Mixed germ cell-sex cord stromal tumour of the testis and ovary: comparison and contrast.

Mixed germ cell-sex cord stromal tumours (MGC-SCSTs) of the testis and ovary differ significantly in their histological appearance, clinical behaviour, and molecular genetics. Until recently, the germ cells of testicular MGC-SCST were considered to be invariably histologically bland, whereas those from neoplasms that arise in the ovary have histological features characteristic of premalignancy. However, a recent histological and molecular genetic study demonstrated histological abnormalities and multiple chromosomal losses and gains in a small subset of testicular cases, thus providing the first evidence that testicular MGC-SCSTs can exceptionally show histological and molecular abnormalities. All cases of testicular MGC-SCST reported to date have been clinically benign, whereas ovarian examples are sometimes the precursor of a malignant germ cell neoplasm that can be clinically aggressive. Both genetic and epigenetic influences likely account for dissimilarities in these uncommon gonadal neoplasms.

Achieving flexible competence: bridging the investment dichotomy between infectious diseases and cancer.

Today's global health challenges in underserved communities include the growing burden of cancer and other non-communicable diseases (NCDs); infectious diseases (IDs) with epidemic and pandemic potential such as COVID-19; and health effects from catastrophic 'all hazards' disasters including natural, industrial or terrorist incidents. Healthcare disparities in low-income and middle-income countries and in some rural areas in developed countries make it a challenge to mitigate these health, socioeconomic and political consequences on our globalised society. As with IDs, cancer requires rapid intervention and its effective medical management and prevention encompasses the other major NCDs. Furthermore, the technology and clinical capability for cancer care enables management of NCDs and IDs. Global health initiatives that call for action to address IDs and cancer often focus on each problem separately, or consider cancer care only a downstream investment to primary care, missing opportunities to leverage investments that could support broader capacity-building. From our experience in health disparities, disaster preparedness, government policy and healthcare systems we have initiated an approach we call flex-competence which emphasises a systems approach from the outset of program building that integrates investment among IDs, cancer, NCDs and disaster preparedness to improve overall healthcare for the local community. This approach builds on trusted partnerships, multi-level strategies and a healthcare infrastructure providing surge capacities to more rapidly respond to and manage a wide range of changing public health threats.

Gonadoblastoma versus ovarian mixed germ cell-sex cord stromal tumor in women or girls with no evidence of a disorder of sex development: A problem in differential diagnosis.

Gonadoblastoma occurring in a normal girl or woman has been confused with ovarian mixed germ cell-sex cord stromal tumor (MGC-SCST) due to a lack of knowledge that the former occurs occasionally in a normal woman or girl. In this article, we develop histological criteria that facilitate the distinction of gonadoblastoma in an individual with a normal karyotype and no evidence of a disorder of sex development from ovarian MGC-SCST. We reviewed the histological findings of gonadoblastoma occurring in normal individuals and compared them to cases of ovarian MGC-SCST in our files. The histological findings of gonadoblastoma differ substantially from those of ovarian MGC-SCST. Importantly, gonadoblastoma contains two types of transformed germ cells, some histologically benign and others premalignant, whereas MGC-SCST contains only a single type, typically premalignant in the ovary and benign in the testis. Furthermore, degenerative changes of hyalinization and calcification are common in gonadoblastoma, whereas they are extremely rare in MGC-SCST. Although the great majority of cases of gonadoblastoma occur in an individual with a disorder of sex development and an abnormal karyotype, a substantial number arise in a normal woman or girl with no evidence of a disorder of sex development. In the latter circumstance, it is important to distinguish gonadoblastoma from ovarian MGC-SCST. It is very likely that those gonadoblastomas arising in a normal individual develop through a different molecular pathway than the ones that occur in the dysgenetic gonads of an individual with a disorder of sex development.

Gonadoblastoma: origin and outcome.

Classical gonadoblastoma occurs almost entirely in the dysgenetic gonads of an individual who has a disorder of sex development; however, a small number of cases arise in individuals with a normal peripheral karyotype and no evidence of a disorder of sex development. Those gonadoblastomas that occur in an individual who has a Y chromosome or part thereof express testis specific protein Y-encoded 1 (TSPY1). If a gonad in those individuals contains germ cells with delayed maturation and also harbors the TSPY1 gene, the cells can undergo transformation to classical gonadoblastoma. The latter consists of rounded islands composed of germ cells, sex cord elements, and hyaline basement membrane material surrounded by a variably cellular stroma that sometimes contains steroid cells. Classical gonadoblastoma can be interpreted as a noninvasive or an in situ neoplasm that is the precursor of germinoma in some individuals and, indirectly, of other more aggressive germ cell neoplasms. The "dissecting" variant is derived from classical gonadoblastoma and is characterized by unusual growth patterns. Undifferentiated gonadal tissue is the precursor of gonadoblastoma; however, if all germ cells in an individual with undifferentiated gonadal tissue involute, the result is a secondary streak gonad. Undifferentiated gonadal tissue is a non-neoplastic condition resembling a streak gonad but additionally contains germ cells with delayed maturation that express octamer-binding transcription factor 4; however, other germ cells, show normal maturation and express TSPY1.

Whole-Genome and Segmental Homozygosity Confirm Errors in Meiosis as Etiology of Struma Ovarii.

Strumae ovarii are neoplasms composed of normal-appearing thyroid tissue that occur within the ovary and rarely spread to extraovarian sites. A unique case of struma ovarii with widespread dissemination detected 48 years after removal of a pelvic dermoid provided the opportunity to reexamine the molecular nature of this form of neoplasm. One tumor, from the heart, consisting of benign thyroid tissue was found to have whole-genome homozygosity. Another tumor from the right mandible composed of malignant-appearing thyroid tissue showed whole-genome homozygosity and a deletion of 7p, presumably the second hit that transformed it into a cancerous tumor. Specimens from 2 other cases of extraovarian struma confined to the abdomen and 8 of 9 cases of intraovarian struma showed genome-wide segmental homozygosity. These findings confirm errors in meiosis as the origin of struma ovarii. The histological and molecular findings further demonstrate that even when outside the ovary, strumae ovarii can behave nonaggressively until they receive a second hit, thereafter behaving like cancer.

Classic and "Dissecting" Gonadoblastoma in a Phenotypic Girl With a 46, XX Peripheral Karyotype and No Evidence of a Disorder of Sex Development.

Herein, we report a case of a 9-yr-old girl who had a 46, XX peripheral karyotype and apparent developmentally normal ovaries. She presented with abdominal pain and a right adnexal mass. No clinical or pathologic evidence of gonadal dysgenesis or undifferentiated gonadal tissue was detected. She underwent right salpingo-oophorectomy with rupture of the tumor at the time of operation due to recent adnexal torsion. The original pathologic diagnosis was gonadoblastoma and mixed germ cell tumor. Most significantly in our study, we identified a rare and novel pathway for the development of malignant mixed germ cell tumor from gonadoblastoma in the absence of identifiable dysgerminoma. The histologically identifiable steps of progression in our case were as follows: (1) residual islands of classic gonadoblastoma, (2) overgrowth by "dissecting" gonadoblastoma composed of transformed germ cells with clear cytoplasm and sex cord elements surrounded by a basement membrane, (3) stromal infiltration by dedifferentiated germ cells with loss of basement membrane, (4) formation of malignant mixed germ cell tumor. The dedifferentiated areas were composed of anaplastic germ cells with amphophilic cytoplasm that gradually replaced the sex cord elements by clonal expansion. Both the original transformed and the anaplastic germ cell components strongly expressed OCT4. We believe that the mixed germ cell tumor arose from the dedifferentiated germ cell component through neoplastic progression. This premise suggests that the germ cell component of "dissecting" gonadoblastoma rarely undergoes anaplastic change in the absence of transition to germinoma and can be the direct precursor of mixed germ cell tumor.

Protein expression of the transcription factors DMRT1, TCLF5, and OCT4 in selected germ cell neoplasms of the testis.

In the present study, we investigated protein expression of the transcription factors mammalian doublesex and mab-3 related transcription factor 1 (DMRT1), basic helix-loop-helix transcription factor-like 5 (TCLF5), and octamer-binding transcription factor 4 (OCT4) in normal human spermatogenesis, testicular mixed germ cell-sex cord stromal tumor (MGC-SCST), spermatocytic tumor, and seminoma. In normal human spermatogenesis, DMRT1 is expressed in the nuclei of spermatogonia but not in those of more mature germ cells. By way of contrast, TCLF5 is expressed in the nuclei of some clusters of primary spermatocytes that have entered meiosis 1, in secondary spermatocytes, and in round (early) spermatids in the seminiferous tubules of adults during the reproductive years. OCT4 is expressed in primordial germ cells but not in the seminiferous tubules of the normal adult testis during the reproductive years. DMRT1 is expressed in the germ cells of both testicular MGC-SCST and spermatocytic tumor, whereas TCLF5 is not expressed in either neoplasm. These low-grade neoplasms, however, differ histologically in that all the germ cell nuclei of testicular MGC-SCST resemble spermatogonia, whereas in spermatocytic tumor, the nuclei of the medium-sized and large cells resemble those of primary spermatocytes. Both neoplasms lack expression of OCT4. By way of contrast, in seminoma, a fully malignant testicular germ cell tumor, the germ cell nuclei express OCT4 but do not express either DMRT1 or TCLF5.

Classical gonadoblastoma: its relationship to the 'dissecting' variant and undifferentiated gonadal tissue.

Classical gonadoblastoma occurs almost entirely in the dysgenetic gonads of an individual who has a disorder of sex development. Approximately 40% of such neoplasms are bilateral. Almost all gonadoblastomas occur in patients who have a Y chromosome or part thereof; testis-specific protein Y-encoded 1 (TSPY1) is the putative gene. If a gonad in a patient who has a disorder of sex development contains germ cells with delayed maturation, and also harbours the TSPY1 gene, the cells can undergo transformation to classical gonadoblastoma. The latter consists of rounded islands composed of germ cells, sex cord elements and hyaline basement membrane material surrounded by a variably cellular gonadal stroma that sometimes contains steroid cells. Classical gonadoblastoma can be interpreted as a non-invasive neoplasm that is the precursor of germinoma and, indirectly, other more aggressive germ cell neoplasms. Undifferentiated gonadal tissue is the precursor of classical gonadoblastoma and contains germ cells with delayed maturation that express octamer-binding transcription factor 4 (OCT4); however, other germ cells show normal maturation and express TSPY1. If all germ cells in a patient with undifferentiated gonadal tissue involute, the result is a secondary streak. Undifferentiated gonadal tissue is a non-neoplastic condition that should be distinguished clearly from 'dissecting gonadoblastoma', a neoplasm derived from classical gonadoblastoma that is the precursor of some germinomas. 'Dissecting gonadoblastoma' is a variant of classical gonadoblastoma that has unusual growth patterns and contains both sex cord and germ cell elements. Clonal expansion of germ cells is a characteristic of the late stage of 'dissecting gonadoblastoma'.

Perspectives on testicular sex cord-stromal tumors and those composed of both germ cells and sex cord-stromal derivatives with a comparison to corresponding ovarian neoplasms.

Sex cord-stromal tumors (SCSTs) are the second most frequent category of testicular neoplasms, accounting for approximately 2% to 5% of cases. Both genetic and epigenetic factors account for the differences in frequency and histologic composition between testicular and ovarian SCSTs. For example, large cell calcifying Sertoli cell tumor and intratubular large cell hyalinizing Sertoli cell neoplasia occur in the testis but have not been described in the ovary. In this article, we discuss recently described diagnostic entities as well as inconsistencies in nomenclature used in the recent World Health Organization classifications of SCSTs in the testis and ovary. We also thoroughly review the topic of neoplasms composed of both germ cells and sex cord derivatives with an emphasis on controversial aspects. These include "dissecting gonadoblastoma" and testicular mixed germ cell-sex cord stromal tumor (MGC-SCST). The former is a recently described variant of gonadoblastoma that sometimes is an immediate precursor of germinoma in the dysgenetic gonads of patients with a disorder of sex development. Although the relationship of dissecting gonadoblastoma to the previously described undifferentiated gonadal tissue is complex and not entirely resolved, we believe that it is preferable to continue to use the term undifferentiated gonadal tissue for those cases that are not neoplastic and are considered to be the precursor of classical gonadoblastoma. Although the existence of testicular MGC-SCST has been challenged, the most recent evidence supports its existence; however, testicular MGC-SCST differs significantly from ovarian examples due to both genetic and epigenetic factors.

On the histogenesis of mixed germ cell-sex cord stromal tumour of the gonads.

AIMS: The origin of testicular mixed germ cell-sex cord stromal tumour (MGC-SCST) is uncertain, and the nature of this neoplasm is controversial. It has not been established whether the germ cells in testicular MGC-SCST are neoplastic or whether they are merely entrapped within an unclassified sex cord stromal tumour or related testicular neoplasm. In this investigation, we present additional evidence regarding the nature of the germ cells in testicular MGC-SCST. METHODS: We obtained 25 cases of MGC-SCST, 13 of which involved the testis and 12 occurred in the ovary for histological examination. Although the majority of the cases studied were archival, materials were available for immunocytochemical examination in 10 instances. RESULTS: We found that 10 of 13 testicular MGC-SCSTs studied had a sex cord component resembling unclassified sex cord stromal tumour. In two MGC-SCSTs that had prominent entrapped tubules, an intratubular component was identified. A total of 12 ovarian MGC-SCSTs were examined, and these neoplasms were more diverse in their histological appearance than the testicular examples. The germ cells often resembled those of dysgerminoma. Formation of imperfect follicular-like structures was a frequent feature in ovarian cases. CONCLUSIONS: In this investigation, we provide further evidence that the germ cells in testicular MGC-SCSTs are neoplastic; however, in the great majority of tumours, these cells are low-grade. Some testicular MGC-SCSTs arise from an intratubular component. We believe that the majority of ovarian and some testicular MGC-SCSTs arise more directly from simultaneous transformation of germ cells and sex cord derivatives.

Perspectives on testicular germ cell neoplasms.

Our knowledge of testicular germ cell neoplasms has progressed in the last few decades due to the description of germ cell neoplasia in situ (GCNIS) and a variety of specific forms of intratubular germ cell neoplasia, the discovery of isochromosome 12p and its importance in the development of invasiveness in germ cell tumors (GCTs), the identification of specific transcription factors for GCTs, and the recognition that a teratomatous component in mixed GCT represents terminal differentiation. Isochromosome 12p and 12p overrepresentation, collectively referred to as 12p amplification, are fundamental abnormalities that account for many types of malignant GCTs of the testis. Embryonal carcinoma is common in the testis but rare in the ovary, whereas the converse is true for mature cystic teratoma. Spermatocytic tumor occurs only in the testis; it has not been described in the ovary or extragonadal sites. The origin of ovarian mature cystic teratoma is similar to that of prepubertal-type testicular teratoma and dermoid cyst at any age in that it arises from a nontransformed germ cell, whereas postpubertal-type testicular teratoma arises from a malignant germ cell, most commonly through the intermediary of GCNIS. Somatic neoplasms, often referred to as monodermal teratomas, arise not infrequently from mature cystic teratoma of the ovary, whereas such neoplasms are rare in testicular teratoma with the exception of carcinoid. Integration of classical morphologic observations and emerging novel molecular studies will result in better understanding of the pathogenesis of GCTs and will optimize patient therapy.

Evidence of a dual histogenetic pathway of sacrococcygeal teratomas.

AIMS: Sacrococcygeal teratomas are rare tumours that occur most frequently in neonates, although adult cases also occur. The molecular pathogenesis of these tumours and their long-term prognosis is uncertain. We investigated the i(12p) status of a large number of primary sacrococcygeal teratomas in both children and adults, including cases with malignant germ cell tumour elements. METHODS AND RESULTS: Fifty-four sacrococcygeal teratoma specimens from 52 patients were identified, and available follow-up information was obtained. Fluorescence in-situ hybridization analysis was performed to identify isochromosome 12p [i(12p)] abnormalities on paraffin blocks of the tumours. Among the 48 paediatric patients, there were 44 teratomas and four tumours with combined teratoma and yolk sac tumour (one of whom also had primitive neuroectodermal tumour). The teratomas included 37 mature teratomas and 11 immature teratomas (four grade 1, two grade 2, and five grade 3). The 44 teratomas lacking a yolk sac tumour component were all negative for i(12p). The four tumours with a yolk sac tumour component were all positive for i(12p). The four adult cases all lacked non-teratomatous germ cell tumour components, immature elements, and i(12p). Follow-up information was available for 32 patients. Two patients with teratoma had recurrence, but were alive with no evidence of disease after long-term follow-up. One patient with combined teratoma and yolk sac tumour had recurrence 7 months after resection. The other patients were alive with no evidence of disease at last follow-up. CONCLUSIONS: Our data suggest that paediatric sacrococcygeal teratomas should be considered as two distinct groups with divergent histogenetic pathways. The prognosis of these tumours is excellent, despite rare recurrence.