Evolution of Testicular Germ Cell Tumors in the Molecular Era With Histogenetic Implications.

The current WHO classification of testicular germ cell tumors is based on the pathogenesis of the tumors driven by different genomic events. The germ cell neoplasia in situ is the precursor lesion for all malignant germ cell tumors. The current understanding of pathogenesis is that the developmental and environmental factors with the erasure of parental genomic imprinting lead to the development of abnormal gonocytes that settle in the "spermatogonial Niche" in seminiferous tubules. The abnormal primordial germ cells in the seminiferous tubules give rise to pre-GCNIS cells under the influence of TPSY and OCT4 genes. The whole genome duplication events give rise to germ cell neoplasia in situ, which further acquires alterations in 12p along with NRAS and KRAS mutations to produce seminoma. A subset of seminomas acquires KIT mutation and does not differentiate further. The remaining KIT-stable seminomas differentiate to nonseminomatous GCTs after obtaining recurrent chromosomal losses, epigenetic modification, and posttranscriptional regulation by multiple genes. Nonseminomatous germ cell tumors also develop directly from differentiated germ cell neoplasia in situ. TP53 pathway with downstream drivers may give rise to somatic-type malignancies of GCT. The GCTs are remarkably sensitive to cisplatin-based combination chemotherapy; however, resistance to cisplatin develops in up to 8% of tumors and appears to be driven by TP53/MDM2 gene mutations. Serum and Plasma miRNAs show promise in diagnosing, managing, and following up on these tumors. The mechanisms underlying the development of most tumors have been elucidated; however, additional studies are required to pinpoint the events directing specific characteristics. Advances in identifying specific molecular markers have been seen recently and may be adopted as gold standards in the future.

Primary testicular teratoid Wilms tumor in a 40-year-old male with retroperitoneal lymph node involvement: A case report.

We report a 40-year-old male presenting with right testicular pain. Following right orchiectomy demonstrating pT1bS0N0M0 teratoma with extensive necrosis, the patient opted for surveillance. With new retroperitoneal lymphadenopathy, the patient underwent a robotic-assisted laparoscopic retroperitoneal lymph node. After final pathology demonstrated extensive necrosis, the initial orchiectomy specimen was re-reviewed which revealed 60/40 ratio of non-seminomatous teratoma to nephroblastoma. Adult presentation of testicular nephroblastoma is exceedingly rare and such reports contribute to the understanding of adult teratoid Wilms tumor pathogenesis. This case emphasizes the need for comprehensive diagnostic approaches and further research into the pathophysiology of extrarenal teratoid Wilms tumors.

P53 Overexpression May Represent an Early Marker of Clinicopathologic Progression in Vasculogenic Mesenchymal Lesions of Germ Cell Tumor Origin.

Vasculogenic mesenchymal lesions (VMLs) of germ cell tumor origin are thought to originate in postpubertal-type yolk sac tumor components and include a spectrum of lesions from teratoma with vasculogenic stroma (TVS), to low and high-grade vasculogenic mesenchymal tumors (VMTs). VMLs exhibit rudimentary to well-developed neoplastic vessels within primitive mesenchyme, being considered a neoplastic reiteration of embryonic vasculogenesis in the splanchnic mesoderm of the yolk sac. They occur in patients with primary mediastinal germ cell tumors after chemotherapy, and a subset progresses to "somatic-type" sarcomas [including angiosarcoma (AS)], with high-grade VMTs likely portending a higher risk. Recently, we encountered a low-grade VMT that progressed to metastatic AS during follow-up. In this case, both the low-grade VMT and the subsequent AS demonstrated p53 overexpression, suggesting that p53 alterations may precede histopathologic transformation. To test this hypothesis, we evaluated neoplasms representing the entire spectrum of VMLs using p53 immunohistochemistry (IHC; clone DO-7, Dako). Overexpression was defined as nuclear positivity in > 80% of neoplastic cells. Because the distinction between high-grade VMT and AS can be subjective in some cases, they were grouped together in a single category. Thirty-nine VMLs were assessed: 16 high-grade VMT/AS, 19 low-grade VMT, and 4 TVS. Patient age ranged from 19 to 46 years (mean, 30 years; male = 97%). Four high-grade VMT/AS and one low-grade VMT showed p53 overexpression (5/39 VMLs, 13%; 4/16 high-grade VMT/AS, 25%). These tumors included 1 unequivocal AS and 1 high-grade VMT/AS with progression to rhabdomyosarcoma. The only low-grade VMT with p53 overexpression demonstrated progression to AS. Another high-grade VMT that progressed to sarcoma demonstrated p53 overexpression in the sarcoma component, but it was excluded because the VMT was not represented in the material available at the time of the study. Lesions with intratumoral grade heterogeneity (classified based the highest grade), demonstrated more pronounced p53 overexpression in the high-grade components. P53 overexpression is associated with disease progression in a subset of VMTs and may precede morphologic transformation to sarcoma. Routine evaluation of VMTs with p53 IHC seems justified, with overexpressors likely requiring an close clinical surveillance.

Genomic analysis of primary epithelial neoplasms of the seminal vesicle identifies a subset of mucinous cystic tumours driven by KRAS mutations.

BACKGROUND: Carcinomas of the seminal vesicle are exceedingly rare, with a limited number of cases described in the literature. Reported cases span a relatively wide morphological spectrum, and their genomic features remain unexplored. DESIGN: In this study, we interrogated five primary epithelial neoplasms of the seminal vesicle using a targeted DNA sequencing platform (OncoPanel, 447 genes). RESULTS: The tumours included one adenocarcinoma with intestinal phenotype presenting after external beam radiation (for prostatic adenocarcinoma), one carcinoma with Müllerian-type clear cell phenotype, two mucinous tumours resembling low-grade mucinous neoplasms of the appendix (LAMN) and one mucinous cystadenoma. The post-radiation mucinous adenocarcinoma had genomic findings consistent with bi-allelic inactivation of TP53, as well as multiple copy-number changes with regional and chromosomal arm-level copy-number losses. The Müllerian-type clear cell carcinoma exhibited a complex copy-number profile with numerous regional and arm-level copy-number changes, as well as focal amplification events, including copy-number gain of 8q and amplification of a region within 20q13. Both low-grade mucinous tumours resembling LAMN harboured hot-spot gain-of-function KRAS variants (p.G12V and p.G13D) as the only genomic alteration. No genomic alterations were detected inthe lesion diagnosed as mucinous cystadenoma. CONCLUSION: Our results suggest that primary low-grade mucinous neoplasms of the seminal vesicle may represent a distinct entity equivalent to appendiceal counterparts, driven by gain-of-function variants of RAS GTPases. The remaining tumours showed genomic features that closely resembled those of neoplasms with comparable phenotypes and/or biological characteristics arising in other sites, suggesting that they could be managed similarly, with special considerations related to their anatomical location.

Biphasic papillary (biphasic squamoid alveolar) renal cell carcinoma: a clinicopathologic and molecular study of 17 renal cell carcinomas including 10 papillary adenomas.

Biphasic papillary renal cell carcinoma (synonymous with biphasic squamoid alveolar renal cell carcinoma) is considered within the spectrum of papillary renal cell carcinoma (PRCC). With < 70 reported cases of biphasic PRCC, there is limited data on the pathologic spectrum and clinical course. Seventeen biphasic PRCC cases and 10 papillary adenomas with similar biphasic morphology were assessed. The mean age of the biphasic PRCC patients was 62 years (male to female ratio of 1.8:1), from 10 partial nephrectomies, 6 radical nephrectomies, and 1 biopsy. The mean tumor size was 3.6 cm (range 1.6-8 cm), with 24% showing multifocality. Fifteen out of 17 cases were limited to the kidney (one of which was staged as pT2a but had lung metastases at diagnosis) and 2/17 cases were staged as T3a. All tumors showed typical biphasic morphology with an extent of squamoid foci widely variable from 10 to 95%. Emperipolesis was identified in 88% of cases. All biphasic PRCC tested exhibited positivity for PAX8 (16/16), keratin 7 (17/17), EMA (15/15), AMACR (17/17), and vimentin (12/12) in both large and small cells; cyclin D1 was only expressed in the large cells (16/16). The 10 papillary adenomas showed a similar immunoprofile to biphasic PRCC. NGS testing performed on 13 biphasic PRCC revealed 4 (31%) harboring MET SNVs. In 1/5 (20%) papillary adenomas, a pathogenic MET SNV was identified. Biphasic PRCC is rare with a generally similar immunoprofile to "type 1" PRCC but with notable strong positivity for cyclin D1 in the large cell component. Although most of the biphasic PRCC cases were of small size, low stage, and with an indolent behavior, one patient had metastatic disease and one patient died of the disease.

Giant bilateral prepubertal-type teratomas in a postpubertal patient: An illustrative case and review of the literature.

Prepubertal-type teratomas are uncommon, especially in postpubertal male patients. We document a case of a 28-year-old man with a lifelong history of bilateral testicular masses who presented with scrotal fistulas and no clinical evidence of extratesticular disease. Bilateral radical orchiectomies demonstrated large bilateral solid and cystic masses that contained grossly visible hairs. Microscopically, both tumors consisted of pure teratomas comprising a mixture of mature tissues derived from the three embryonic layers. Germ cell neoplasia in situ was not identified, and fluorescence in situ hybridization studies demonstrated the absence of i(12p), supporting a diagnosis of prepubertal-type teratoma. The absence of metastases in this patient with longstanding tumors highlights the benign nature of prepubertal-type teratomas affecting postpubertal patients. Furthermore, this case illustrates that at least a subset of prepubertal-type teratomas seen in adult men represent a late diagnosis of a largely pediatric entity. Additionally, we performed a comprehensive review of the literature on this topic.

Genetic Profiling Uncovers Genome-Wide Loss of Heterozygosity and Provides Insight into Mechanisms of Sarcomatoid Transformation in Chromophobe Renal Cell Carcinoma.

Sarcomatoid transformation occurs in ∼8% of chromophobe renal cell carcinoma (chRCC) and is associated with aggressive clinical behavior. In recent years, several studies have identified genomic, transcriptomic, and epigenomic correlates of aggressive behavior in chRCC; however, the molecular mechanisms associated with sarcomatoid transformation remain incompletely understood. In this study, we analyzed paired conventional and sarcomatoid histologic components of individual chRCC to elucidate the genomic alterations that underlie sarcomatoid transformation in this tumor type. Massively parallel sequencing was performed on paired (conventional and sarcomatoid) components from 8 chRCCs. All cases harbored TP53 variants (87.5% showing TP53 variants in both components and 12.5% only in the sarcomatoid component). Intratumor comparisons revealed that TP53 variants were concordant in 71% and discordant in 29% of cases. Additional recurrent single-nucleotide variants were found in RB1 (37.5% of cases) and PTEN (25% of cases), with the remaining single-nucleotide variants detected in these tumors (PBRM1, NF1, and ASXL1) being nonrecurrent. Copy number variant analysis showed the characteristic pattern of chromosomal losses associated with chRCC (1, 2, 6, 10, 13, 17, and 21) in the conventional histologic components only. Interestingly, the sarcomatoid components of these tumors demonstrated widespread loss of heterozygosity but lacked the above chromosomal losses, likely as a consequence of whole-genome duplication/imbalanced chromosomal duplication events. Overall, the findings suggest that TP53 variants followed by whole-genome duplication/imbalanced chromosomal duplication events underlie sarcomatoid transformation in chRCC.

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.

Testicular Neoplasms With Sex Cord and Stromal Components Harbor a Recurrent Pattern of Chromosomal Gains.

A small subset of testicular sex cord-stromal tumors, designated as Sertoli-stromal cell tumors (SSCTs), comprises a mixture of Sertoli, spindle, and/or Leydig cells. The clinicopathologic features of these tumors have not been studied in any detail, and their molecular features are unknown. We, therefore, assessed the morphologic and genomic features of 14 SSCTs, including 1 tumor with features similar to the ovarian Sertoli-Leydig cell tumor (SLCT) with retiform tubules. The median age of the patients was 24 years (range, 10-55 years), and the median tumor size was 2.3 cm (range, 0.7-4.7 cm). All tumors showed Sertoli-like sex cord cells arranged in variably developed tubular structures, typically also forming nests and cords. These imperceptibly blended with a neoplastic spindle cell stroma or, in the SLCT, vacuolated to eosinophilic Leydig cells. Genomic analysis demonstrated the presence of a hotspot loss-of-function DICER1 mutation in the SLCT (patient 1) and hotspot gain-of-function CTNNB1 mutations in the tumors of patients 2 and 3, with both CTNNB1 variants being interpreted as possible subclonal events. The mutations were the only relevant findings in the tumors of patients 1 and 2, whereas the tumor of patient 3 harbored concurrent chromosomal arm-level and chromosome-level copy number gains. Among the remaining 11 tumors, all of those that had interpretable copy number data (9 tumors) harbored multiple recurrent chromosomal arm-level and chromosome-level copy number gains suggestive of a shift in ploidy without concurrent pathogenic mutations. The results of the present study suggest that CTNNB1 mutations (likely subclonal) are only rarely present in SSCTs; instead, most of them harbor genomic alterations similar to those seen in testicular sex cord-stromal tumors with pure or predominant spindle cell components. A notable exception was a testicular SLCT with morphologic features identical to the ovarian counterpart, which harbored a DICER1 mutation.

Germline APC Alterations May Predispose to Testicular Sex Cord-Stromal Tumors.

Sertoli cell tumor is a type of testicular sex cord-stromal tumor (TSCST) typically driven by gain-of-function CTNNB1 variants. Recently, molecular studies have identified TSCSTs (including Sertoli cell tumors) with loss-of-function APC variants, raising the possibility that germline APC alterations may predispose to TSCSTs. In this study, we evaluated 4 TSCSTs from 4 individual patients, including 3 APC -mutant neoplasms identified in prior studies (1 in a patient with familial adenomatous polyposis [FAP] and 2 in patients with unknown syndromic status) and 1 tumor of unknown mutational status diagnosed in a patient with known FAP. Three neoplasms were typical Sertoli cell tumors, and 1 was a malignant unclassified TSCT. All neoplasms exhibited diffuse nuclear beta-catenin expression. Non-neoplastic tissue could be obtained for DNA sequencing in the 3 Sertoli cell tumors. Comparative assessment of non-neoplastic and lesional tissue in these cases suggested that germline APC variants with subsequent inactivation of the gene (loss of heterozygosity) were the likely oncogenic driver of these Sertoli cell tumors. In the malignant unclassified TSCSTs, APC inactivation was also interpreted as the most likely driver event, and the germline origin of the variant was inferred using a recently published method. The results of this study suggest that pathogenic germline APC alterations (eg, FAP and variants thereof) may predispose to TSCSTs.

Molecular Biomarkers With Potential Clinical Application in Testicular Cancer.

Testicular germ cell tumors (TGCTs) and sex cord-stromal tumors (SCSTs) are the most common testicular neoplasms. The morphologic spectrum of such tumors is wide, with several histologic subtypes within each group. Testicular tumors often represent a diagnostic challenge, requiring proper identification of their biologic potential for accurate risk stratification and selection of therapy. In the era of precision medicine, molecular biomarkers are increasingly assuming a critical role in the management of patients with cancer. Given the overall rarity of certain types of testicular neoplasms, progress in biomarker research has been relatively slow. However, in recent years, we have witnessed a multitude of important contributions, including both tissue-based and liquid biopsy biomarkers, stemming from important discoveries of tumor pathobiology, accurate histopathological analysis, multi-institutional studies, and genome-wide molecular analyses of specific tumor subtypes. In this review, we provide an overview of the progress in molecular biomarkers of TGCTs and SCSTs, focusing on those with greatest potential for clinical application. In TGCTs, developmental biology has been the key to understanding these tumors and identifying clinically useful biomarkers (from classical serum tumor markers to pluripotency factors and circulating microRNAs of the 371-373 cluster). For SCSTs, studies have focused on tissue biomarkers only, and genome-wide investigations have recently contributed to a better understanding of rare phenotypes and the aggressive biological behavior of some tumors within this nosologic category. Several new biomarkers are moving toward clinical implementation in this field. Therefore, the practicing pathologist should be aware of their strengths and limitations in order to utilize them properly and maximize their clinical benefits.

Metastatic solid tumors to the testis: a clinicopathologic evaluation of 157 cases from an international collaboration.

To elucidate the spectrum of metastatic solid tumors to the testis and their clinicopathologic features. The databases and files of 26 pathology departments from 9 countries on 3 continents were surveyed to identify metastatic solid tumors to the testis and to characterize their clinicopathologic features in detail. We compiled a series of 157 cases of metastatic solid tumors that secondarily involved the testis. The mean patient age at diagnosis was 64 years (range, 12-93 years). Most patients (127/144; 88%) had clinical manifestation of the disease, with testicular mass/nodule (89/127; 70%) being the most common finding. The main mechanism of testicular involvement was metastasis in 154/157 (98%) cases. Bilateral testicular involvement was present in 12/157 (8%) patients. Concurrent or prior extratesticular metastases were present in 78/101 (77%) patients. The diagnosis was made mainly in orchiectomy specimens (150/157; 95%). Different types of carcinomas (138/157; 87%), most commonly adenocarcinoma (72/157; 46%), were the most common malignancies. The most common primary carcinomas included prostatic (51/149; 34%), renal (29/149; 20%), and colorectal (13/149; 9%). Intratubular growth was identified in 13/124 (11%) cases and paratesticular involvement was found in 73/152 (48%) cases. In patients with available follow-up (110/157; 70%), more than half (58/110; 53%) died of disease. In this largest series compiled to date, we found that most secondary tumors of the testis represent metastases from the genitourinary and gastrointestinal tract carcinomas and typically occur in the setting of disseminated disease.

Concordance of MTOR Pathway Mutations and the Diagnosis of Renal Low-Grade Oncocytic Tumor (LOT).

The differential diagnosis for oncocytic renal tumors spans the spectrum from benign entities to more aggressive renal cell carcinomas (RCC). Recent work has characterized a provisional renal oncocytic neoplasm, namely the low-grade oncocytic tumor (LOT), which demonstrates overlapping morphologic features with oncocytoma and chromophobe RCC, but also has a unique immunoprofile (ie, diffusely positive for KRT7, negative for KIT) and a high rate (80% to 100%) of mTOR pathway gene alterations. Given the diagnostic overlap among oncocytic tumors, we looked for concordance between mTOR pathway mutations and LOT. Thirty low-grade renal oncocytic neoplasms underwent histologic review and immunohistochemistry for KRT7 and KIT. Tumors were classified as "determinate" (eg, LOT) for tumors with solid, nested or vaguely tubular growth and diffuse KRT7 staining and negative KIT, or "indeterminate" if the morphology and/or immunostains did not fully support a definitive LOT diagnosis. Next-generation sequencing was performed without any knowledge of the diagnoses, and identified mTOR pathway mutations in 80% (12/15) of the determinate tumors, compared with 7% (1/15) in the indeterminate group. One determinate tumor was reclassified as papillary RCC (MTOR mutation negative) and 6 indeterminate tumors were confirmed to be oncocytoma (N = 4), clear cell RCC or papillary RCC with reverse polarity, respectively. Overall, integration of morphology, immunohistochemistry, and molecular data enabled a final definitive diagnosis for 70% of tumors (21 of the total 30), with a high concordance (93%) for LOT specifically in the determinate group; the remaining 9 tumors (30%) were classified as renal oncocytic neoplasm, not otherwise specified.

Metastatic solid tumours to the penis: a clinicopathologic evaluation of 109 cases from an international collaboration.

AIMS: To elucidate the spectrum of metastatic tumours to the penis and their clinicopathologic features. METHODS: The databases and files of 22 pathology departments from eight countries on three continents were queried to identify metastatic solid tumours of the penis and to characterize their clinical and pathologic features. RESULTS: We compiled a series of 109 cases of metastatic solid tumours that secondarily involved the penis. The mean patient age at diagnosis was 71 years (range, 7-94 years). Clinical presentation commonly included a penile nodule/mass (48/95; 51%) and localised pain (14/95; 15%). A prior history of malignancy was known in 92/104 (89%) patients. Diagnosis was made mainly on biopsy (82/109; 75%), or penectomy (21/109; 19%) specimens. The most common penile locations were the glans (45/98; 46%) and corpus cavernosum (39/98; 39%). The most frequent histologic type was adenocarcinoma (56%). Most primary carcinomas originated in the genitourinary (76/108; 70%) and gastrointestinal (20/108; 18%) tracts, including prostate (38/108; 35%), urinary bladder (27/108; 25%), and colon/rectum (18/108; 17%). Concurrent or prior extrapenile metastases were identified in 50/78 (64%) patients. Clinical follow-up (mean 22 months, range 0-171 months) was available for 87/109 (80%) patients, of whom 46 (53%) died of disease. CONCLUSION: This is the largest study to date of metastatic solid tumours secondarily involving the penis. The most frequent primaries originated from the genitourinary and gastrointestinal tracts. Metastatic penile tumours usually presented with penile nodules/masses and pain, and they often occurred in the setting of advanced metastatic disease, portending poor clinical outcomes.

Cribriform morphology is associated with higher risk of biochemical recurrence after radical prostatectomy in patients with Grade Group 5 prostate cancer.

AIMS: Grade Group 5 (GG5) prostate cancer (PCa) is associated with a high risk of disease recurrence after radical prostatectomy (~75% at 5 years). However, this is a heterogeneous category that includes neoplasms with different combinations of Gleason pattern (GP) 4 and 5. Within GP4, large cribriform growth has been associated with adverse disease-specific outcomes in GG2-4 PCa. Less is known about the significance of cribriform morphology and the different histologic patterns of GP5 in GG5 PCa. METHODS AND RESULTS: In this study we evaluated the prognostic implications of cribriform morphology (either invasive or intraductal, henceforth "cribriform") and large solid growth or comedonecrosis (comedo/solid) in patients with GG5 PCa. One-hundred and thirty prostatectomies from a single institution were analysed. The presence of comedo/solid components was associated with a higher frequency of concurrent cribriform PCa (85.7% versus 45.9%, P < 0.001), lymphovascular invasion (44.6% versus 27%, P = 0.04), and biochemical recurrence (48.2% versus 28.4%, P = 0.03). The presence of large cribriform growth was associated with a higher frequency of extraprostatic involvement (i.e. pT3a-b; 85.3% versus 68.7%, P = 0.02), positive surgical margins (47.6% versus 29.2%, P = 0.04) and biochemical recurrence (47.6% versus. 18.7%, P = 0.001). Kaplan-Meier analysis demonstrated that GG5 PCa with cribriform or comedo/solid components had a higher probability of biochemical recurrence. Multivariable analysis showed that only cribriform components were an independent predictor of a higher risk of biochemical recurrence in this series. CONCLUSION: These findings highlight the importance of reporting the presence of cribriform components in GG5 PCa and suggest that cribriform morphology might help decide postsurgical management in these patients.