Contemporary Updates on Sex Cord-stromal Tumors of the Testis.

Testicular sex cord-stromal tumors (TSCSTs) are relatively rare, representing ~5% of testicular neoplasms overall. Historically, TSCSTs have been classified into 3 major entities: Leydig cell tumor, Sertoli cell tumor, and granulosa cell tumor. In recent years, immunophenotypic and molecular analyses have led to a more detailed understanding of the biological and genomic features of these neoplasms, resulting in the description of new entities, some of which have been included in the latest WHO classification. This review summarizes novel histopathologic, clinical, and molecular findings that may lead to a reappraisal of established concepts and help improve the diagnosis and clinical management of TSCSTs in the coming years.

Molecular characterization of large cell calcifying sertoli cell tumors: A multi-institutional study of 6 benign and 2 malignant tumors.

Large cell calcifying Sertoli cell tumors (LCCSCTs) are rare testicular tumors, representing <1 % of all testicular neoplasms. Almost 40 % of patients with LCCSCTs will present in the context of the inherited tumor predisposition syndrome, the Carney complex. While most LCCSCTs are benign, 10-20 % have malignant behavior. The aim of our study was to analyze LCCSCTs for novel molecular alterations in addition to PRKAR1A mutations and to identify potential drivers for malignant progression. Eight LCCSCTs diagnosed at two institutions were included. Two patients had the Carney complex confirmed on subsequent genetic testing, and two tumors had several adverse pathological findings. One patient presented with metastatic disease at the time of initial diagnosis. Targeted next-generation sequencing detected PRKAR1A alterations in all cases, with heterozygous PRKAR1A mutations in 5 tumors, germline Carney-complex-associated PRKAR1A mutation in 2 patients, and PRKAR1A fusion in 1 tumor. Additionally, sequencing the metastatic case identified CDKN1B and TERT promoter gene mutations. All tumors showed a low tumoral mutational burden and unremarkable copy number alterations except for frequent LOH of 17q24 encompassing the PRKAR1A locus. RNA expression analysis showed increased expression of several markers including novel PRUNE2, and usual markers like inhibin and calretinin. Our study showed that while LCCSCTs have been reported in the setting of cancer predisposition syndromes, the majority of these tumors occur sporadically. PRKAR1A alterations were present in all cases and appear to be the major driver in LCCSCTs. It remains to be determined whether malignant progression may be caused by additional driver mutations.

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.

Molecular Correlates of Aggressive Behavior and Biological Progression in Testicular Sertoli Cell Tumors.

Sertoli cell tumor (SCT) is the second most common type of sex cord-stromal tumor in men, and ∼10% exhibit malignant behavior. Although CTNNB1 variants have been described in SCTs, only a limited number of metastatic cases have been analyzed, and the molecular alterations associated with aggressive behavior remain largely unexplored. This study evaluated a series of nonmetastasizing and metastasizing SCTs using next-generation DNA sequencing to further characterize their genomic landscape. Twenty-two tumors from 21 patients were analyzed. Cases were divided into metastasizing SCTs and nonmetastasizing SCTs. Nonmetastasizing tumors were considered to have aggressive histopathologic features if they exhibited ≥1 of the following: size >2.4 cm, necrosis, lymphovascular invasion, ≥3 mitoses per 10 high-power fields, severe nuclear atypia, or invasive growth. Six patients had metastasizing SCTs, and the remaining 15 patients had nonmetastasizing SCTs; 5 nonmetastasizing tumors had ≥1 aggressive histopathologic feature(s). Gain-of-function CTNNB1 or inactivating APC variants were highly recurrent in nonmetastasizing SCTs (combined frequency >90%), with arm-level/chromosome-level copy number variants, loss of 1p, and CTNNB1 loss of heterozygosity occurring exclusively in CTNNB1-mutant tumors with aggressive histopathologic features or size >1.5 cm. Nonmetastasizing SCTs were almost invariably driven by WNT pathway activation. In contrast, only 50% of metastasizing SCTs harbored gain-of-function CTNNB1 variants. The remaining 50% of metastasizing SCTs were CTNNB1-wild-type and harbored alterations in the TP53, MDM2, CDKN2A/CDKN2B, and TERT pathways. These findings suggest that ∼50% of aggressive SCTs represent progression of CTNNB1-mutant benign SCTs, whereas the remaining ones are CTNNB1-wild-type neoplasms that exhibit alterations in genes of the TP53, cell cycle regulation, and telomere maintenance pathways.

A 14-Year-Old Saudi Boy with Gynecomastia, Cushing Syndrome, Large-Cell Calcifying Sertoli Cell Tumor of the Testis, and Carney Complex.

BACKGROUND Carney complex (CNC) is a rare multiple neoplasia syndrome with autosomal dominant inheritance. CNC is frequently misdiagnosed owing to its diverse clinical characteristics. We reported the case of a 14-year-old Saudi boy with a history of gynecomastia, Cushing syndrome, large-cell calcifying Sertoli cell tumor of the testis, and CNC. CASE REPORT The patient was referred to the pediatric endocrine clinic for evaluation of bilateral slow progressing gynecomastia for 1-year duration. His clinical examination revealed lentigenes, bilateral diffuse breast enlargement (consistent with Tanner stage III), and asymmetrical testicular enlargement, more on the left side. Other systemic examinations were unremarkable. The initial blood workup showed elevated estradiol level with unsuppressed cortisol after an overnight 1-mg dexamethasone suppression test. Breast ultrasound (US) confirmed true gynecomastia. Testicular US revealed microcalcification and the testicular biopsy confirmed diagnoses of large-cell calcifying Sertoli cell tumor (LCCSCT). A 2-step dexamethasone suppression test showed a paradoxical rise in serum and urine cortisol levels, which are characteristic for PPNAD. LCCSCT and PPNAD are 2 major criteria fulfilling a diagnosis of CNC. The gene test showed heterozygous mutation in the PRKAR1A gene, which is diagnostic for CNC. The patient underwent bilateral mastoplasty and was planned for radical left orchiectomy. CONCLUSIONS Gynecomastia and LCCSCT can be presenting features of CNC, which mandates careful, thorough clinical examination and tailored investigation to reach a diagnosis.

Testicular Sertoli cell tumour and potentially testicular Leydig cell tumour are features of DICER1 syndrome.

DICER1 syndrome is a rare paediatric autosomal dominant inherited disorder predisposing to various benign and malignant tumours. It is caused by a germline pathogenic variant in DICER1, and the second hit for tumour development is usually a missense hotspot pathogenic variant in the DICER1 ribonuclease IIIb domain. While DICER1 predisposing variants account for about 60% of ovarian Sertoli-Leydig cell tumours, no DICER1-related testicular stromal tumours have been described. Here we report the first two cases of testicular stromal tumours in children carrying a DICER1 germline pathogenic variant: a case of Sertoli cell tumour and a case of Leydig cell tumour diagnosed at 2 and 12 years of age, respectively. A somatic DICER1 hotspot pathogenic variant was detected in the Sertoli cell tumour. This report extends the spectrum of DICER1-related tumours to include testicular Sertoli cell tumour and potentially testicular Leydig cell tumour. Diagnosis of a testicular Sertoli cell tumour should prompt DICER1 genetic testing so that patients with a DICER1 germline pathogenic variant can benefit from established surveillance guidelines. DICER1 genetic evaluation may be considered for testicular Leydig cell tumour. Our findings suggest that miRNA dysregulation underlies the aetiology of some testicular stromal tumours.

An Unusual Presentation of Carney Complex

Carney complex (CNC) is a multiple neoplasia syndrome, characterized by pigmented lesions of the skin and mucosa, cardiac, cutaneous and other myxomas and multiple endocrine and non-endocrine tumors. Most of the cases have an inactivating mutation in the PRKAR1A gene. Osteochondromyxoma (OMX) is an extremely rare myxomatous tumor of bone, affecting 1% of CNC patients. Large cell calcifying Sertoli cell tumor (LCCSCT) is a testicular tumor affecting more than 75% of males with CNC. Here, we report an atypical case of CNC without typical pigmented skin lesions, presenting with a bone based tumor as the first manifestation. Initial presentation was for a recurrent, locally invasive intranasal tumor without definite diagnosis. Further clinical developments during follow up, central precocious puberty and testicular tumor with calcification, led to the diagnosis of LCCSCT, a CNC-related tumor. Histopathologic examination of the intranasal tumor was re-evaluated with this knowledge and OMX was diagnosed. Coexistence of OMX and LCCSCT suggested CNC. Genetic analysis revealed a heterozygous non-sense p.Trp 224* (c.672G>A) in the PRKAR1A gene. In our case, the diagnosis of OMX was delayed, because it is extremely rare and little is known about this tumor. Thus the aim of this report was to alert other clinicians to consider CNC if OMX is diagnosed.

Phenotype evolution and health issues of adults with Beckwith-Wiedemann syndrome.

BACKGROUND: Beckwith-Wiedemann syndrome (BWS) phenotype usually mitigates with age and data on adulthood are limited. Our study aims at reporting phenotype evolution and health issues in adulthood. METHODS: 34 patients (16 males), aged 18-58 years (mean 28.5) with BWS were enrolled. RESULTS: 26 patients were molecularly confirmed, 5 tested negative, and 3 were not tested. Final tall stature was present in 44%. Four patients developed Wilms' Tumor (2, 3, 5, and 10 years, respectively); one hepatoblastoma (22 years); one acute lymphoblastic leukemia (21 years); one adrenal adenoma and testicular Sertoli cell tumor (22 and 24 years, respectively); and three benign tumors (hepatic haemangioma, uterine myoma, and mammary fibroepithelioma). Surgery for BWS-related features was required in 85%. Despite surgical correction several patients presented morbidity and sequelae of BWS pediatric issues: pronunciation/swallow difficulties (n = 9) due to macroglossia, painful scoliosis (n = 4) consistent with lateralized overgrowth, recurrent urolithiasis (n = 4), azoospermia (n = 4) likely consequent to cryptorchidism, severe intellectual disability (n = 2) likely related to neonatal asphyxia and diabetes mellitus (n = 1) due to subtotal pancreatectomy for intractable hyperinsulinism. Four patients (two males) had healthy children (three physiologically conceived and one through assisted reproductive technology). CONCLUSIONS: Adult health conditions in BWS are mostly consequent to pediatric issues, underlying the preventive role of follow-up strategies in childhood. Malignancy rate observed in early adulthood in this small cohort matches that observed in the first decade of life, cumulatively raising tumor rate in BWS to 20% during the observation period. Further studies are warranted in this direction.

Case Report of Misleading Features of a Rare Sertoli Cell Testicular Tumor.

Testicular Sertoli cell tumors are extremely rare. Generally, they are benign neoplasms, which belong to a group called sex cord-stromal tumors. In this article, we present a case report of a Sertoli cell tumor, which was accidentally discovered during a urological consultation of a 42-year-old male. An ultrasound showed a 2.1 x 2.2 cm hypoechogenic, hypervascular tumor in the middle third of the left testicle. Serum tumor markers (α-fetoprotein, alkaline phosphatase, ß-human chorionic gonadotropin, and lactic dehydrogenase) were all within the normal range. Rapid microscopic evaluation of fresh frozen sections during the operation was inconclusive, which led to a decision not to perform a radical orchiectomy immediately. On formalin-fixed paraffin-embedded (FFPE) sections, the tumor histology showed atypical patterns, and immunohistochemical analysis was performed in order to determine the type of neoplasm and differentiate it from other types of testicular tumors, so as to assign the further course of treatment. Radical inguinal orchiectomy was performed. The final pathology report showed a tumor with no predictive signs of aggressive behavior, which most closely resembled a Sertoli cell tumor.

Possible hints and pitfalls in diagnosing Peutz-Jeghers syndrome.

Background Peutz-Jeghers syndrome (PJS) is characterized by gastrointestinal polyposis, mucocutaneous pigmentation and cancer predisposition. Patients with PJS can develop large calcifying Sertoli cell tumors (LCSTs). Case presentation A patient presented at 3 years of age with delayed development, hypermobility and later also with tall stature and advanced bone age. Extensive endocrine evaluation, mutation analysis of genes associated with connective tissue disorders and a single nucleotide polymorphism (SNP) array showed no abnormalities. At 8 years of age, gynecomastia developed as well as pigmentations on the lips, both of which are associated with PJS. Mutation analysis showed a heterozygous deletion of the whole STK11 gene confirming PJS. Testicular ultrasound confirmed the presence of LCSTs. Interestingly, the previously performed SNP array did not report deletion of the STK11 gene. Conclusions We advise excluding LCSTs in children with tall stature and advanced bone age where more common causes have been eliminated. Although STK11 deletions are documented in control databases, reporting the deletion of this gene even in the absence of a phenotype is advised for patient management.

Sertoli Cell Tumour and Uterine Leiomyoma in Miniature Schnauzer Dogs with Persistent Müllerian Duct Syndrome Caused by Mutation in the AMHR2 Gene.

Disorders of sex development (DSD) are a serious health problem in dogs. Different types of DSD have been described, including persistent Müllerian duct syndrome (PMDS), for which the molecular background has been identified in miniature schnauzers. Human patients with PMDS are at increased risk for cancers of the gonads (predominantly) or the Müllerian duct structures (rarely). This report describes two miniature schnauzer dogs with PMDS caused by a known nonsense mutation in the AMHR2 gene, with concurrent development of genital neoplasia. The first case (78,XY and SRY-positive) had unilateral cryptorchidism and a Sertoli cell tumour in the abdominal testicle. The second case (mosaic karyotype 77,XY,rob/78,XY and SRY-positive) had both gonads descended in the scrotum and developed an abdominal mass derived from the uterine wall, which showed histological features typical of leiomyoma.

[Clinicopathologic and molecular characterizations of Sertoli cell tumor, not otherwise specified of the testis].

Objective: To investigate the histomorpholgic spectrum, immunophenotypic, and molecular genetic features of Sertoli cell tumor, not otherwise specified (SCT, NOS) of the testis. Methods: Seven cases of SCT, NOS of the testis were analyzed(4 from Peking University Third Hospital and 3 from Zhejiang Provincial People's Hospital) between 2008 and 2017. The histopathologic features were examined based on HE staining, and EnVision method was used for immunohistochemistry staining of calretinin, inhibin, ß-catenin, cyclinD1, CD10, CKpan, neuroendocrine markers, WT1, Melan A, vimentin, SALL4, GATA3, PAX8, and S-100 protein. Mutational analysis of exon 3 of the CTNNB1 gene by polymerase chain reaction (PCR)-amplified sequences and direct sequencing was performed. Results: Patients ages ranged from 22 to 65 years (mean 43 years). The clinical manifestation in all was a slowly enlarging, painless testicular mass.The maximum diameter of the tumor ranged from 1.5 cm to 3.0 cm (mean 2.1 cm). Sectioning usually disclosed a tan-gray to white mass with vague lobular cut-surface. Microscopically, the tumors were well circumscribed and non-encapsulated; the tumor cells were rearranged in multiple growth patterns from diffuse solid sheets to trabeculae and cords, ribbon and solid or hollow tubules setting in variable amount of acellular fibrous stroma. Two cases showed acellular collagenous stroma constituted >50% of the tumor confirming to the diagnosis of sclerosing SCT. One case demonstrated a prominent myxoid stromal change. The tumor cells typically had moderate amounts of pale to lightly eosinophilic cytoplasm, 2 tumors had variable cells with abundant lipid-rich cytoplasm, and 1 other tumor showed scattered aggregates of multinucleated tumor cells. The tumor cells were bland-appearing without any evidence of atypia, mitoses were noted in 2 tumors (both were 1/50 HPF), but necrosis was absent. Immunohistochemical staining results as follows: vimentin (diffuse, 7/7), CD10 (diffuse membrane, 7/7); diffuse ß-catenin nuclear and cytoplasm staining in 5 of 7 cases, and all the 5 cases showed diffuse cyclin D1 nuclear staining, ß-catenin membrane staining in 2 of 7 cases, CKpan (5/7, focal or diffuse), calretinin (focal, 5/6), inhibin (focal, 3/7), synaptophysin (focal, 2/6), CD56 (focal or diffuse, 4/5), WT1 (diffuse nuclear, 4/5), and S-100 protein (diffuse, 3/7), and chromogranin A, Melan A, PAX8, GATA3 and SALL4 all were negative. Molecular genetic studies of PCR and direct sequencing showed CTNNB1 mutations in 4 of 7 (4/7) cases, 4 of the four mutation-carrying cases showed diffuse ß-catenin nuclear and cytoplasm immunoreactivity and diffuse cyclin D1 nuclear immunoreactivity in the tumor cells. Conclusions: SCT, NOS of the testis typically shows significant heterogeneities in both morphology and immunohistochemistry, thus causing differential diagnostic confusions. Molecular analyses showed mutations of exon 3 of CTNNB1 in more than half of these tumors, and nuclear accumulation of ß-catenin and over expression of cyclin D1 can be useful for the differential diagnosis of SCT, NOS.

Expression patterns of HENMT1 and PIWIL1 in human testis: implications for transposon expression.

This study aimed to define the expression patterns of HENMT1 and PIWI proteins in human testis and investigate their association with transposon expression, infertility sub-type or development of testicular germ cell tumours (TGCTs). Testis biopsies showing normal spermatogenesis were used to identify normal localisation patterns of HENMT1 and PIWIL1 by immunolocalisation and RT-PCR after laser microdissection. 222 testis biopsies representing normal spermatogenesis, hypospermatogenesis, spermatogenic arrests, Sertoli cell-only (SCO) tumours and TGCTs were analysed by RT-qPCR for expression of HENMT1/PIWIL1/PIWIL2/PIWIL3/PIWIL4 and LINE-1 Additionally, HENMT1-overexpressing TCam2 seminoma cell lines were analysed for the same parameters by RT-qPCR. We found that HENMT1 and PIWIL1 are coexpressed in pachytene spermatocytes and spermatids. Expression of HENMT1, PIWIL1 and PIWIL2 was mainly dependent on germ cell content but low levels of expression were also detected in some SCO samples. Levels of HENMT1, PIWIL1 and PIWIL2 expression were low in TGCT. Samples with HENMT1, PIWIL2 and PIWIL4 expression showed significantly (P < 0.05) lower transposon expression compared to samples without expression in the same histological group. HENMT1-overexpressing TCam2 cells showed lower LINE-1 expression than empty vector-transfected control lines. Our findings support that the transposon-regulating function of the piRNA pathway found in the mouse is conserved in adult human testis. HENMT1 and PIWI proteins are expressed in a germ-cell-specific manner and required for transposon control.

An adolescent with large cell calcifying sertoli cell tumor of the testis and undiagnosed Carney Complex: A case report.

Carney Complex (CNC) is a rare autosomal dominant condition with characteristic clinical presentation, tumor development, and unique genetic mutation. We present a unique case and literature review of CNC in which two neoplasms characteristic of this complex were initially diagnosed through cytological fine needle aspirate specimens, leading to the identification of CNC, with subsequent surgical and cytogenetic confirmation. Diagn. Cytopathol. 2017;45:634-639. © 2017 Wiley Periodicals, Inc.

Suppression of Sertoli cell tumour development during the first wave of spermatogenesis in inhibin α-deficient mice.

A dynamic partnership between follicle-stimulating hormone (FSH) and activin is required for normal Sertoli cell development and fertility. Disruptions to this partnership trigger Sertoli cells to deviate from their normal developmental pathway, as observed in inhibin α-knockout (Inha-KO) mice, which feature Sertoli cell tumours in adulthood. Here, we identified the developmental windows by which adult Sertoli cell tumourigenesis is most FSH sensitive. FSH was suppressed for 7 days in Inha-KO mice and wild-type littermates during the 1st, 2nd or 4th week after birth and culled in the 5th week to assess the effect on adult Sertoli cell development. Tumour growth was profoundly reduced in adult Inha-KO mice in response to FSH suppression during Weeks 1 and 2, but not Week 4. Proliferative Sertoli cells were markedly reduced in adult Inha-KO mice following FSH suppression during Weeks 1, 2 or 4, resulting in levels similar to those in wild-type mice, with greatest effect observed at the 2 week time point. Apoptotic Sertoli cells increased in adult Inha-KO mice after FSH suppression during Week 4. In conclusion, acute FSH suppression during the 1st or 2nd week after birth in Inha-KO mice profoundly suppresses Sertoli cell tumour progression, probably by inhibiting proliferation in the adult, with early postnatal Sertoli cells being most sensitive to FSH action.

[Leydig cell, Sertoli cell and adult granulosa cell tumors]. / Leydig-Zell-, Sertoli-Zell- und adulte Granulosazelltumoren.

According to the World Health Organization (WHO) classification Leydig cell tumors, Sertoli cell tumors and granulosa cell tumors of the testes belong to the group of sex cord-stromal tumors. These tumors most frequently occur sporadically but in rare cases can be associated with syndromes. These tumor entities show characteristic morphological changes, which in combination with specific immunohistochemical markers facilitate the diagnosis. Recent results of molecular pathological investigations, especially beta-catenin mutation analysis, allow a better categorization of these tumor entities.

Unusual Sertoli Cell Tumor Associated With Sex Cord Tumor With Annular Tubules in Peutz-Jeghers Syndrome: Report of a Case and Review of the Literature on Ovarian Tumors in Peutz-Jeghers Syndrome.

We report the case of an 11-year-old girl with Peutz-Jeghers syndrome and a unilateral ovarian tumor most consistent with Sertoli cell tumor associated with sex cord tumor with annular tubules. The ovary was replaced by a lobular, solid, yellow tumor. Microscopic examination showed 2 components that focally merged. The first was composed of uniform, cytologically bland cells arranged mostly in diffuse sheets and focally in tubules. The second showed typical sex cord tumor with annular tubules with extensive calcification. The predominant component of the tumor clearly fell in the sex cord category and most closely resembled Sertoli cell tumor. This case adds to the limited information on ovarian sex cord tumors, other than typical sex cord tumor with annular tubules, arising in association with Peutz-Jeghers syndrome, a topic reviewed herein.

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.

[Sex cord gonadal stromal tumors]. / Tumoren des Gonadenstromas.

According to the World Health Organization (WHO) classification from 2004, sex cord gonadal stromal tumors are divided into Leydig cell tumors, Sertoli cell tumors, granulosa cell tumors, tumors of the thecoma-fibroma group, incompletely differentiated sex cord gonadal stromal tumors, mixed forms of sex cord gonadal stromal tumors and tumors containing both germ cell and sex cord gonadal stromal elements. These tumors can appear sporadically or in combination with hereditary syndromes. To diagnose these rare tumors the combination of characteristic morphological aspects and various immunohistochemical markers is useful. Latest investigations demonstrate the potential role of mutation analyses in the diagnosis of this heterogeneous group of tumors.

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.