Trisomy 12 in benign fibroma and granulosa cell tumor of the ovary

Extrauterine Mesonephric-like Neoplasms: Expanding the Morphologic Spectrum

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms arising in the uterine corpus and ovary which have been added to the recent 2020 World Health Organization Classification of Female Genital Tumors. They have similar morphology and immunophenotype and exhibit molecular aberrations similar to cervical mesonephric adenocarcinomas. It is debated as to whether they are of mesonephric or Mullerian origin. We describe the clinical, pathologic, immunohistochemical, and molecular features of 5 cases of extrauterine mesonephric-like proliferations (4 ovary, 1 extraovarian), all with novel and hitherto unreported features. These include an origin of MLA in extraovarian endometriosis, an association of ovarian MLA with high-grade serous carcinoma, mixed germ cell tumor and mature teratoma, and a borderline ovarian endometrioid tumor exhibiting mesonephric differentiation. Four of the cases exhibited a KRAS variant and 3 also a PIK3CA variant. In reporting these cases, we expand on the published tumor types associated with MLA and report for the first time a borderline tumor exhibiting mesonephric differentiation. We show the value of molecular testing in helping to confirm a mesonephric-like lesion and in determining the relationship between the different neoplastic components. We provide further evidence for a Mullerian origin, rather than a true mesonephric origin, in some of these cases. We also speculate that in the 2 cases associated with germ cell neoplasms, the MLA arose out of the germ cell tumor.

Molecular comparison of pure ovarian fibroma with serous benign ovarian tumours

OBJECTIVE

Ovarian fibromas and adenofibromas are rare ovarian tumours. They are benign tumours composed of spindle-like stromal cells (pure fibroma) or a mixture of fibroblast and epithelial components (adenofibroma). We have previously shown that 40% of benign serous ovarian tumours are likely primary fibromas due to the neoplastic alterations being restricted to the stromal compartment of these tumours. We further explore this finding by comparing benign serous tumours to pure fibromas.

RESULTS

Performing copy number aberration (CNA) analysis on the stromal component of 45 benign serous tumours and 8 pure fibromas, we have again shown that trisomy of chromosome 12 is the most common aberration in ovarian fibromas. CNAs were more frequent in the pure fibromas than the benign serous tumours (88% vs 33%), however pure fibromas more frequently harboured more than one CNA event compared with benign serous tumours. As these extra CNA events observed in the pure fibromas were unique to this subset our data indicates a unique tumour evolution. Gene expression analysis on the two cohorts was unable to show gene expression changes that differed based on tumour subtype. Exome analysis did not reveal any recurrently mutated genes.

Numerical Chromosome Aberrations in Fibrothecoma

Cytogenetic analysis on a 7-day-old culture of a fibrothecoma showed only numerical chromosome abnormalities: 57, XX, +4, +5, +6, +10, + 12, +12, +14, +17, +18, +19, +20. The finding of an extra copy of chromosome 12 in mesenchymal tumors, mostly benign and originating from the female genital tract, may possibly point towards their common embryonic origin.

Copy number aberrations in benign serous ovarian tumors: a case for reclassification?

PURPOSE

Serous ovarian carcinomas are the predominant epithelial ovarian cancer subtype and it has been widely believed that some or all of these may arise from precursors derived from the ovarian surface epithelium or fimbriae, although direct molecular evidence for this is limited. This study aimed to conduct copy number (CN) analysis using a series of benign and borderline serous ovarian tumors to identify underlying genomic changes that may be indicative of early events in tumorigenesis.

EXPERIMENTAL DESIGN

High resolution CN analysis was conducted on DNA from the epithelial and fibroblast components of a cohort of benign (N = 39) and borderline (N = 24) serous tumors using the Affymetrix OncoScan assay and SNP6.0 arrays.

RESULTS

CN aberrations were detected in the epithelium of only 2.9% (1 of 35) of serous cystadenomas and cystadenofibromas. In contrast, CN aberrations were detected in the epithelium of 67% (16 of 24) of the serous borderline tumors (SBT). Unexpectedly, CN aberrations were detected in the fibroblasts of 33% (13 of 39) of the benign serous tumors and in 15% (3 of 20) of the SBTs. Of the 16 cases with CN aberrations in the fibroblasts, 12 of these carried a gain of chromosome 12.

CONCLUSIONS

Chromosome 12 trisomy has been previously identified in pure fibromas, supporting the concept that a significant proportion of benign serous tumors are in fact primary fibromas with an associated cystic mass. This is the first high resolution genomic analysis of benign serous ovarian tumors and has shown not only that the majority of benign serous tumors have no genetic evidence of epithelial neoplasia but that a significant proportion may be more accurately classified as primary fibromas.

Imbalances of chromosomes 4, 9, and 12 are recurrent in the thecoma-fibroma group of ovarian stromal tumors

Traditional cytogenetic studies of ovarian stromal tumors are few, although trisomy 12 has been frequently documented with fluorescence in situ hybridization (FISH). In the current study, karyotypic analysis of four ovarian stromal tumors and a review of the literature suggest that numerical abnormalities of chromosomes 4 and 9 might also be important, possibly as secondary changes. To determine the frequency of 4, 9, and 12 aneuploidy in a larger group of ovarian tumors, FISH studies were performed on eight fibromas, three thecomas, one fibrothecoma, and five cellular fibromas. Trisomy 12 was identified in all five cellular fibromas as well as in two fibromas and the fibrothecoma. Gain of chromosome 9 was confined to the cellular fibromas. Loss of chromosomes 4 and/or 9 was prominent in the fibromas. These findings confirm the presence of trisomy 12 as a nonrandom chromosomal abnormality in ovarian stromal tumors. Moreover, these conventional and molecular cytogenetic data indicate that gain of chromosome 9 in addition to gain of chromosome 12 is prominent in cellular fibroma. In contrast, loss of chromosomes 4 and/or 9 are recurrent in fibroma. In summary, imbalances of chromosomes 4 and 9 appear to represent important secondary abnormalities in the thecoma-fibroma ovarian tumor group.

Comparative genome hybridization reveals specific genomic imbalances during the genesis from benign through borderline to malignant ovarian tumors

Ovarian cancer is one of the most common types of malignancy in women throughout the developed world. Despite recent therapeutic advances, long-term survival is poor because ovarian cancer is largely asymptomatic in its early stages. Comparative genomic hybridization (CGH) was applied to a series of 8 benign, 8 borderline, and 17 malignant ovarian to establish genomic imbalances associated with tumor progression. Benign and borderline tumors were characterized by losses at 1p32 approximately p11, 2q14 approximately q34, 4q13 approximately q34, 5q11 approximately q23, and 6q12 approximately q24, as well as gains of 6p and chromosome 12. Similar chromosomal changes were also detected in malignant tumors but included additional chromosomal changes: gains at 1q21 approximately q31, 2p, 3q, 5p, 7, 10p, 12p, 16p, 17, 19q, 20q, and 22q, as well as losses at X, 3p, 8p, 9, 11p, 13, 14, and 18. Some individual cases of benign and borderline tumors revealed no genetic alterations detectable by CGH, suggesting that these tumors may represent a subset of tumors that originate by an alternative mechanism of tumorigenesis. Furthermore, our findings reveal that borderline tumors are more similar to benign tumors than to malignant tumors with respect to their genetic profiles.

Molecular cytogenetics of ovarian granulosa cell tumors by comparative genomic hybridization

OBJECTIVE

Patients with stage I granulosa cell tumors (GCTs) may occasionally develop metastasis, which is hard to predict using pathologic criteria. It is interesting to elucidate whether certain chromosomal imbalances (CIs), detected by comparative genomic hybridization (CGH), could be useful prognostic markers.

METHODS

CGH was used to identify CI(s) in 37 adult-type GCTs from 36 women. Nonrandom CIs were compared with clinical and pathological features to evaluate their significance as a prognostic marker.

RESULTS

Twenty-two (61%) of the 36 primary tumors had CIs. One woman's tumor showed identical CIs to another tumor that occurred in contralateral ovary 2 years later, supporting a metastatic nature. The nonrandom CIs included losses of 22q (31%), 1p33-p36 (6%), 16p13.1 (6%), and 16q (6%) and gains of 14 (25%), 12 (14%), and 7p15-p21 (6%). No tumor exhibited high-level amplification. The associations between each CI and pathological features, including the growth pattern, tumor size, and mitotic activity, were not evident. The only CI repeatedly detected in tumors with metastasis was monosomy 22, which presented in 2 of the 4 cases with metastasis but also in 2 of the 5 cases without recurrence for more than 5 years.

CONCLUSIONS

Monosomy 22 was the most common CI in GCTs, which often coexisted with trisomy 14 (in 55% cases). Deletion of 22q seems to be, albeit not very specific, associated with the risk of early metastases of stage I disease. The role of loss-of-function mutation(s) of certain putative tumor suppressor gene(s) on 22q is worthy of further investigations.

Trisomy 8 as sole karyotypic aberration in an ovarian metastasizing Sertoli-Leydig cell tumor

Sertoli-Leydig cell tumors (SLCTs) represent a rare group of sex-cord stromal tumors of the ovary of unknown pathogenesis. We report a SLCT of intermediate differentiation with peritoneal recurrence and lymph node metastasis 12 months after removal, including cytogenetic analysis by comparative genomic hybridization and fluorescence in situ hybridization, which showed trisomy 8 as sole unbalanced karyotypic aberration. Our results provide evidence that a simple numeric chromosomal abnormality in SLCT may be associated with a malignant phenotype and suggest that the molecular pathogenesis of SLCT may be different from ovarian granulosa-stromal cell tumors.

Tetrasomy 12 in ovarian tumors of thecoma-fibroma group: A fluorescence in situ hybridization analysis using paraffin sections

Recent cytogenetical studies have indicated that trisomy 12 is a feature of ovarian tumors in the thecoma-fibroma group. Ten cases of these ovarian tumors were studied in total, including two thecomas, two fibrothecomas, four fibromas, one cellular fibroma and one fibrosarcoma, to clarify the relationship between polysomy 12 and proliferative activity in these tumors. Each formalin-fixed, paraffin-embedded tumor tissue was examined by fluorescence in situ hybridization to determine copy numbers of chromosome 12 and by immunohistochemical staining of Ki-67 for evaluation of tumor cell proliferation. Gains of trisomy 12 were found in seven of the 10 cases, and the percentage of cells with tetrasomy 12, but not that of cells with trisomy 12, was significantly and positively correlated with percentage of Ki-67-positive cells, but significantly and inversely correlated with patient age. These findings suggest that tetrasomy 12 is an age-related aberration of chromosome 12 in ovarian tumors of the thecoma-fibroma group, and that such tumors exhibit more active proliferation in younger patients.

Trisomy of chromosome 10 in two cases of ovarian carcinoma

Simple numerical chromosome aberrations have been observed in tumorigenesis and may point to indicative initiating or early events in tumorigenesis. We have identified two cases of ovarian carcinomas with trisomy of chromosome 10 using conventional GTG-banding and fluorescence in situ hybridization. This is, to our knowledge, the first report of trisomy 10 as a simple karyotypic abnormality observed in ovarian carcinoma. These results suggest that further studies investigating whether chromosome 10 genes are associated with the pathogenesis of some ovarian tumors are warranted.

Loss of the Y-chromosome in the primary metastasis of a male sex cord stromal tumor: pathogenetic implications

The first published chromosomal pattern of the retroperitoneal lymph node metastasis of a malignant gonadal stroma cell tumor of the adult testis is presented. Karyotyping showed structural chromosomal abnormalities and loss of the Y-chromosome. This loss was confirmed in primary tumor and metastasis using fluorescence in situ hybridization (FISH). The characteristic chromosomal abnormality of adult testicular germ cell tumors, an i(12p), was not present. The results are compared with other data of testicular and ovarian sex cord stromal tumors. From the comparison of the male tumors, it is concluded that loss of the Y-chromosome might have a pathogenetic significance.

Monosomy 22 and trisomy 14 may be early events in the tumorigenesis of adult granulosa cell tumor

The finding of monosomy 22 and trisomy 14 in a case of adult type of granulosa-thecoma cell tumor and the available information from the literature allow for the hypothesis that, especially monosomy 22, but also trisomy 14, may be early events in the tumorigenesis of adult sex cord-stromal tumors in general, and of granulosa-thecoma cell tumors in particular.

Monosomy 22 in a fibrothecoma

We found a 45,XX, -22 karyotype as the sole chromosome change in a fibrothecoma of a 67-year-old woman. These cytogenetic findings are discussed in the light of relevant cytogenetic and pathology literature data on ovarian sex cord tumors.

Fibrosarcoma versus cellular fibroma of the ovary: a comparative study of their proliferative activity and chromosome aberrations using MIB-1 immunostaining, DNA flow cytometry, and fluorescence in situ hybridization

We retrospectively analyzed the proliferative activity and the centromeric copy number of chromosomes 8, 12, and 17 in three cases of fibrosarcoma and eight cases of cellular fibroma of the ovary using MIB-1 immunostaining, DNA flow cytometry, and fluorescence in situ hybridization (FISH) on paraffin-embedded tissue specimens. In our study, both the MIB-1 labeling index (LI) and the proliferative index (% of cells in S + G2 + M phase) in fibrosarcomas were higher than those in cellular fibromas. The FISH analysis demonstrated the sole abnormality of a gain of trisomy 12 cells in all eight cases of cellular fibroma. Both a gain of trisomy 12 cells and a gain of tetrasomy 12 cells were observed in one case of fibrosarcoma. A gain of trisomy 8 cells was observed in all two fibrosarcomas in which signals were detected. By contrast, neither a gain of trisomy 8 cells nor a gain of tetrasomy 12 cells was observed in any of the eight cases of cellular fibroma. Chromosome 17 showed disomy in all eleven cases. On the basis of these findings, a gain of trisomy 8 cells is therefore considered to be an adequately effective marker to distinguish between cellular fibroma and fibrosarcoma of the ovary, and it may also be related to the proliferative activity of fibrosarcoma of the ovary.

Comparative cytogenetic studies of benign, borderline, and malignant epithelial ovarian tumors

Comparative cytogenetic studies were performed in 40 cases of untreated epithelial ovarian tumors. Of these 40 tumors, 13 were classified as benign, 3 as borderline, and 24 as malignant, according to the WHO classification for ovarian tumors. Of 13 benign ovarian tumors, 4 (30.8%) showed chromosomal abnormalities. Of 4 ovarian tumors, 3 (75%) had single chromosomal abnormalities, and the remaining tumor (25%) retained multiple chromosomal abnormalities. Of 3 borderline-malignant ovarian tumors, 2 (66.7%) showed chromosomal abnormalities. Of 2 ovarian tumors, 1 (50%) indicated single chromosomal abnormalities, and the remaining tumor (50%) revealed multiple chromosomal abnormalities. Of 24 malignant ovarian tumors, 20 (83.3%) showed chromosomal abnormalities. Of these 20 ovarian tumors, 3 (15%) had single chromosomal abnormalities, and the other 17 (85%) exhibited multiple chromosomal abnormalities. These data indicate that the rate of chromosomal abnormalities, especially multiple abnormalities, increases following the progression of malignancy in epithelial ovarian tumors.

Karyotypic characteristics of borderline malignant tumors of the ovary: trisomy 12, trisomy 7, and r(1) as nonrandom features

Clonal karyotypic abnormalities were detected in five of 14 cytogenetically analyzed borderline malignant ovarian tumors of clinical stages I-II. One mucinous and one seropapillary tumor had trisomy 7 and r(1)(p36q42) as the sole chromosome abnormality, respectively. Trisomy 12 was found in the remaining three cases. It was the only change in one mucinous and one serous tumor, whereas the third, a seropapillary borderline tumor, had the karyotype 49,XX,+5,+8, +12. These findings, especially when collated with those of previous reports on ovarian borderline tumor cytogenetics, indicate that +12 is the most consistent chromosomal aberration in this group of neoplasms and that also +7 and r(1) are nonrandom features. From the karyotypic point of view, benign ovarian tumors and well-differentiated carcinomas are similar to borderline ovarian tumors, with the possible exception that the former have no tendency to form r(1). Highly malignant carcinomas, on the other hand, are typically much more complex. Chromosome-level changes therefore cannot account for the putative phenotypic passage through the most innocuous tumor stages as epithelial ovarian neoplasms go from benign to fully malignant.

Monosomy 22 in two ovarian granulosa cell tumors

Cytogenetic studies of ovarian sex cord stromal cell tumors, although limited in number, have found trisomy 12 to be a recurring abnormality, especially in fibromas and granulosa cell tumors (GCTs). However, recent fluorescence in situ hybridization (FISH) studies have failed to confirm a high prevalence of trisomy 12 in GCTs. We describe the karyotypic findings in one adult and one juvenile GCT. Only the juvenile GCT had an extra, abnormal chromosome 12, but both the adult and juvenile GCT had monosomy 22. In light of these findings and the data in the literature, we suggest that monosomy 22 may be important in the genesis of these relatively rare tumors.

Infant cardiac fibroma with clonal t(1;9)(q32;q22) and review of benign fibrous tissue cytogenetics

Cardiac fibromas are rare lesions which occur more frequently in infants and children than in the adult population. These tumors are nonmalignant proliferations of connective tissue most often found in the left ventricular myocardium or septal myocardium. No cytogenetic studies of cardiac fibromas have been reported. We report a case of an infant with a subepicardial tumor in whom the cytogenetic analysis showed a clonal reciprocal translocation, 46,XY,t(1;9)(q32;q22),inv(9)(p11q12)c. We review the literature regarding cardiac fibromas and briefly discuss the cytogenetics of benign fibrous neoplasias.

Nonrandom chromosome breakpoints at Xq26 and 2q33 characterize cemento-ossifying fibromas of the orbit

BACKGROUND

Cytogenetic reports of histologically benign fibroosseous lesions are rare, with only nine previously reported cases. None of these previous studies revealed consistent numerical or structural chromosome aberrations, and to the authors' knowledge, no karyotypic abnormalities in cemento-ossifying fibromas of the orbit have been reported.

METHODS

Short term in situ culture and Giesma-band chromosome methods were used to analyze three cementifying fibromas of the orbit: one from a 13-year-old African American male, one from a 14-year-old Hispanic male, and one from a 17-year-old white male.

RESULTS

Cytogenetic findings in these three cases revealed the presence of identical chromosomal breakpoints occurring in all three tumors at bands Xq26 and 2q33. Two of the tumors showed an identical t(X;2)(q26;q33) reciprocal translocation as the sole abnormality. The third tumor revealed an interstitial insertion of bands 2q24.2q33 into Xq26 as the sole abnormality.

CONCLUSIONS

The authors described new nonrandom breakpoints in fibroosseous lesions of the orbit, which can result from at least two different types of structural chromosomal aberrations. The identification of recurring breakpoints at Xq26 and 2q33 provides a new cytogenetic tumor marker for the identification of this tumor subtype. The sublocalization of breakpoints in this tumor should provide important information for the precise localization and characterization of genes involved in the histiogenesis of these lesions.

Numerical and structural chromosome abnormalities in an ovarian fibrothecoma

Cytogenetic analysis of a fibrothecoma of ovary revealed numerical and structural chromosome abnormalities, i.e., 44,XX, dup(1)(p13p31),del(3)(p14) add (10p), -16, -22. This is the first report of numerical and structural abnormalities in a fibrothecoma of the ovary.

Cytogenetic changes in ovarian mucinous cystadenocarcinoma of low malignant potential with persistent pseudomyxoma peritonei

Minimal cytogenetic data are available for low malignant potential ovarian neoplasms, and none for those complicated by pseudomyxoma peritonei. Cytogenetic analysis was performed on tissue obtained from a patient undergoing repeat evacuation of mucin and mucin-producing implants in pseudomyxoma peritonei originating from an ovarian mucinous cystadenocarcinoma of low malignant potential. Specimens obtained from intraperitoneal implants during one of the cyto/mucin-reductive procedures revealed a mixture of normal female karyotype (46,XX) and an abnormal karyotype with a deletion involving the short arm of chromosome 1, and a balanced translocation involving chromosomes 2 and 6, [46,XXdel(1)(p21p31), t(2;6)(q35;p21)]. The vast majority of the cells from three subsequent cyto/mucin-reductive procedures displayed a normal female karyotype with few cells containing random abnormalities.

Cytogenetic studies of epithelial ovarian carcinoma

We performed cytogenetic studies of 36 human epithelial ovarian carcinomas using in situ culture and robotic harvest. We obtained analyzable metaphases of all 36 tumors (100%). One or more chromosomally abnormal clones were observed in 80% of tumors. Common clonal chromosome gains (each occurring in six or more cases) included +1, +2, +3, +6, +7, +9, and +12. Common clonal chromosome losses (occurring in 12 or more cases) included -X, -4, -8, -11, -13, -15, -17, and -22. Common clonal structural abnormalities (occurring in four or more cases) involved regions 1p36, 1q32, 1q42, 3p13-->p26, 3q26-->q29, 7p22, 9q34, 11p13-p15, 17q21-->q23, 19p13.3, and 19q13.3. Trisomy 12 was noted as the sole anomaly in three of five borderline and grade 1 tumors. Two grade 2 tumors contained i(1q), -14, -15 and -22. The results suggest that the pathogenesis of borderline and low-grade tumors may differ from that of higher grade tumors. Two high-grade tumors had an apparent translocation between 17q21 and 19p13.3, two chromosome regions believed to be critical to ovarian carcinogenesis.

Trisomy 14 in two cases of granulosa cell tumor of the ovary

Cytogenetic analysis of granulosa cell tumor of the ovary was performed in two patients. G-banding analysis of cells cultured 3-5 days showed that the karyotype of each tumor contained normal diploid cells as well as cells with identical aberration: trisomy 14. This is the first report of trisomy 14 in two cases of granulosa cell tumor of the ovary. Flow cytometric DNA content analysis was also performed.

Translocation (6;16) in a case of granulosa cell tumor of the ovary

We performed a cytogenetic study of an ovarian granulosa cell tumor (GCT). Tumor cells showed a translocation (6;16); the full karyotype was 45,XX-6,dic(6;16)(q11;q22)/44,XX,-6,-22,dic(6;16)(q11;q22),-22/46,XX,- 6,dic(6;16)(q11;q22), +dic(6;16)(q11;q22). This is the second case of GCT with structural changes of chromosome 6 leading to loss of 6q material.

Trisomy 12 and 4 in a thecoma of the ovary

Cytogenetic analysis of short-term tissue culture from a thecoma of the ovary demonstrated the presence of trisomies of chromosomes 12 and 4 in all analyzed cells. Our finding confirms the consistency with which trisomy 12 is observed in benign sex cord/stromal tumors and suggests that trisomy 4 may be a second event in tumorigenesis of thecoma.

Trisomy 12 and K-ras-2 amplification in human ovarian tumors

Cytogenetic analysis was performed on 11 benign and borderline ovarian tumors. Trisomy 12, identified as a sole abnormality in 6 tumors, is likely a specific karyotypic change in different benign and borderline tumors and may well be a primary chromosomal lesion in these tumors. The possible association between amplification of the proto-oncogene K-ras-2 which is located on chromosome 12 and trisomy 12 was investigated. DNA blotting analysis of 64 tumors indicates that trisomy 12 does not seem to be related to K-ras-2 amplification in ovarian tumors. K-ras-2 amplification was observed in 3 high-grade tumors from 3 patients with metastases.