Quantification of immunocompetent cells in testicular germ cell tumours

The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm² of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours ( P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours.     

Quantification of immunocompetent cells in testicular germ cell tumours

The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm² of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours (P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours.     

Bilateral incipient germ cell tumours of the testis in the incomplete testicular feminization syndrome

The presence of bilateral incipient germ cell tumours in the testes of two cases of the incomplete testicular feminization syndrome (TFS) is reported and found to resemble that occurring in the testes of infertile men. Both the nature and nomenclature of the lesion is discussed, as is its relevance in the early diagnosis and improved therapy of testicular tumours, which occur frequently in TFS. Suggestions are made for a more complete postpubertal surveillance in these patients, including assay of tumour markers and bilateral biopsies in cases of complete TFS. In this condition the removal of the testes is usually delayed until the twenties when total feminization is achieved, thus increasing the chances of tumour development.     

Molecular evidence supporting the neoplastic nature of odontogenic keratocyst: a laser capture microdissection study of 15 cases

AIMS: The bland histology of odontogenic keratocyst (OKC) belies its capacity for aggressive behaviour. Genetic alterations of OKC have not been well studied. We examined the frequency and pattern of allelic imbalance on five different chromosome regions from 15 patients with OKC. METHODS AND RESULTS: Laser-assisted microdissection was performed on formalin-fixed paraffin-embedded tissue. Polymerase chain reaction analysis of extracted DNA targeted five polymorphic DNA markers (D3S1285, D9S161, D11S1316, D13S290, and TP53) representing chromosome regions 3p14, 9p21, 11q23, 13q12.1 and 17p13, respectively. All 15 cases of OKC were informative at a minimum of three of five loci, with 11 informative on all five loci. Twelve of 15 cases (80%) demonstrated loss of heterozygosity (LOH). Seven cases (47%) showed LOH at more than two DNA loci. The frequency of LOH was 5/11 (45%) at D3S1285, 3/15 (20%) at D9S161, 4/14 (29%) at D11S1316, 8/14 (57%) at D13S290 and 3/15 (20%) at TP53. CONCLUSIONS: The majority of OKCs harbour chromosomal abnormalities. This finding supports the supposition that OKCs are neoplastic. Furthermore, OKCs harbour allelic loss at some of the same loci identified in squamous cell carcinoma. This may aid in explaining the rare occurrence of squamous cell carcinoma arising in OKC.     

Molecular genetic evidence supporting diverse histogenic origins of germ cell tumors

Germ cell tumors (GCTs) originate during the histogenesis of primordial germ cells to mature gametes. Previous studies identified five histogenic mechanisms in ovarian mature teratomas (type I: failure of meiosis I; type II: failure of meiosis II; type III: duplication of the genome of a mature gamete; type IV: no meiosis; and type V: fusion of two different ova), but those of other GCTs remain elusive. In this study, we analyzed 84 GCTs of various pathologic types to identify the histogenesis using single-nucleotide polymorphism array by analyzing copy-neutral loss of heterozygosity (CN-LOH) and copy number alterations (CNAs). We detected types I and II in ovarian teratomas, type III in ovarian teratomas and yolk sac tumors (YSTs), and type IV in all GCT types. The GCTs with multiple-type histogenesis (I–IV) (ovarian mature/immature teratomas and YST) show meiotic CN-LOH with scant CNAs. Type IV-only GCTs are either with mitotic CN-LOH and abundant CNAs (seminoma, dysgerminoma, testicular mixed GCTs) or with scant CNAs and no CN-LOH (pediatric testicular and mediastinal teratomas). The development sequences of CN-LOH and CNA are different between the multiple type (I–IV) GCTs and type IV-only GCTs. We analyzed two different histologic areas in eight GCTs (one mature teratoma with a mucin-secreting adenoma, two immature teratomas, and five mixed GCTs). We found that GCTs (mature teratoma, immature teratoma, and mixed GCT) showed different genomic alterations between histologic areas, suggesting that genomic differences within a GCT could accompany histologic differentiation. Of note, we found evidence for collision tumors in a mixed GCT. Our data indicate that GCTs may have various histogenesis and intratumoral genomic differences, which might provide important information for the identification of GCTs, especially for those with different histologic areas. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Loss of heterozygosity,differentiation, and clonality in microdissected male germ cell tumours

Testicular germ cell tumours (TGCTs) are heterogeneous neoplasms with different histological patterns and malignant potential. The aim of this study was to determine whether the main TGCT subtypes (seminoma, embryonal carcinoma, yolk sac tumour, choriocarcinoma, and mature teratoma) are distinguished by their loss of heterozygosity (LOH) patterns and whether LOH typing can help to distinguish between clonal and multifocal development of different components in mixed TGCTs. In 76 tumours analysed for allelic losses at 25 chromosomal loci, different LOH patterns were found in distinct histological subtypes. A region around D18S543 frequently lost in yolk sac tumours could harbour one or more tumour suppressor genes. In 20 microdissected mixed tumours, losses of identical alleles in different histological components in 11 of 20 cases (over 50 per cent) were found, which is in favour of current histogenetic models of clonal TGCT development. Clonal losses were most often found at D13S317 (6 of 20 tumours). Two classes of allelic losses may therefore occur during TGCT development: clonal losses which are involved in early transformational events and others related to TGCT differentiation along different lines. Copyright © 1999 John Wiley & Sons, Ltd.     

Histological evidence of testicular dysgenesis in contralateral biopsies from 218 patients with testicular germ cell cancer

This study was prompted by a hypothesis that testicular germ cell cancer may be aetiologically linked to other male reproductive abnormalities as a part of the so-called 'testicular dysgenesis syndrome' (TDS). To corroborate the hypothesis of a common association of germ cell cancer with testicular dysgenesis, microscopic dysgenetic features were quantified in contralateral testicular biopsies in patients with a testicular germ cell tumour. Two hundred and eighty consecutive contralateral testicular biopsies from Danish patients with testicular cancer diagnosed in 1998-2001 were evaluated retrospectively. Two hundred and eighteen specimens were subsequently included in this study, after 63 patients who did not meet inclusion criteria had to be excluded. The presence of carcinoma in situ (which is believed to originate from transformed gonocytes) was detected in 8.7% of biopsies. The incidence of other dysgenetic features was immature tubules with undifferentiated Sertoli cells, 4.6%; microcalcifications (microliths), 6.0%; and the presence of a Sertoli-cell-only pattern in at least a few tubules, 13.8%. The cumulative incidence of one or more signs of testicular dysgenesis was 25.2%. In a few patients, areas with immature and morphologically distorted tubules were also noted. Spermatogenesis was qualitatively normal in 51.4%, whereas 11.5% had very poor or absent spermatogenesis. It is concluded that microscopic testicular dysgenesis is a frequent feature in contralateral biopsies from patients presenting with testicular germ cell neoplasms of the adolescent and young type. The findings therefore support the hypothesis that this cancer is part of a testicular dysgenesis syndrome. The presence of contralateral carcinoma in situ was higher in the present study than previously reported.     

荧光原位杂交技术在纵隔原发生殖细胞肿瘤病理诊断中的价值

目的应用荧光原位杂交(fluorescence in situ hybridization,FISH)技术检测纵隔原发生殖细胞肿瘤(primary mediastinal germ cell tumors,PMGCTs)中12p获得的情况,探讨其在PMGCTs病理诊断中的价值。方法观察3例PMGCTs的临床病理特征,采用免疫组化En Vision法染色检测PMGCTs的免疫表型,应用FISH法检测肿瘤的12p获得情况。结果 3例PMGCTs均为男性,年龄22~24岁。CT示前纵隔占位,例3肿瘤广泛累及肺部。患者血清AFP和(或)β-hCG升高。2例肿瘤组织形态表现为单一精原细胞瘤或混合性生殖细胞肿瘤。免疫表型:SALL4、PLAP均阳性,其中精原细胞瘤成分表达CD117、OCT4,卵黄囊瘤表达AFP,胚胎癌表达CKpan、CD30。例3肿瘤分化差,免疫抗原显著丢失。FISH检测3例PMGCTs均存在i(12p)信号。结论青春期后非纯畸胎瘤PMGCTs发生12p获得,FISH检测纵隔肿瘤存在i(12p),具有重要的病理诊断价值。     

DNA content and expression of tumour markers in germ cells adjacent to germ cell tumours in childhood: Probably A different origin for infantile and adolescent germ cell tumours

The origin of testicular germ cell tumours occurring during childhood is poorly understood. In adults, the classical seminomas and non-seminomas originate from carcinoma in situ of the testis, which can usually also be detected in seminiferous tubules adjacent to the tumours. In order to contribute with information regarding a possible association between carcinoma in situ and the childhood group of germ cell tumours, we investigated seminiferous tubules adjacent to 13 infantile yolk sac tumours, five infantile teratomas, and six adolescent germ cell tumours of various types, using morphological evaluation, immunohistochemical staining with markers for carcinoma in situ cells, and densitometric DNA measurement of the germ cells. We detected clear differences between the germ cell populations adjacent to adolescent and infantile germ cell tumours. The former were associated with both normal germ cells and carcinoma in situ cells. The presence of carcinoma in situ cells strongly suggested that the adolescent tumours arose from carcinoma in situ cells, like germ cell tumours occurring in adult men. Although we were in doubt in two cases, the infantile germ cell tumours were in general not associated with carcinoma in situ cells. The aetiology of infantile yolk sac tumours and teratomas may therefore be fundamentally different from that of adolescent and adult germ cell tumours. The origin of yolk sac tumours and teratomas remains to be elucidated.     

Germ cell neoplasia in situ (GCNIS): evolution of the current nomenclature for testicular pre‐invasive germ cell malignancy

The pre‐invasive lesion associated with post‐pubertal malignant germ cell tumours of the testis was first recognized in the early 1970s and confirmed by a number of observational and follow‐up studies. Until this year, this scientific story has been confused by resistance to the entity and disagreement on its name. Initially termed ‘carcinoma in situ’ (CIS), it has also been known as ‘intratubular germ cell neoplasia, unclassified’ (IGCNU) and ‘testicular intraepithelial neoplasia’ (TIN). In this paper, we review the history of discovery and controversy concerning these names and introduce the reasoning for uniting behind a new name, endorsed unanimously at the World Health Organization (WHO) consensus classification 2016: germ cell neoplasia in situ (GCNIS).     

The World Health Organization 2016 classification of testicular germ cell tumours: a review and update from the International Society of Urological Pathology Testis Consultation Panel

Since the last World Health Organization (WHO) classification scheme for tumours of the urinary tract and male genital organs, there have been a number of advances in the understanding, classification, immunohistochemistry and genetics of testicular germ cell tumours. The updated 2016 draft classification was discussed at an International Society of Urological Pathology Consultation on Testicular and Penile Cancer. This review addresses the main updates to germ cell tumour classification. Major changes include a pathogenetically derived classification using germ cell neoplasia in situ (GCNIS) as a new name for the precursor lesion, and the distinction of prepubertal tumours (non‐GCNIS‐derived) from postpubertal‐type tumours (GCNIS‐derived), acknowledging the existence of rare benign prepubertal‐type teratomas in the postpubertal testis. Spermatocytic tumour is adopted as a replacement for spermatocytic seminoma, to avoid potential confusion with the unrelated usual seminoma. The spectrum of trophoblastic tumours arising in the setting of testicular germ cell tumour continues to expand, to include epithelioid and placental site trophoblastic tumours analogous to those of the gynaecological tract. Currently, reporting of anaplasia (seminoma or spermatocytic tumour) or immaturity (teratoma) is not required, as these do not have demonstrable prognostic importance. In contrast, overgrowth of a teratomatous component (somatic‐type malignancy) and sarcomatous change in spermatocytic tumour indicate more aggressive behaviour, and should be reported.     

Developmental model for the pathogenesis of testicular carcinoma in situ: genetic and environmental aspects

Carcinoma in situ testis (CIS), also known as intratubular germ cell neoplasia (ITGCN), is a pre-invasive precursor of testicular germ cell tumours, the commonest cancer type of male adolescents and young adults. In this review, evidence supporting the hypothesis of developmental origin of testicular germ cell cancer is summarized, and the current concepts regarding aetiology and pathogenesis of this disease are critically discussed. Comparative studies of cell surface proteins (e.g. PLAP and KIT), some of the germ cell-specific markers (e.g. MAGEA4, VASA, TSPY and NY-ESO-1), supported by studies of regulatory elements of the cell cycle (e.g. p53, CHK2 and p19-INK4d) demonstrated a close similarity of CIS to primordial germ cells and gonocytes, consistent with the pre-meiotic origin of CIS. Recent gene expression profiling studies showed that CIS cells closely resemble embryonic stem cells (ESCs). The abundance of factors associated with pluripotency (NANOG and OCT-3/4) and undifferentiated state (AP-2gamma) may explain the remarkable pluripotency of germ cell neoplasms, which are capable of differentiating to various somatic tissue components of teratomas. Impaired gonadal development resulting in the arrest of gonocyte differentiation and retention of its embryonic features, associated with an increasing genomic instability, is the most probable model for the pathogenesis of CIS. Genomic amplification of certain chromosomal regions, e.g. 12p, may facilitate survival of CIS and further invasive progression. Genetic studies, have so far not identified gene polymorphisms predisposing to the most common non-familial testicular cancer, but this research has only recently begun. Association of CIS with other disorders, such as congenital genital malformations and some forms of impaired spermatogenesis, all rising in incidence in a synchronous manner, led to the hypothesis that CIS might be a manifestation of testicular dysgenesis syndrome (TDS). The aetiology of TDS including testicular cancer remains to be elucidated, but epidemiological trends suggest a primary role for environmental factors, probably combined with genetic susceptibility.     

Constant allelic alteration on chromosome 16p (TSC2 gene) in perivascular epithelioid cell tumour (PEComa): genetic evidence for the relationship of PEComa with angiomyolipoma

Perivascular epithelioid cell tumours (PEComas) are a family of tumours including classic angiomyolipoma, lymphangioleiomyomatosis, and clear epithelioid cell tumours reported under a variety of names such as epithelioid angiomyolipoma, pulmonary and extrapulmonary clear cell sugar tumour, and PEComa. Our previous comparative genomic hybridization study of PEComas demonstrated recurrent chromosomal aberrations including deletions on chromosome 16p, where the TSC2 gene is located. In this study, we focused on the alteration of chromosome 16p, including TSC2. We collected ten sporadic and two tuberous sclerosis complex-associated PEComas, as well as 14 sporadic classic hepatic and renal angiomyolipomas (AMLs) as controls. We used 16 microsatellite markers distributed along chromosome 16p to test for allelic imbalances on chromosome 16p and at TSC2, and two markers for TSC1. Furthermore, we carried out immunohistochemical staining for phospho-p706K, phospho-AKT, and phospho-S6 to evaluate the effect of TSC2 alterations on the mTOR signalling pathway. Loss of heterozygosity (LOH) was found in 11 PEComas and involved the region of the TSC2 locus in seven. Six classic angiomyolipomas had allelic changes at chromosome 16p. Microsatellite instability was detected in two PEComas. The incidence of genetic aberrations was significantly higher in the PEComa group. Only one PEComa showed LOH at the TSC1 locus. Eleven PEComas and 13 AMLs revealed elevated phospho-p70S6K accompanied by reduced phospho-AKT. Five PEComas and eight classic angiomyolipomas were positive for phospho-S6. The phosphorylation profile indicates functional activation of the mTOR pathway through a disrupted TSC1/2 complex. Our observations of frequent deletion of TSC2 and the mTOR signalling pathway provide evidence that the oncogenetic lineage of PEComa, as a distinct TSC2-linked neoplasm, is similar to that of angiomyolipoma.     

Identification of germ cells at risk for neoplastic transformation in gonadoblastoma: an immunohistochemical study for OCT3/4 and TSPY

Carcinoma in situ (CIS) is the precursor of malignant testicular germ cell tumors (GCTs) of adolescents and young adults, being the neoplastic counterpart of primordial germ cells/gonocytes. Carcinoma in situ cells will develop into invasive seminoma/nonseminoma. Gonadoblastoma (GB) is the precursor of invasive GCTs in dysgenetic gonads, predominantly dysgerminoma (DG). In this process, part of the Y chromosome (GBY region) is involved, for which TSPY is a candidate gene. A detailed immunohistochemical survey was performed for the known diagnostic markers, germ cell/placental alkaline phosphatase (PLAP), c-KIT, and OCT3/4, as well as testis-specific protein on the Y chromosome (TSPY) on a series of GBs, and adjacent invasive DGs. All 5 patients were XY individuals (4 females and 1 male). In contrast to c-KIT, PLAP was positive in all cases. The immature germ cells of GBs were positive for OCT3/4, whereas the mature germ cells were negative for this marker, but positive for TSPY. In every GB, a minor population of germ cells positive for both markers could be identified, similar to most CIS cells and early invasive DG. On progression to an invasive tumor, TSPY can be lost, a process that is also detectable in invasive testicular GCTs compared to CIS. These results indicate that GB is a heterogeneous mix of germ cells, in which the OCT3/4-positive cells have the potential to undergo progression to an invasive tumor. These early invasive stages are initially also positive for TSPY (like CIS), supporting a positive selection mechanism. Therefore, OCT3/4 in combination with TSPY is valuable to identify malignant germ cells in dysgenetic gonads. This could allow better prediction of the risk of progression to a GCT. In addition, the data support the model that GB represents the earliest accessible developmental stage of malignant GCTs.