A comparative morphological and immunohistochemical study of testicular seminomas and intracranial germinomas

A series of 10 classical testicular seminomas and 10 intracranial germinomas were reviewed and examined using immunohistochemical techniques. In particular, the staining profiles of the tumour cells and the nature of the mononuclear cell infiltrate at the two sites were studied and compared. The tumour cells in eight of the 10 intracranial germinomas and nine of the 10 seminomas exhibited positive staining with placental alkaline phosphatase. Only one intracranial germinoma showed evidence of human chorionic gonadotrophin expression. Tumour cells in all cases at both sites were negative for cytokeratin and vimentin. The lymphocytic infiltrate in both the testicular and intracranial tumours was similar, comprising T-cells and B-cells, the former predominantly. The presence of macrophages and granulomas in tumours at both sites was noted. These findings confirm the high degree of similarity of germinomas of intracranial and testicular origin, and support the hypothesis of a common derivation. We could find no evidence of differentiation of tumour cells at either site.     

Intermediate filaments and desmosomal plaque proteins in testicular seminomas and non-seminomatous germ cell tumours as revealed by immunohistochemistry

Summary Seminomas and non-seminomatous testicular germ cell tumours were studied for the presence of cytokeratin and vimentin filaments and desmosomes using immunohistochemical methods. In the majority of the classical seminomas and in seminomatous areas of mixed tumours most tumour cells appeared to lack cytokeratin filaments. Some seminomas contained a focally variable proportion of cells exhibiting cytokeratin-positive structures while other cases contained only few seminoma cells with a well developed fibrillar cytokeratin network. Gel electrophoresis of cytoskeletal proteins from microdissected regions revealed cytokeratin polypeptides nos. 8 and 18 typical of simple epithelia. In one seminoma, however, all, or almost all, tumour cells contained cytokeratin filaments. This finding is in line with the assumption of transitional forms between seminoma and embryonal carcinoma. Despite the lack - or variable expression - of cytokeratin filaments most seminoma cells contained desmosomes, although often few in number and irregularly distributed at the circumference of the cells. Loosely arranged and often very sparse vimentin fibrils were found in many, but not all seminoma cells. Double label immunofluorescence microscopy suggested that the majority of desmosomes was associated with intermediate filaments of the vimentin type. In contrast, in carcinoma cells of malignant teratomas, in well differentiated epithelial cells of intermediate-type malignant teratomas and in trophoblastic cells present in trophoblastic-type malignant teratomas cytokeratin filament bundles as well as desmosomes were decorated. The arrangement and density of the cytokeratin filament skeleton and of desmosomes varied with degree of maturation of the tissue. The most regular distribution and intensive staining of cytokeratin filaments and desmoplakin was found in mature tissues. Vimentin was demonstrated in mesenchymal areas and stroma cells. The results show that seminomas are distinguished from most other germ cell and non-germ cell tumours by the presence of true desmosomes together with scanty vimentin filaments in most tumour cells. In addition, they indicate that seminoma cells can be heterogenous in their cytoskeletal complement and may include cells with cytokeratin expression, indicative of a multi-potential character of the initially transformed cell(s).Supported in part by Fonds Zur Förderung der wissenschaftlichen Forschung (grant No. 4708 to H.D) and by the Deutsche Forschungsgemeinschaft (grants Mo 345/3 and Fr 308-17)     

Cytokeratin and CD30 expression in dysgerminoma

Dysgerminoma is a malignant germ cell tumor of the ovary that shares morphological, immunophenotypic, and genetic features with its testicular counterpart, seminoma. Recent evidence supports the hypothesis that seminoma can differentiate into non-seminomatous germ cell tumor types. The progression of these tumors can be measured by their acquisition of the potential to express cytokeratin intermediate filaments, a characteristic specific to epithelial differentiation. Although testicular seminomas have been widely investigated, little is known about cytokeratin or E-cadherin expression in dysgerminomas. We investigated 26 formalin-fixed, paraffin-embedded ovarian dysgerminomas with immunohistochemical stains for CAM5.2, AE1/AE3, epithelial membrane antigen, cytokeratin 7, cytokeratin 20, high-molecular-weight keratin, and E-cadherin. In addition, we investigated the CD30 and vimentin immunoreactivity of these tumors. Immunoreactivity for CAM5.2 and for AE1/AE3 was present in more than 10% of neoplastic cells in 5 (19.2%) of 26 cases and in 2 (7.7%) of 26 cases, respectively. Cytokeratin 7 showed only focal positivity and never showed positive staining in greater than 10% of dysgerminoma cells. E-cadherin staining was positive in 2 cases showing weak membranous immunostaining in more than 10% of cells. Vimentin immunoreactivity was observed in only 2 dysgerminomas, both of which had less than 10% of the neoplastic cells staining. Cytokeratin 20, epithelial membrane antigen, high-molecular-weight keratin, and CD30 were consistently negative in all cases. Our study demonstrates that cytokeratin expression in dysgerminomas is not unusual and is consistent with the hypothesis that dysgerminomas have the capacity to differentiate along epithelial lines. Furthermore, the immunohistochemical staining patterns for cytokeratins, E-cadherin, and CD30 in dysgerminomas need to be considered when assessing differential diagnoses in difficult cases of primary ovarian tumors.     

Importance of immunohistochemistry for neuro-oncology. IV. Distribution model of beta human chorionic gonadotropins in intracranial germ cell tumors

beta-Human choriogonadotropic hormone (beta-HCG) is considered a good marker for trophoblastic differentiation of germ cell tumors. 34 primary intracranial germ cell tumors (15 germinomas, 6 mature teratomas, 1 embryonal carcinoma, 2 endodermal sinus tumors and 10 mixed germ cell tumors) were immunohistochemically evaluated for the presence of beta-HCG positive cells. In 8 of 15 germinomas and 6 of 10 mixed germ cell tumors beta-HCG cells were demonstrable. In the germinomas such cells included both syncytiotrophoblastic and mononuclear cells which histologically did not correspond to the cytotrophoblast. In one case the patient had exhibited a precocious puberty. Of the 6 beta-HCG positive mixed germ cell tumors, two contained elements of choriocarcinoma. In the cytotrophoblasts of the choriocarcinoma regions, beta-HCG was only sparsely demonstrable. Both of these patients had manifest precocious puberty clinically. The advantage of immunohistochemical demonstration of the beta-HCG compared to conventional histology is in the definite identification of trophoblastic differentiation, in particular the exact recognition of the choriocarcinoma segments, which can be critical for the prognosis. Demonstration of isolated syncytiotrophoblasts and beta-HCG positive mononuclear cells in the seminomas is of no prognostic significance and is primarily of theoretical interest.     

Antibodies to cytokeratin and vimentin in testicular tumour diagnosis

Summary Thirteen primary and metastatic testicular germ cell tumours, including classical and anaplastic seminomas, and non-seminomatous testicular tumours were examined for their intermediate filament protein (IFP) types. The seminomas were shown to react with a monoclonal and a polyclonal antibody to bovine lens vimentin, while non-seminomatous germ cell tumours were strongly positive for a polyclonal and a monoclonal antibody to cytokeratin.In one case of seminoma with elevated serum levels ofHCG andFP, cytokeratin positive tumour cells were found. In the case of teratocarcinoma, several components of the tumour could be distinguished using a combination of antisera in double-label immunofluorescence microscopy. The glandular component of this tumour was positive with the polyclonal antikeratin, but also with the monoclonal cytokeratin antibody specific for glandular epithelia (RGE 53). However, the squamous component was negative with this latter antibody. Strikingly, the spindle cell component showed focal positivity for vimentin, with coexpression of cytokeratin and vimentin in some cells.Our data show that antibodies to cytokeratin and vimentin can be helpful in the diagnosis of testicular germ cell tumours, especially in the differentiation between seminomas and non-seminomatous tumours.This study was supported by a grant from the Dutch Cancer Foundation, The Queen Wilhelmina Fund (KWF), project NUKC 1981-12     

Synchronous primary mediastinal seminoma in a patient with colorectal adenocarcinoma

Primary mediastinal germ cell tumours are a rare primary tumour of the mediastinum. They share the same immunomorphological features to their gonadal counterparts but carry a worse prognosis. Primary mediastinal seminomas are exclusively found in male patients. Their diagnosis requires exclusion of primary gonadal 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.     

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.     

RNA-binding protein LIN28 is a sensitive marker of ovarian primitive germ cell tumours

Xue D, Peng Y, Wang F, Allan R W & Cao D
(2011) Histopathology 59 , 452–459 RNA‐binding protein LIN28 is a sensitive marker of ovarian primitive germ cell tumours Aims: LIN28 is an RNA‐binding protein that has been detected in testicular germ cell tumours (GCTs), but its status in ovarian GCTs is unknown. The aim was to determine the immunohistochemical profile of LIN28 in ovarian GCTs. Methods and results: Immunohistochemistry of LIN28 was performed in 110 primary and 11 metastatic ovarian GCTs. The percentage of tumour cells stained was scored as 0, 1+ (1–30% cells), 2+ (31–60%), 3+ (61–90%), and 4+ (>90%). To determine its specificity, we stained LIN28 in 119 non‐GCTs, including 37 clear cell carcinomas. Strong 4+ LIN28 staining was seen in 4/4 (100%) gonadoblastomas, 7/7 (100%) embryonal carcinomas (ECs), and 41/41 (100%) yolk sac tumours (YSTs). Among 39 dysgerminomas, 4+ staining was seen in 37 and 3+ staining in two (strong in 37; mixed weak and strong in two). Twelve of 14 immature teratomas showed variable LIN28 staining (1+ to 4+) in the immature neuroepithelium (weak to strong staining), whereas mature teratomas, carcinoids, struma ovarii and strumal carcinoids were negative. Only 5/117 non‐GCTs (1/37 clear cell carcinomas) showed weak to moderate 1–2+ staining. Conclusions: LIN28 is a sensitive marker for gonadoblastomas, dysgerminomas, ECs, and YSTs. LIN28 can be used to distinguish them from non‐GCTs.     

Endokrine Tumoren des Hodens

The most characteristic endocrine tumours of the testis are germ cell tumours and sex cord/gonadal stromal tumours. They include the primary carcinoid, the relation of which to teratomas is still unclear. In general, gonadal stromal tumours are rare, however, endocrine activity occurs in at least 10%-20%. Among gonadal stromal tumours, only Leydig cell tumours and Sertoli cell tumours are of practical importance. Endocrine disorders are mostly related to Leydig cell tumours (gynaecomastia, pubertas praecox). Although less frequent than the other gonadal stromal tumours, they can, in principle, occur. The large cell calcifying Sertoli cell tumour occurs in association with other complex disorders (i.e. Peutz-Jeghers syndrome). Valuable markers are: inhibin, calretinin, cytokeratin, melan-A, CD-99, Ki-67, androgen receptor and p53. As the conventional morphology and immunohistological markers frequently overlap, unclear cases should be referred to specialised centres.     

Parvovirus B19 is associated with benign testes as well as testicular germ cell tumours.

AIMS: Parvovirus B19 has been demonstrated in testes of patients with germ cell tumours but not in controls, raising the possibility that the virus has an aetiological role in these tumours. The aims of this study were to investigate the association of the virus with germ cell tumours and to localise the virus histologically. METHODS: DNA was extracted from paraffin wax embedded sections of testes from 10 seminomas, eight teratomas, two mixed seminoma/teratomas, and 10 testes showing benign histology. Polymerase chain reaction (PCR) amplification of three regions within the NS and VP1/2 genes was carried out in duplicate on all samples. One PCR positive case (seminoma/teratoma) was examined by microdissection of histologically defined tissue components followed by PCR amplification of parvoviral sequences. Samples from PCR positive patients were immunostained using a B19 specific monoclonal antibody. RESULTS: Seven cases were PCR positive, these comprised two of 10 seminomas, one of two mixed tumours, none of eight teratomas, and four of 10 benign controls. PCR analysis of the material microdissected from the seminoma/teratoma showed the presence of the virus in regions of seminoma, teratoma, intratubular germ cell neoplasia, normal tubules, and connective tissue. All patient samples studied immunohistochemically were negative. CONCLUSIONS: This confirms the presence of parvovirus B19 in a proportion of germ cell tumours; however, in one patient, the virus was widespread in the tissue components and not confined to tumour cells. In addition, the virus was present in control benign testes. These data suggest that B19 might not be of aetiological importance in germ cell tumours of testis.     

Parvovirus B19 is associated with benign testes as well as testicular germ cell tumours.

AIMS: Parvovirus B19 has been demonstrated in testes of patients with germ cell tumours but not in controls, raising the possibility that the virus has an aetiological role in these tumours. The aims of this study were to investigate the association of the virus with germ cell tumours and to localise the virus histologically. METHODS: DNA was extracted from paraffin wax embedded sections of testes from 10 seminomas, eight teratomas, two mixed seminoma/teratomas, and 10 testes showing benign histology. Polymerase chain reaction (PCR) amplification of three regions within the NS and VP1/2 genes was carried out in duplicate on all samples. One PCR positive case (seminoma/teratoma) was examined by microdissection of histologically defined tissue components followed by PCR amplification of parvoviral sequences. Samples from PCR positive patients were immunostained using a B19 specific monoclonal antibody. RESULTS: Seven cases were PCR positive, these comprised two of 10 seminomas, one of two mixed tumours, none of eight teratomas, and four of 10 benign controls. PCR analysis of the material microdissected from the seminoma/teratoma showed the presence of the virus in regions of seminoma, teratoma, intratubular germ cell neoplasia, normal tubules, and connective tissue. All patient samples studied immunohistochemically were negative. CONCLUSIONS: This confirms the presence of parvovirus B19 in a proportion of germ cell tumours; however, in one patient, the virus was widespread in the tissue components and not confined to tumour cells. In addition, the virus was present in control benign testes. These data suggest that B19 might not be of aetiological importance in germ cell tumours of testis.     

Intranuclear membranous profiles in germinoma cells--a variant of nuclear pockets and intranuclear annulate lamellae

When ultrastructurally examining 24 germinomas comprising 12 seminomas, 4 dysgerminomas, 1 mediastinal germinoma, and 7 intracranial germinomas, intranuclear membranous profiles were noticed in 17 germinomas, ranging from 20-100 nm in width and 3 microns in length. With occasional connections to the nuclear envelope through a small hole, intranuclear membranous profiles in germinoma cells were considered as clefts of the nuclear envelope. While most frequently situated under the inner nuclear membrane, they varied in configuration as well as distribution. As sequestered round mass of nuclear material, they were a variant of nuclear pockets containing nucleoplasm. Intranuclear annulate lamellae were occasionally present apart from the nuclear envelope and connected with nuclear clefts. Eleven of the twelve seminomas and 6 of the twelve non-seminomatous germinomas showed intranuclear membranous profiles, and the incidence of such profiles was much higher in seminomas than in non-seminomatous germinomas. Intranuclear membranous profiles facing the inner nuclear membrane were also noted in spermatogonia in adolescents and adults. It was suggested that intranuclear membranous profiles in germinoma cells could be structures following ones occasionally seen in spermatogonia.     

Gonadoblastoma with contralateral dysgerminoma in a young female--a case report

Gonadoblastomas are rare germ cell and sex cord stromal tumours, often associated with dysgerminomas. They occur almost entirely in patients with pure or mixed gonadal dysgenesis and in male pseudohermaphroditism. A 19 year old female was admitted in our hospital for evaluation of primary amenorrhoea. She had poor secondary sexual characters, left sided streak gonad and right sided ovarian tumour. Histopathology showed gonadoblastoma in streak gonad with contralateral dysgerminoma. This case is presented because of its rarity and clinical importance of recognizing such cases because of excellent prognosis.     

INTRANUCLEAR MEMBRANOUS PROFILES IN GERMINOMA CELLS——A VARIANT OF NUCLEAR POCKETS and INTRANUCLEAR ANNULATE LAMELLAE

When ultrastructurally examining 24 germinomas comprising 12 seminomas, 4 dysgerminomas, 1 mediastinal germinoma, and 7 intracranial germinomas, intranuclear membranous profiles were noticed in 17 germinomas, ranging from 20-100 nm in width and 3^m in length. With occasional connections to the nuclear envelope through a small hole, intranuclear membranous profiles in germinoma cells were considered as clefts of the nuclear envelope. While most frequently situated under the inner nuclear membrane, they varied in configuration as well as distribution. As sequestered round mass of nuclear material, they were a variant of nuclear pockets containing nucleoplasm. Intranuclear annulate lamellae were occasionally present apart from the nuclear envelope and connected with nuclear clefts. Eleven of the twelve seminomas and 6 of the twelve non-seminomatous germinomas showed intranuclear membranous profiles, and the incidence of such profiles was much higher in seminomas than in non-seminomatous germinomas. Intranuclear membranous profiles facing the inner nuclear membrane were also noted in spermatogonia in adolescents and adults. It was suggested that intranuclear membranous profiles in germinoma cells could be structures following ones occasionally seen in spermatogonia. ACTA PATHOL. JPN. 35: 605–619, 1985.     

Ovarian mucinous tumour arising in mature cystic teratoma and associated with pseudomyxoma peritonei: report of two cases and comparison with ovarian involvement by low-grade appendiceal mucinous tumour

AIMS: It is currently accepted that primary ovarian tumours rarely, if ever, give rise to mucinous ascites/pseudomyxoma peritonei (PMP) which most commonly results from the intra-abdominal spread of an appendiceal mucinous neoplasm. However, primary ovarian mucinous tumours of appendiceal type arising within mature cystic teratomas appear to represent an exception to this rule. In this report two further examples of this rare tumour are described, and the immunohistological phenotype including expression of MUC proteins is compared with secondary ovarian involvement by low-grade appendiceal mucinous neoplasm. METHODS: Two cases of ovarian mucinous tumour associated with mature cystic teratoma and PMP are described. The tumours were examined immunohistochemically for expression of cytokeratin (CK)7, CK20, carcinoembryonic antigen (CEA), CDX-2, MUC2, MUC5AC and MUC6. The results were compared with four cases of ovarian neoplasia secondary to primary appendiceal low-grade mucinous tumour. RESULTS: The ovarian mucinous tumours associated with mature cystic teratomas were morphologically similar to those secondary to appendiceal neoplasia. They comprised irregularly distributed glands and cysts lined by tall, mucin-rich epithelial cells exhibiting focal villoglandular architecture and low grade cytological atypia. The immunophenotype of the teratoma-associated tumours and those secondary to appendiceal neoplasia was identical: there was strong and diffuse expression of CK20, CEA, CDX-2, MUC2 and MUC5AC with no reactivity for the other antisera tested. CONCLUSIONS: PMP associated with primary ovarian neoplasia is rare, and probably restricted to mucinous tumours arising in mature cystic teratomas. The immunohistological findings in this study further support the view that such tumours exhibit a lower gastrointestinal and, more specifically, appendiceal phenotype. Careful examination and sampling of the ovaries may be required to demonstrate the teratomatous component of these tumours.     

Epithelial–mesenchymal transition markers in malignant ovarian germ cell tumors

The purpose of this study was to determine the expression and potential clinical role of epithelial‐to‐mesenchymal transition (EMT)‐related factors in malignant ovarian germ cell tumors (MOGCT). Protein expression of E‐cadherin, N‐cadherin, P‐cadherin, Zeb1, HMGA2, and vimentin by immunohistochemistry was analyzed in 42 MOGCT from patients treated in Norway during the period 1981–2001. Expression was analyzed for association with clinicopathologic parameters. E‐cadherin (p = 0.016) and HMGA2 (p = 0.002) expression was significantly higher in immature teratomas and yolk sac tumors compared with dysgerminomas. Vimentin (p < 0.001) and Zeb1 (p = 0.029) staining was significantly higher in immature teratomas compared with yolk sac tumors and dysgerminomas, whereas no significant differences were observed for N‐cadherin and P‐cadherin. EMT‐associated markers were not significantly related to clinicopathologic parameters including age, tumor diameter, and FIGO stage. In conclusion, based on this limited series, EMT‐associated markers are not associated with clinical parameters in MOGCT, in contrast to ovarian carcinoma. EMT‐related proteins are differentially expressed among various MOGCT subtypes, suggesting differences in biological characteristics associated with invasion and metastasis.     

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.