Large cell calcifying Sertoli cell tumour: molecular and immunohistochemical assessment of a series comprising non-metastasising and metastasising neoplasms.

Large cell calcifying Sertoli cell tumour (LCCSCT) is a type of testicular sex cord-stromal tumour that may occur sporadically or in the context of Carney complex and other genetic syndromes. A subset is clinically malignant, and the molecular mechanisms that drive such aggressive behaviour remain unknown. METHODS AND RESULTS: We analysed 21 samples from 20 patients with LCCSCT (12 non-metastasising and eight metastasising) using PRKAR1A immunohistochemistry (IHC) and next-generation sequencing. All tumours except two (cases 17 and 20, both metastasising) demonstrated loss of PRKAR1A expression. Among 11 cases with interpretable sequencing results, all harboured pathogenic single nucleotide variants of PRKAR1A. Evidence of loss of heterozygosity (LOH) of PRKAR1A was present in all tumours with interpretable zygosity data, but the mechanisms of LOH were different for non-metastasising and metastasising tumours. Non-metastasising tumours demonstrated only copy-neutral LOH, while metastasising tumours demonstrated a spectrum of mechanisms of LOH, including copy-loss LOH, two concurrent mutations or copy-neutral LOH. Relevant molecular findings in non-metastasising LCCSCT were limited to PRKAR1A variants. In contrast, all metastasising LCCSCTs with interpretable data harboured additional pathogenic variants, including (but not restricted to) BRCA2 mutations with evidence of LOH and bi-allelic CDKN2A/B deletions. Three patients harboured PRKAR1A variants of inferred germline origin, including one with Carney complex and two without known syndromic features. CONCLUSIONS: This study further confirms that PRKAR1A IHC is a useful diagnostic tool for both non-metastasising and metastasising tumours and suggests that molecular analyses can be helpful to identify non-metastasising tumours with malignant potential in selected patients. Importantly, these results highlight that germline assessment could be beneficial for all patients presenting with LCCSCT.

Sex cord stromal tumors and tumors of the paratestis: new and old entities in a landscape of rare tumors.

PURPOSE OF REVIEW: The 5th edition of WHO classification incorporates the most relevant new data available in the literature regarding tumors of the male genitourinary tract. In this review, the authors summarize and critically discuss the most relevant new information regarding tumors occurring in the stromal testis and in the paratestis that will be reported in the new edition of WHO classification of tumors of the male genitourinary tract. RECENT FINDINGS: Signet-ring stromal tumors (SRST) and myoid gonadal stromal tumors (MGST) are two new entities brought in the 5th WHO classification of testicular tumors. All cases of SRST and MGST reported so far have behaved in a benign fashion after resection and whenever possible a conservative surgery is recommended. A future perspective is to aim at creating large multiinstitutional case series to link different morphologic patterns and molecular bases to the biologic behavior of these neoplasms. Another innovation in WHO consists in the inclusion in the group of Sertoli cell tumors of the sertoliform cystadenoma. The sertoliform cystadenoma is localized in the rete testis and it is of unknown origin. It was included in the group of gonadal stromal tumors because of a high morphological and immunohistochemical similarity to the Sertoli cell tumor. SUMMARY: Although further studies with long-term follow-up are needed to estimate the main oncologic outcomes in patients with rare gonadal stromal tumors, we highlight the importance of an accurate characterization by molecular and immunohistochemical assays of these entities.

Large cell calcifying Sertoli cell tumour: a contemporary multi-institutional case series highlighting the diagnostic utility of PRKAR1A immunohistochemistry.

AIMS: Large cell calcifying Sertoli cell tumour (LCCSCT) is a rare testicular sex cord-stromal tumour that primarily affects young patients and is associated with Carney complex. We sought to characterise the clinicopathological features of a series of LCCSCT and evaluate the diagnostic utility of PRKAR1A immunohistochemistry (IHC). METHODS AND RESULTS: The LCCSCT cohort (n = 15) had a median age of 16 years (range = 2-30 years). Four patients were known to have Carney complex. PRKAR1A IHC was performed in each case. For comparison, PRKAR1A IHC was also assessed in other sex cord-stromal tumours, including Sertoli cell tumour, not otherwise specified (SCT, NOS; n = 10), intratubular large cell hyalinising Sertoli cell tumour (n = 1) and Leydig cell tumour (n = 23). Loss of cytoplasmic PRKAR1A expression was observed in all but one LCCSCT (14 of 15; 93%). PRKAR1A expression was retained in all SCTs, NOS (10 of 10; 100%), the majority of Leydig cell tumours (22 of 23; 96%) and an intratubular large cell hyalinising Sertoli cell tumour (1 of 1; 100%). One Leydig cell tumour showed equivocal staining (multifocal weak expression). CONCLUSIONS: Overall, PRKAR1A loss is both sensitive (93%) and highly specific (97%) for the diagnosis of LCCSCT. PRKAR1A loss may aid its diagnosis, particularly in sporadic cases and those that are the first presentation of Carney complex.

A Morphologic and Immunohistochemical Comparison of Nuclear ß-Catenin Expressing Testicular Sertoli Cell Tumors and Pancreatic Solid Pseudopapillary Neoplasms Supporting Their Continued Separate Classification.

Some recent reports suggested that many Sertoli cell tumors, not otherwise specified (SCTs-NOS) of the testis were analogs of the solid pseudopapillary neoplasm (SPN) of the pancreas. One of the most relied on pieces of information for this assertion was the shared occurrence in both neoplasms of exon 3 mutations of the CTNNB1 gene, which was reflected by nuclear ß-catenin expression. We, therefore, compared the morphologic and immunohistochemical features of 18 SCTs-NOS with strong, diffuse nuclear ß-catenin expression with 16 SPNs that also showed such positivity. Although there were clear similarities in the light microscopic features of these neoplasms, there were also significant differences that included, in SCT-NOS and SPN, respectively: hollow tubules (53% vs. 0%), sheet-like growth (44% vs. 94%), circumscription (79% vs. 25%), corded or trabecular patterns (81% vs. 31%), formation of papillae or pseudopapillae (24% vs. 69%), growth in nests or clusters (94% vs. 50%), perivascular pseudorosettes (13% vs. 56%), and rhabdoid cytology (6% vs. 50%). Commonly shared morphologic features included signet-ring cells, pale or foamy cytoplasm, myxoid stroma, cyst formation, perivascular hyalinization, and globular or band-like basement membrane deposits. On immunohistochemical study, sex cord markers were frequently positive in SCTs-NOS (steroidogenic factor-1-94%; FOXL2-87%; SOX9-69%; calretinin-60%; Wilms tumor-1-38%; inhibin-29%) whereas all of these markers were negative in the SPNs. We conclude that even though SCT-NOS and SPN share some morphologic features and nuclear immunoreactivity for ß-catenin, there remain differences, both morphologically and immunohistochemically, between these neoplasms to the degree that SCT-NOS should not be equated with pancreatic SPN.

The Morphologic Spectrum of Sertoliform Cystadenoma of the Rete Testis: A Series of 15 Cases.

Sertoliform cystadenoma of the rete testis (SCRT) is rare with only 9 cases reported to date in the literature, none with follow-up. Four large genitourinary pathology consult services were searched. We identified 15 cases of SCRT. Men were 21 to 84 years old (mean, 46 y) and had testicular discomfort or mass. Other findings were seminoma (n=1), spermatocele (n=2), hydrocele (n=1), varicocele (n=1), and scrotal hematoma (n=1). Eight had preoperative serum tumor markers, which were normal. Tumors ranged from 0.3 to 4 cm (mean, 1.5 cm). All of them were well circumscribed with solid and cystic features and occupied on average, 73% of the rete (20% to 100%). The tumors were mostly confined within dilated channels of the rete testis and showed classic features consisting of: (1) tubules with well-formed lumina in 87% of cases; (2) well-formed tubules with no lumina in 87% of cases; and (3) cords/nests in hyalinized or myxoid stroma in 73% of cases. Other patterns included: (1) solid/sheet growth in 26% of cases; (2) individual cells in 13% of cases; (3) festoons in 13% of cases; (4) branching tubules in 7% of cases; and (5) papillary in 7% of cases. Cells were cuboidal with round to oval nuclei with small nucleoli, except at the periphery where projections into rete tubules had a more columnar appearance. In the festooning pattern, nuclei were pseudostratified and columnar with prominent nucleoli and nuclear grooves. In 4 cases, tumor extended into adjacent seminiferous tubules surrounded by dense peritubular fibrosis, with in some cases small cysts lined by flattened epithelium containing pale lightly granular material. All cases lacked necrosis and significant atypia. Mitoses ranged from 0 to 2 per 10 high-power field. Follow-up ranged from 4 to 170 months with mean of 97 months. For the 13 cases with information, all patients were alive, except for 3 who died of either unrelated causes (9.2 and 10 y) or of unknown cause (4.8 y at age 89 y). We performed immunohistochemistry for steroidogenic factor 1 and inhibin in 4 of our cases, where 3 (75%) were positive for both markers. We also describe 2 additional cases which morphologically resembled SCRT but had more atypical features. This study highlights that SCRT has variable morphology. We also verify the benign nature of the lesion and its lack of association with any syndromes.

Immunophenotypic comparison of testicular sclerosing Sertoli cell tumors and Sertoli cell tumors not otherwise specified.

Testicular Sertoli cell tumors (SCTs) are rare, and most fall into the category of SCT-not otherwise specified (SCT-NOS). Only a few additional types of SCT are recognized. Sclerosing SCT (S-SCT), originally described in 1991, comprises a small fraction of SCTs and was considered a specific entity until the 2016 revision of the World Health Organization classification of non-germ cell tumors, where it was classified as a morphologic variant of SCT-NOS. In a recent study, differences in expression of PAX2/PAX8, inhibin, androgen receptor, and S100 protein between SCT-NOS and S-SCT were noted in a small number of cases. In this interinstitutional study, we compared the expression of these markers and ß-catenin in 11 cases each of SCT-NOS and S-SCT to determine if differences exist that could justify keeping a separate classification of these neoplasms. PAX2/PAX8 cocktail was the only marker that was significantly overexpressed in S-SCT. Expression of androgen receptors was strong in S-SCT and variable in SCT-NOS but did not reach statistical significance. Expression of ß-catenin was common in both, whereas inhibin was infrequent. The available material was insufficient for a conclusive evaluation of S100 protein expression. Overall, our results support the inclusion of S-SCT as a morphologic variant of SCT-NOS. Expression of PAX2/PAX8 in S-SCT may reflect an overactive epithelial-to-mesenchymal transition as has been shown in experimental models of acute and chronic seminiferous tubular injury and might be related to the process generating the stroma in these tumors.

Nuclear Localization of ß-Catenin in Sertoli Cell Tumors and Other Sex Cord-Stromal Tumors of the Testis: An Immunohistochemical Study of 87 Cases.

The diagnosis and subclassification of Sertoli cell tumors (SCT) of the testis are often challenging to general surgical pathologists because of the rarity of the tumors. Immunohistochemical study to date has limited diagnostic value. Nuclear localization of ß-catenin, which correlated closely with CTNNB1 gene mutation, was recently reported in SCTs. We investigated the utility of ß-catenin nuclear localization in diagnosing SCTs and differentiating them from other testicular sex cord-stromal tumors. Immunohistochemical staining for ß-catenin was evaluated in 87 cases of testicular sex cord-stromal tumor: 33 SCTs, not otherwise specified (SCT-NOS) (15 with benign and 18 with malignant features), 10 sclerosing SCTs (SSCT), 5 large cell calcifying SCTs (LCCSCT), 6 Sertoli-stromal cell tumors, 10 Leydig cell tumors, 7 juvenile granulosa cell tumors, 4 adult granulosa cell tumors, and 12 sex cord-stromal tumors, unclassified. Twenty-one of 33 (64%) SCT-NOS, 6 of 10 (60%) SSCTs, and 4 of 6 (67%) Sertoli-stromal cell tumors showed strong, diffuse ß-catenin nuclear staining. Nuclear ß-catenin positivity was more frequent in SCTs-NOS with benign features than in those with malignant features (93% and 39%, respectively, P=0.13) and, in the Sertoli-stromal cell tumors, occurred only in the Sertoli component. All 5 LCCSCTs and all other types of sex cord-stromal tumor were negative for ß-catenin nuclear staining. In conclusion, SCT-NOS and SSCT frequently show ß-catenin nuclear localization. Positive nuclear staining of ß-catenin is specific for SCT-NOS, SSCT, and Sertoli-stromal cell tumor among testicular sex cord-stromal tumors but has limited sensitivity (63%) in this group. The similar reactivity of SCT-NOS and SSCT provides additional support that these 2 variants are not distinct entities.

Immunohistochemical Characterization of Spontaneous Sertoli Cell Clusters in the Seminiferous Tubules of C57BL/6J Mice.

Cell clusters were observed in the seminiferous tubules of C57BL/6J mice as a spontaneous lesion in a 2-week toxicity study, and they were demonstrated to be basically composed of Sertoli cells by immunohistochemistry for claudin-11 and GATA-4 (GATA-binding protein 4), which are both Sertoli cell markers. The clusters were composed of about 5 to 50 cells, which had eosinophilic and occasionally vacuolated cytoplasm with an unclear cell boundary. The cell clusters involved some sperm. No mitotic figures were observed and no immunoreactivity for proliferating cell nuclear antigen (PCNA) was detected in the clusters. In most cases, the cell clusters were observed in seminiferous tubules that also showed degenerative changes. In rare instances, cell aggregates immunohistochemically positive for claudin-11 were observed in the lumen of the epididymis, suggesting that some of the Sertoli cell clusters were sloughed off from the seminiferous epithelium into the epididymal ducts. To our knowledge, this is the first report of Sertoli cell clusters in any animal species except for transgenic or surgically altered animals.

Bilateral Sertoli cell adenoma in gonads, associated with serous cystadenoma.

Complete androgen insensitivity syndrome is an extremely infrequent disease. The patients exhibit female phenotype because of insensitivity to the androgen receptor and may develop tumors, especially in their undescended gonads. We report a case of bilateral Sertoli cell adenoma in gonads with unilateral serous cystadenoma, in an elderly phenotypic woman with primary amenorrhea. We also provide radiological and pathological studies.

Frequent mutation and nuclear localization of ß-catenin in sertoli cell tumors of the testis.

The Sertoli cell tumor (SCT) of the testis is a sex cord stromal tumor, usually sporadic, rarely associated with genetic syndromes. Much remains unclear about the molecular genetic changes involved in SCT and its histogenesis. Recently, nuclear ß-catenin immunostaining has been reported in a case of bilateral SCT, but the molecular basis of the aberrant nuclear ß-catenin expression remains uncertain. In the present study, ß-catenin immunohistochemical assay and mutational analysis of exon 3 of the CTNNB1 gene by direct sequencing were performed in 14 SCTs, 2 of which had an unfavorable clinical course. Immunohistochemical study showed that ß-catenin was located in the cytoplasm of tumor cells in 4 cases (28.6%) and in both the nuclei and the cytoplasm in the remaining 10 cases (71.4%). ß-Catenin mutations were detected in 10 of the 14 patients (71.4%) under evaluation. Ten of 10 mutation-carrying cases showed strong nuclear and diffuse cytoplasmic ß-catenin immunoreactivity. Seven of the 8 CTNNB1-mutated tumors tested for cyclin D1 displayed diffuse immunoreactivity in the nuclei of tumor cells. We conclude that CTNNB1 exon 3 mutations are likely to be involved in the pathogenesis of male SCT with nuclear accumulation of ß-catenin and affect the expression of cyclin D1.

[Large cell calcifying Sertoli cell tumour: A case report]. / La tumeur à cellules de Sertoli à grandes cellules calcifiantes : à propos d'un cas.

A 19-year-old male Caucasian, without prior medical history, noticed a painless right testicular mass. Physical examination revealed neither gynecomastia nor abnormal skin pigmentation. Serum alpha-fetoprotein, ß-HCG and testosterone levels were normal. Sonography depicted an intratesticular diffusely hyperechoic lesion with acoustic shadowing. The patient underwent right orchiectomy. Histology revealed a benign large cell calcifying Sertoli cell tumour. This tumour is rare and may be associated with genetic abnormalities.

Sertoliform cystadenoma: a rare benign tumour of the rete testis.

Sertoliform cystadenoma of the rete testis represents an uncommon benign tumour. They appear in patients from 26 to 62 years of age. We describe a case of a 66-year-old man with a tumour in the area of the epididymal head. The tumour markers were not increased. Under the assumption of a malignant testicular tumour an inguinal orchiectomy was performed. The cut surface of this tumour was of grey/white color and showed small cysts. The tumour consisted of two compartments. The epithelial like tumour cells showed a sertoliform growth pattern and cystic dilatations. In between the tumour cells repeatedly actin expressing sclerotic areas could be recognized as the second tumour component. Proliferative activity was not increased. Immunohistochemically the tumour cells were positiv for inhibin, S-100, and CD 99. Alpha feto protein (AFP), human chorionic gonadotropin (ß-HCG) and placental alkaline phosphatase (PLAP) as well as synaptophysin, epithelial membrane antigene (EMA), and BCL-2 were not expressed. As far as we know this is the sixth reported case of this tumour. Because of the benign nature of this tumour the correct diagnosis is important for the intra- and postoperative management. Here we present a case of this rare tumour and discuss potential differential diagnosis. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1956026143857335.

Sclerosing Sertoli cell tumor without expression of typical sex cord stromal tumor markers: case report and literature review.

Sertoli cell tumor is a potential histologic mimic of other tumors, such as seminoma due to similar histology and overlapping clinical presentation. Sclerosing Sertoli cell tumor is a rare sex cord stromal tumor variant, with 16 cases reported in the English literature. We present an unusual case of sclerosing Sertoli cell tumor in a 33-year-old Caucasian male, which was negative or weakly reactive using immunohistochemical markers typically positive in Sertoli cell tumors. The tumor was positive for cytokeratin AE1/AE3, CAM 5.2, vimentin, CD56, CK8, synaptophysin and S100, and negative for inhibin, calretinin, WT1, CD99, CD117, CK5/6, CK7, chromogranin A, placental alkaline phosphatase, neuron specific enolase, D2-40, smooth muscle actin, Melan-A, epithelial membrane antigen and carbonic anhydrase IX. This is the second reported case of a Sertoli cell tumor with reactivity limited to neuroendocrine markers and the first such case of the sclerosing variant. A literature review of sclerosing Sertoli cell tumor, including English and non-English literature, is described. Our case highlights that expected immunohistochemical markers may be negative, and awareness of antigenically unreactive tumors is needed to avoid confusion between Sertoli cell tumor and other entities.

Diagnostic utility of WT1 immunostaining in ovarian sertoli cell tumor.

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

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.

Expression of galectin-3 in gonads and gonadal sex cord stromal and germ cell tumors.

Galectin-3, a beta-galactoside-binding lectin, has been implicated in many human malignancies, but has seldom been studied in human gonads and gonadal tumors. The aim of our study was to investigate galectin-3 mRNA and protein expression in normal ovaries and testes as well as in a variety of 51 gonadal sex cord stromal and germ cell tumors, and two testicular seminomatous and non-seminomatous cell lines, using either real-time PCR or immunohistochemistry. In human testes, galectin-3 is specifically expressed in mature Sertoli cells and Leydig cells, and is absent from fetal and pre-pubertal testes, suggesting a hormone-dependence of this gene. In human ovaries, galectin-3 is absent from granulosa cells, as well as from granulosa cell and Sertoli-Leydig cell tumors, and is not a useful marker in distinguishing granulosa cell from Sertoli-Leydig cell tumors. In testicular tumorigenesis, galectin-3 has a dual function according to the histological type of tumors and their hormone dependency. In malignant testicular Sertoli cell tumors, the expression of galectin-3 is down-regulated while, in benign Leydig cell tumors, this expression is maintained, indicating the possible implication of this gene in the development of more aggressive testicular sex cord stromal tumors. In contrast to sex cord stromal tumors, galectin-3 expression is up-regulated in testicular germ cell tumors. By real-time PCR, we demonstrated a significant elevation of the galectin-3 mRNA level in non-seminomatous testicular germ cell tumors and cell line as compared to normal testes and seminomas (p=0.0432 and p=0.0247, respectively), indicating the possible role of this gene in the non-seminomatous differentiation of germ cell tumors.

OCT4 staining in testicular tumors: a sensitive and specific marker for seminoma and embryonal carcinoma.

OCT4 (POU5F1) is a transcription factor expressed in embryonic stem and germ cells and is involved in the regulation and maintenance of pluripotency. It has been detected in primary testicular germ cell tumors with pluripotent potential, seminoma, and embryonal carcinoma. We undertook immunohistochemical staining of OCT4 in a wide variety of primary testicular neoplasms (germ cell tumors and other tumors) to assess the specificity and usefulness of this marker as a diagnostic tool. We examined histologic sections from 91 primary testicular neoplasms, including 64 cases of mixed germ cell tumors containing embryonal carcinoma (54), seminoma (51), yolk sac tumor (38), mature teratoma (31), immature teratoma (20), and choriocarcinoma (15). In addition, we examined sections from spermatocytic seminomas (5), Leydig cell tumors (8), Sertoli cell tumors (6), unclassified sex-cord stromal tumors (4), adenomatoid tumors (2), testicular tumor of adrenogenital syndrome (1), and granulosa cell tumor (1). Each tumor was examined with hematoxylin and eosin staining and with antibodies to OCT4. In all cases of mixed germ cell tumor with components of embryonal carcinoma (54) and seminoma (51), there was greater than 90% nuclear staining of the embryonal carcinoma and seminoma tumor cells with little to no background staining. In all but 1 of these cases (embryonal carcinoma), there was strong (3+) staining intensity. The other germ cell tumor components (yolk sac tumor, mature teratoma, immature teratoma, and choriocarcinoma) showed no staining. Syncytiotrophoblast cells, which were present in 15 of the cases, were also completely negative, as were all 5 of the spermatocytic seminomas. The 22 cases of non-germ cell tumors were all immunohistochemically negative for OCT4. Fifteen of the 54 germ cell tumors containing embryonal carcinoma were also examined with antibodies to CD30. These embryonal carcinoma components were all positive for CD30 with staining of greater than 90% of the tumor cells but with variable staining intensity. We conclude that immunostaining with antibodies to OCT4 is a useful diagnostic tool in the identification of primary testicular embryonal carcinomas and "usual," but not spermatocytic, seminomas. OCT4 immunostaining has comparable sensitivity but greater consistency compared with CD30 in the diagnosis of embryonal carcinoma.