for inhibin, but were negative for monoclonal carcinoembryonic antigen, serotonin and a variety of peptide hormones. This clear cell carcinoid tumor of the gallbladder was histologically similar to the recently described clear cell endocrine pancreatic tumor associated with VHL. Four cases of the latter tumor, which were also inhibin positive showed, in addition, focal and variable reactivity for the pancreatic hormones. Two classical carcinoid tumors of the gallbladder, two renal cell carcinomas associated with VHL and 11 of 13 sporadic endocrine pancreatic tumors (not associated with VHL) did not show immunoreactivity for inhibin. Inhibin appears to be an immunohistochemical marker for gallbladder clear cell carcinoid and clear cell endocrine pancreatic tumors associated with VHL and is a useful tool to distinguish these tumors from metastatic renal cell carcinoma. However, the basis for the inhibin positivity in these endocrine tumors is unknown.

Immunohistochemical staining for calretinin is useful in the diagnosis of ovarian sex cord-stromal tumours

AIMS

Ovarian sex cord-stromal tumours are a heterogeneous group of neoplasms which may be confused morphologically with a wide variety of tumours. Calretinin positivity has previously been demonstrated in a small number of ovarian sex cord-stromal tumours. The aim of this study was to investigate calretinin staining in a series of these tumours and their histological mimics in order to determine the value of calretinin staining in a diagnostic setting.

METHODS AND RESULTS

Seventy-two neoplasms, including 37 ovarian sex cord-stromal tumours and 35 miscellaneous neoplasms which may enter into the differential diagnosis, were stained with a commercially available polyclonal antibody against calretinin. All sex cord-stromal tumours exhibited positivity except for a single fibrothecoma. In this group of tumours staining was generally diffuse and strong. Small numbers of the miscellaneous group of neoplasms exhibited positivity but this tended to be focal and weak, although this was not always the case. There was consistent strong positive staining of granulosa cells in follicular cysts and corpora lutea. There was also positive staining of luteinized stromal cells in two cases of ovarian stromal hyperplasia and hyperthecosis.

CONCLUSIONS

Calretinin is a sensitive immunohistochemical marker of ovarian sex cord-stromal tumours and may be useful in a diagnostic setting. However, the value is somewhat limited since occasional neoplasms which enter into the morphological differential diagnosis may be positive. Be that as it may, calretinin positivity may be of value in the diagnosis of an ovarian sex cord-stromal tumour and its differentiation from other neoplasms. In this regard, calretinin should always be used as part of a larger panel.

Value of inhibin staining in gynecological pathology

Recent years have seen the publication of many articles investigating the value of antibodies against inhibin in diagnostic surgical pathology. This review concentrates on the uses of inhibin staining in gynecological pathology. alpha-inhibin is diagnostically the most useful antibody and is a sensitive immunohistochemical marker of most ovarian sex cord-stromal tumors and, as such, is of value in the diagnosis of this heterogeneous group of neoplasms that can be confused morphologically with a wide range of other tumors. Because the antibody is not entirely specific for ovarian sex cord-stromal tumors, it should always be used as part of a larger panel. alpha-inhibin staining may also be of value in confirming late recurrence or metastasis of an ovarian sex cord-stromal tumor, especially a granulosa cell tumor. Sex cord-like elements within uterine tumors resembling ovarian sex cord tumors are also commonly immunoreactive with alpha-inhibin, perhaps indicating true sex cord differentiation. alpha-inhibin staining may also be of value in cytological preparations in confirming a functional cyst and excluding a cyst or cystadenoma of epithelial origin. Syncytiotrophoblastic cells are also immunoreactive, as are most trophoblastic tumors. Thus, positive staining may be of value in confirming an intrauterine gestation or in the diagnosis of a trophoblastic neoplasm. Another gynecological neoplasm that is commonly positive with alpha-inhibin is the so-called female adnexal tumor of probable wolffian origin, and, therefore, the antibody is of no value in the distinction of this neoplasm from a sex cord-stromal tumor, tumors that are often in the differential diagnosis.

Immunohistochemical analysis of gynecologic tumors

Ancillary techniques such as immunohistochemistry (IHC) enable the surgical pathologist to extract additional information from fixed, deparaffinized tissue specimens and to provide data critical to optimal clinical management of the patient. In this review of applications of IHC to the analysis of gynecologic malignancies, the usefulness of immunohistochemical analysis of neoplasms of the cervix, endometrium, and ovary is summarized. In the uterine cervix, dysplasia is associated with qualitative and quantitative alterations in the expression of the Ki-67 antigen expression, as well as an ability to detect human papillomavirus. Endometrial endometrioid adenocarcinomas display a highly characteristic immunophenotype, with coexpression of cytokeratin and vimentin and demonstration of foci of high molecular weight cytokeratin expression; in addition, IHC analysis of estrogen and progesterone receptor and p53 expression can provide important prognostic information about this tumor. Stromal tumors of the endometrium may display a partial smooth muscle immunophenotype, but novel markers such as CD10 provide new tools for the identification of these tumors. The immunophenotypes of the normal ovarian surface epithelium (OSE) and corresponding tumors display significant overlap with, but important distinctions from, mesothelium, and important new markers such as the Wilms tumor gene product can prove useful in the identification of carcinomas of the OSE. Important prognostic markers for carcinomas of the OSE include the HER-2/neu gene product and p53, alterations of which can both be assessed by IHC techniques. Finally, the recent availability of markers of ovarian stroma, including Melan-A and inhibin-alpha, has provided a means for the positive identification of ovarian stromal tumors, which can manifest protean histological appearances.

Signet ring stromal tumor of the ovary occurring in conjunction with brenner tumor

OBJECTIVE

A case is presented of a single ovarian mass that had elements of both signet ring stromal tumor of the ovary and Brenner tumor.

METHODS

The histologic features and the results of histocytochemical, immunohistochemical, and electron microscopic studies are presented.

RESULTS

The signet ring component of the mass demonstrated features consistent with the few other cases previously reported. A positive immunohistochemical stain for the peptide hormone inhibin provides additional evidence for an ovarian stromal origin for this tumor.

CONCLUSION

The tumor produced no hormonally related symptoms and has shown no evidence of recurrence. Signet ring stromal tumor of the ovary is an uncommon benign tumor that may be confused with metastatic signet ring carcinoma. The significance of the signet ring cells is not certain. Their association with Brenner tumor has not been previously described.

Recent advances in immunohistochemistry in the diagnosis of ovarian neoplasms

This leader reviews recent advances in immunohistochemistry that are useful in the diagnosis of ovarian neoplasms. These include the value of different anticytokeratin antibodies in the distinction between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. These antibodies have also helped to clarify the origin of the peritoneal disease in most cases of pseudomyxoma peritonei. The value of antibodies against so called tumour specific antigens, such as CA125 and HAM56, in determining the ovarian origin of an adenocarcinoma is also reviewed. In recent years, several studies have investigated the value of a variety of monoclonal antibodies in the diagnosis of ovarian sex cord stromal tumours and in the distinction between these neoplasms and their histological mimics. These antibodies include those directed against inhibin, CD99, Mullerian inhibiting substance, relaxin like factor, melan A, and calretinin. Of these, anti-alpha inhibin appears to be of most diagnostic value. It is stressed that these antibodies should always be used as part of a larger panel and not in isolation.

Immunoexpression of inhibin alpha subunit, inhibin/activin betaA subunit and CD99 in ovarian tumors

OBJECTIVE

Anti-inhibin alpha and inhibin/activin betaA subunit and anti-CD99 monoclonal antibodies (mAbs) have recently been demonstrated to be able to label ovarian granulosa cells; thus, they may be of value in the diagnosis of granulosa cell tumors. The present study aimed to determine what combination of these mAbs may be useful for the differential diagnosis of sex cord-stromal tumors of ovary.

DESIGN

Immunohistochemical analyses with anti-inhibin alpha and inhibin/activin betaA subunit antibody and anti-CD99 mAb were performed on 42 ovarian tumors, including sex cord-stromal tumors (29), ovarian epithelial cancers (10), and Krukenberg tumors (3).

RESULTS

All sex cord-stromal tumors were positive for inhibin alpha subunit, and 17 cases (58.6%) of sex cord-stromal tumors were immunoreactive for inhibin/activin betaA subunit. Epithelial tumors and Krukenberg tumors were all negative for inhibin/activin betaA subunit except mucinous carcinoma, which showed strong cytoplasmic immunoreactivity. All sex cord-stromal tumors except one granulosa cell tumor showed membranous staining for CD99. A case of serous carcinoma and a case of mucinous carcinoma were positive for CD99, and the remaining epithelial tumors and Krukenberg tumor were all negative for CD99.

CONCLUSIONS

The results of immunohistochemical analysis, together with literature review, suggest that inhibin alpha subunit may be a useful diagnostic marker for sex cord-stromal tumor of the ovary. In addition, anti-CD99 antibody may be useful for the differential diagnosis between ovarian tumors. Inhibin/activin betaA subunit has a limited usefulness in the differential diagnosis of ovarian tumor because of its wider immunoreactivity for both sex cord-stromal tumors and mucinous carcinomas. The differential diagnosis of sex cord-stromal tumors of the ovary would be better made with a combined use of both anti-inhibin alpha subunit and anti-CD99 mAbs.

Hormonally Functional Ovarian Neoplasms

Hormonally functional ovarian neoplasms are those tumors that secrete one or more hormones that are clinically manifested in the patient. The hormone production may have implications for the diagnosis, management or treatment of the patient. Hormonally functional ovarian neoplasms include tumors that belong to various histologic categories and produce a variety of hormonal effects. Functional ovarian tumors most commonly produce steroid hormones, and such tumors frequently belong in the sex cord-stromal and steroid cell categories. In addition, a wide variety of peptide hormones may be produced by ovarian tumors. Although in most instances the neoplastic cells themselves produce the hormones, a wide variety of tumors may induce their stroma to produce steroid hormones. The stroma of ovarian tumors is derived from the ovarian stroma and may, on occasion, resemble specialized ovarian stroma and its derivatives. Cells resembling luteinized stromal cells or luteinized theca cells may be present and appear to be responsible for the resultant hormone secretion.