Chromosomal rearrangements in chondromatous tumors

Chondroma of the urinary bladder: A case report

RATIONALE

Chondromas are benign tumors comprising cartilaginous tissue that commonly occur in the small bones of the hands and feet. Chondromas are extremely rare in extraskeletal soft tissues, and only six cases of bladder chondromas have been reported thus far.

PATIENT CONCERNS

A 75-year-old woman presented with abdominal pain and urinary symptoms, including increased frequency and a weak stream.

DIAGNOSIS

Cystoscopy revealed a well-defined bladder mass over the anterior bladder wall. The pathology report showed neoplastic chondrocytes within the hyalinized and focal myxoid matrix, and immunopositivity for S-100, leading to the seventh known diagnosis of bladder chondroma.

INTERVENTIONS

The tumor was endoscopically resected. The postoperative stay was uneventful, and 5 days later, the patient was discharged after the removal of the urinary catheter.

OUTCOMES

One month after surgery, repeated cystoscopy showed no recurrence of the bladder tumor, and the patient reported improvement in urinary symptoms and relief of lower abdominal pain.

LESSONS

Chondromas of the urinary bladder can present as urinary symptoms and abdominal pain in older patients. Transurethral resection is the treatment of choice.

Chondroma of the Bladder: An Atypical Localization

Chondroma is a benign tumour of mesenchymal origin that is composed of cartilage and rarely located in soft tissues, being described so far only in four cases, as located in the bladder, according to our knowledge. We describe the fifth case of a 67-year-old woman who consulted for microscopic haematuria, with an endoscopic finding of submucosal nodular image in the anterior wall of the bladder, which after resection and the histologic study shows cartilage and fibroconnective tissue, in part hyalinised, and positive immunohistochemical staining of cells with vimentin and S-100; this fact can support the diagnosis of bladder chondroma.

Dedifferentiated Chondrosarcoma

We describe the clinicopathologic and cytogenetic findings of an unusual dedifferentiated chondrosarcoma with a rhabdomyosarcomatous component in a case report and review the relevance of these findings with respect to seven previously reported cases. Cytogenetic studies of dedifferentiated chondrosarcoma are limited to 2 previously described cases, both with dedifferentiated components distinct from this case. In this study, cytogenetic analysis of 3 separate specimens, biopsy with chondrosarcoma, definitive surgical, and lung metastasis with rhabdomyosarcomatous component, revealed clonal karyotypic aberrations in each. A structural abnormality involving the short arm of chromosome 17 and extra copies of chromosomes 5, 7, 12, and 20 were common to all three specimens. These findings reveal multiple shared chromosomal anomalies between the primary chondrosarcoma and the dedifferentiated components, which suggests a clonal evolution. Int J Surg Pathol 2(4):319-328, 1995

Mesenchymal Chondrosarcoma: Clinicopathologic Study of 20 Cases

Context.—Mesenchymal chondrosarcoma is a rare, high-grade malignancy of bone or soft tissue with a unique, biphasic histology and poor prognosis. Because of its rarity and variable length of disease-free survival, the natural history of the disease remains poorly understood.

Objective.—To present clinical, radiographic, and histopathologic features of mesenchymal chondrosarcoma from one of the largest case series collected by a single, senior-level bone pathologist.

Design.—Twenty cases were reviewed in consultations spanning 45 years.

Results.—Eighteen tumors (90%) originated in bone, and 2 tumors (10%) were of extraskeletal origin. Of the skeletal tumors, locations included craniofacial bones (n  =  9; 50%), ribs and chest wall (n  =  4; 22%), sacrum and spinal elements (n  =  3; 17%), and lower extremities (n  =  2; 11%), whereas soft tissue tumors were located about the scapula (n  =  1; 50%) and lower extremity (n  =  1; 50%). Plain radiographs demonstrated calcified, osteolytic lesions with extraosseous extension. Typical histologic features were identified consisting of small, round or spindled cells, interspersed with hyaline cartilage islands. Seventeen patients (85%) were treated surgically, and 8 patients (40%) received adjuvant treatment. Seven patients (35%) were living at last follow-up, 1.8 to 12.5 years after diagnosis, and 8 patients (40%) died between 1.2 and 21.8 years after diagnosis.

Conclusions.—Mesenchymal chondrosarcoma presents multiple challenges. Diagnostic pitfalls include inadequate biopsy samples, which may result in sample error. Sox9 has been proposed as a unique marker for mesenchymal chondrosarcoma which may improve diagnostic specificity. Treatment and prognosis vary considerably. Patients who receive surgery and chemotherapy seem to fare better. Multicenter studies with higher sample numbers may improve our understanding of this malignancy.

Pathobiology of selected tumors of the base of the skull

Skull base surgery is a new subspeciality, and, up to this point, most articles on this subject have focused on innovative operative-reconstructive approaches to tumors in this region. It is now important that we embark on a new era, the era of tumor biology, and concentrate on new ways of evaluating these neoplasms from a pathologic viewpoint. The hematoxylin-cosin section is no longer an end point, but just a beginning. This is the age of molecular biology. It is important that these tumors be evaluated, either prospectively or retrospectively, employing immunohistochemical staining, flow cytometry, oncogene expression, cytogenetics, or other techniques in order to identify important prognostic features. Data from these additional studies may then be used to develop new treatment strategies. Skull base societies should develop protocols for one or more of these tumors to ensure that they are indeed evaluated uniformly. In this article I emphasize the importance of accurate histologic classification or subclassification of these neoplasms and focus on contemporary parameters that may or may not impact on prognosis.

Cytogenetic findings in 14 benign cartilaginous neoplasms

Benign cartilaginous tumors represent a spectrum of neoplastic processes with variable clinical and pathologic presentations. These tumors are histologically characterized by the presence of chondrocytes surrounded by a cartilaginous matrix. Few studies describe karyotypic abnormalities in these benign lesions. We report a series of 14 chondromas from a single institution. Conventional cytogenetics was performed on short term cultures from all cases. Clonal chromosome aberrations were found in nine tumors. One soft tissue chondroma contained three clones with t(6;12)(q12;p11.2), t(3;7)(q13;p12), and der(2)t(2;18)(p11.2;q11.2). Three periosteal chondromas displayed random structural aberrations of chromosomes 2, 3, 6, 7, and 11 and loss of chromosome 13. Among the enchondromas, three tumors displayed chromosome losses, one contained a complex translocation involving chromosomes 12, 15, and 21 as well as an inv(2)(p21q31),t(12;15;21)(q13;q14;q22) and a separate enchondroma showed a translocation involving chromosomes 12 and 22. Our data suggest that considerable cytogenetic heterogeneity exists among benign chondromatous tumors.

Genomic profiling of chondrosarcoma: chromosomal patterns in central and peripheral tumors

PURPOSE

Histologic grade is currently the best predictor of clinical course in chondrosarcoma patients. Grading suffers, however, from extensive interobserver variability and new objective markers are needed. Hence, we have investigated DNA copy numbers in chondrosarcomas with the purpose of identifying markers useful for prognosis and subclassification.

EXPERIMENTAL DESIGN

The overall pattern of genomic imbalances was assessed in a series of 67 chondrosarcomas using array comparative genomic hybridization. Statistical analyses were applied to evaluate the significance of alterations detected in subgroups based on clinical data, morphology, grade, tumor size, and karyotypic features. Also, the global gene expression profiles were obtained in a subset of the tumors.

RESULTS

Genomic imbalances, in most tumors affecting large regions of the genome, were found in 90% of the cases. Several apparently distinctive aberrations affecting conventional central and peripheral tumors, respectively, were identified. Although rare, recurrent amplifications were found at 8q24.21-q24.22 and 11q22.1-q22.3, and homozygous deletions of loci previously implicated in chondrosarcoma development affected the CDKN2A, EXT1, and EXT2 genes. The chromosomal imbalances in two distinct groups of predominantly near-haploid and near-triploid tumors, respectively, support the notion that polyploidization of an initially hyperhaploid/hypodiploid cell population is a common mechanism of chondrosarcoma progression. Increasing patient age as well as tumor grade were associated with adverse outcome, but no copy number imbalance affected metastasis development or tumor-associated death.

CONCLUSION

Despite similarities in the overall genomic patterns, the present findings suggest that some regions are specifically altered in conventional central and peripheral tumors, respectively.

Tumor-biology and current treatment of skull-base chordomas

Chordomas are rare, slow growing tumors of the axial skeleton, which derive from the remnants of the fetal notochord. They can be encountered anywhere along the axial skeleton, most commonly in the sacral area, skull base and less commonly in the spine. Chordomas have a benign histopathology but exhibit malignant clinical behavior with invasive, destructive and metastatic potential. Genetic and molecular pathology studies on oncogenesis of chordomas are very limited and there is little known on mechanisms governing the disease. Chordomas most commonly present with headaches and diplopia and can be readily diagnosed by current neuroradiological methods. There are 3 pathological subtypes of chordomas: classic, chondroid and dedifferentiated chordomas. Differential diagnosis from chondrosarcomas by radiology or pathology may at times be difficult. Skull base chordomas are very challenging to treat. Clinically there are at least two subsets of chordoma patients with distinct behaviors: some with a benign course and another group with an aggressive and rapidly progressive disease. There is no standard treatment for chordomas. Surgical resection and high dose radiation treatment are the mainstays of current treatment. Nevertheless, a significant percentage of skull base chordomas recur despite treatment. The outcome is dictated primarily by the intrinsic biology of the tumor and treatment seems only to have a secondary impact. To date we only have a limited understanding this biology; however better understanding is likely to improve treatment outcome. Hereby we present a review of the current knowledge and experience on the tumor biology, diagnosis and treatment of chordomas.

Assessment of the clinical and molecular impact of different cytogenetic subgroups in a series of 272 lipomas with abnormal karyotype

Conventional lipomas harbor karyotypic changes that could be subdivided into four, usually mutually exclusive, categories: rearrangement, in particular through translocations, of chromosome bands 12q13-15, resulting in deregulation of the HMGA2 gene, loss of material from or rearrangement of chromosome 13, supernumerary ring or giant marker chromosomes, and aberrations of chromosome band 6p21. In the present study, 272 conventional lipomas, two-thirds of them deep-seated, with acquired clonal chromosome changes were assessed with regard to karyotypic and clinical features. A nonrandom distribution of breakpoints and imbalances could be confirmed, with 83% of the cases harboring one or more of the previously known cytogenetic hallmarks. Correlation with clinical features revealed that lipomas with rings/giant markers were larger, occurred in older patients, were more often deep-seated, and seemed to have an increased tendency to recur locally, compared with tumors with other chromosome aberrations. The possible involvement of the HMGA2 gene in cases that did not show any of the characteristic cytogenetic changes was further evaluated by locus-specific metaphase fluorescence in situ hybridization (FISH) and RT-PCR, revealing infrequent cryptic disruption of the gene but abundant expression of full length or truncated transcripts. By FISH, we could also show that breakpoints in bands 10q22-23 do not affect the MYST4 gene, whereas breakpoints in 6p21 or 8q11-12 occasionally target the HMGA1 or PLAG1 genes, respectively, also in conventional lipomas.

Trisomy 8 as the sole cytogenetic abnormality in a case of extraskeletal mesenchymal chondrosarcoma

Mesenchymal chondrosarcoma is a rare malignant tumor that comprises about 3-10% of all sarcomas. Reports of cytogenetic studies of mesenchymal chondrosarcoma are limited and no consistent cytogenetic abnormality has surfaced. Some mesenchymal chondrosarcomas have a t(11;22) translocation suggesting a relationship with the PNET/Ewing tumor family. We report what to our knowledge is the first case of trisomy 8 as the sole cytogenetic abnormality in a mesenchymal chondrosarcoma.

Cytogenetic findings in benign cartilaginous neoplasms

Cytogenetic analysis has improved our understanding of the histopathogenesis of many benign and malignant bone and soft tissue tumors, as well as served as an important diagnostic adjunct for these pathologic entities. Cytogenetic reports of benign cartilaginous tumors, however, are relatively few. This is unfortunate, as distinguishing benign and malignant cartilaginous neoplasms can often be difficult. In this study, the cytogenetic findings of two enchondromas, two periosteal chondromas, and one soft part chondroma and a review of the literature are reported. Abnormal diploid or near-diploid clones were detected in all specimens analyzed. Although a tumor-specific anomaly did not emerge from these studies, involvement of certain chromosomes/chromosomal regions appears recurrent.

Translocation der(13;21)(q10;q10) in skeletal and extraskeletal mesenchymal chondrosarcoma

Cytogenetic studies of mesenchymal chondrosarcoma are few and to date, no specific or recurrent aberrations have been found. In this investigation, the cytogenetic and molecular cytogenetic (spectral karyotypic and fluorescence in situ hybridization) findings for two mesenchymal chondrosarcomas, one arising skeletally and the other extraskeletally, are reported. An identical Robertsonian translocation involving chromosomes 13 and 21 [der(13;21)(q10;q10)] was detected in both cases, possibly representing a characteristic rearrangement for this histopathologic entity. Both cases also exhibited loss of all or a portion of chromosomes 8 and 20 and gain of all or a portion of chromosome 12. The observation of similar chromosomal abnormalities in both skeletal and extraskeletal mesenchymal chondrosarcoma supports a genetic as well as histopathologic relationship between these anatomically distinct neoplasms.

PTEN mutation is rare in chondrosarcoma

Chondrosarcoma is the second most common primary malignant neoplasm of bone in adults, but the major genetic events involved in the progression of this often-fatal cancer remain to be elucidated. Loss of heterozygosity of chromosome 10q has been reported in 67% of chondrosarcoma. The tumor suppressor gene PTEN is located on chromosome 10q, specifically 10q23, raising the possibility that the loss of PTEN function is responsible for some chondrosarcomas. The authors examined 40 chondrosarcoma tumors and tumor-derived cell lines for alterations in PTEN. Only one mutation resulting in a truncated PTEN protein was detected, which was in a metastasized extraskeletal myxoid chondrosarcoma. Thus, mutated PTEN is an uncommon event in the development of chondrosarcoma. The high frequency of loss of heterozygosity on 10q suggests the presence of additional tumor suppressor genes at these loci.

Cytogenetic aberrations and their prognostic impact in chondrosarcoma

Chondrosarcoma is the second most common primary malignancy of bone. Cytogenetic data are available from close to 100 cases, including all subtypes of chondrosarcoma. Specific chromosomal rearrangements have been identified only in extraskeletal myxoid chondrosarcoma (EMC). Strong prognostic factors are largely missing, although size and, in particular, histologic tumor grade have been implicated. In the present study, we investigated the genomic aberrations in 59 chondrosarcomas (six grade 1, 24 grade 2, and 29 grade 3, including dedifferentiated tumors), excluding EMC, by chromosome banding analysis and DNA flow cytometry and correlated the findings with clinical outcome. Hyperhaploid to near-diploid karyotypes were found in half of the cases, and there was a good correlation between cytogenetics and flow cytometry data; discrepancies were seen primarily in cases with normal karyotypes and in those with -Y as the sole anomaly. Abnormal karyotypes, excluding those with -Y as the only change, were found in 36 cases. No recurrent structural aberration was found, but a nonrandom pattern of aberrations was seen. Total or partial gains and losses were the dominant karyotypic features. Genomic imbalances found in at least 10 cases included -1p36, -1p13-p22, -4, -5q13-q31, -6q22-qter, +7p13-pter, -9p22-pter, -10p, -10q24-qter, -11p13-pter, -11q25, +12q15-qter, -13q21-qter, -14q24-qter, -18p, -18q22-qter, +19, +20pter-q11, +21q, and -22q13. At the latest follow-up, 19 patients had experienced distant metastases, and the 5-year metastasis-free survival rate was 0.69. By univariate analysis, malignancy grade and loss of material from 6q, 10p, 11p or 11q, 13q, and 22q were associated with impaired metastasis-free survival. Only -13q was an independent prognostic factor for metastasis, regardless of tumor grade or size.

Correlation between clinicopathological features and karyotype in 100 cartilaginous and chordoid tumours. A report from the Chromosomes and Morphology (CHAMP) Collaborative Study Group

The evaluation of chondroid lesions requires full integration of clinical, radiographic, and pathological data; tumour typing is often a challenge for the diagnostic pathologist. Although a variety of chromosomal abnormalities have been documented in chondroid lesions, the potential usefulness of cytogenetic analysis remains unclear. This study has critically reviewed and analysed 117 karyotyped samples from 100 patients with cartilaginous and chordoid tumours. Cases were selected based on successful chromosomal analysis and adequacy of clinical, radiographic, and pathological information. To ensure objective evaluation, the cytogenetic results were correlated in a double-blind setting with consensus diagnoses independently determined on each case, after complete review of the histological, radiographic, and clinical findings. Karyotypic aberrations were identified in 41/92 cartilaginous tumours (5/11 osteochondromas, 2/3 chondromyxoid fibromas, 0/4 chondroblastomas, 11/29 chondromas, 0/3 chondroid tumours of undetermined malignant potential, 22/40 chondrosarcomas and 1/2 miscellaneous cartilaginous lesions) and 5/8 chordomas. Complex karyotypic changes were a feature of malignant tumours (chondrosarcoma and chordoma) and of chondrosarcoma among cartilaginous tumours, where they correlated with high tumour grade. Among primary well-differentiated cartilaginous lesions of bone, the finding of an abnormal karyotype was consistently associated with a grade 1 chondrosarcoma diagnosis. Among karyotypically abnormal cartilaginous tumours, loss of distal 8q was associated with osteochondroma, +5 with synovial chondroma/chondromatosis and parosteal or soft tissue chondroma, alterations of chromosome arm 6q with chondromyxoid fibroma, +7 with bone chondrosarcoma, and 17p1 alterations with grade 3 chondrosarcoma. Alterations involving 12q13 characterized synovial chondroma/chondromatosis in the chondroma group and myxoid chondrosarcoma of bone in the chondrosarcoma group. In conclusion, cytogenetic abnormalities in chondroid lesions are common and are not randomly distributed. They are associated with malignancy/tumour grade as well as with specific diagnoses in many cases, and can therefore be of potential value for tumour typing.

Novel translocation (9;12)(q22;q24) in secondary chondrosarcoma arising from hereditary multiple exostosis

We report a new translocation in a patient with a history of hereditary multiple exostosis (HME) who developed a recurrent grade I chondrosarcoma involving the sacrum and retroperitoneum. Karyotypic analysis of the tumor revealed a sole chromosome abnormality t(9;12)(q22;q24.3). To our knowledge, this translocation has not been previously identified in either chondrosarcoma, HME, or related tumor types. Our novel translocation may be related to the sarcomatous degeneration of the pre-existing exostosis.

Chromosome 9 alterations and trisomy 22 in central chondrosarcoma: a cytogenetic and DNA flow cytometric analysis of chondrosarcoma subtypes

Chondrosarcomas are malignant cartilaginous tumors. Most are located in the medullar cavity (central chondrosarcoma), and a minority develop in a preexisting osteochondroma (peripheral chondrosarcoma). The authors present karyotypes for 37 central, peripheral, juxtacortical, and dedifferentiated chondrosarcomas. Using loss of heterozygosity (LOH) analysis and DNA flow cytometry, the authors previously showed that central and peripheral chondrosarcomas probably evolve by different genetic mechanisms. Peripheral chondrosarcoma is characterized by genetic instability, as was previously shown by a high percentage of LOH and a broad range in DNA ploidy. The authors now show that all peripheral chondrosarcomas tested are aneuploid, combined with many nonspecific chromosomal aberrations. Two juxtacortical chondrosarcomas showed normal chromosome numbers combined with limited structural alterations, substantiating that juxtacortical and peripheral chondrosarcomas are two clinicopathologically different entities with a different genetic background. Central chondrosarcomas were previously found to be peridiploid with limited LOH, most frequent at 9p21. In the current study, chromosome 9 was involved in five of seven central chondrosarcomas compared with only one of four peripheral chondrosarcomas. Three central tumors showed involvement of the 9pl2-22 region, suggesting an important role for chromosome 9 in the oncogenesis of central chondrosarcoma. Moreover, trisomy 22 was found in four central chondrosarcomas only.

Chondroblastoma-like chondroma of soft tissue: an underrecognized variant and its differential diagnosis

Soft-tissue chondromas are usually composed entirely of mature hyaline cartilage. Infrequently, however, they may exhibit morphologic features that result in diagnostic difficulty. The authors report a series of eight hypercellular soft-tissue chondromas composed of enlarged chondrocytes within a variable amount of chondroid matrix that often demonstrated delicate calcifications and contained numerous osteoclast-like multinucleated giant cells. This histologic appearance closely resembles that of chondroblastoma of bone. However, its extraosseous location, dense cellularity, and poorly formed cartilage can cause confusion with more aggressive chondroid neoplasms of soft tissue. The clinicopathologic features of these chondroblastoma-like chondromas are discussed, emphasizing the characteristics that facilitate their accurate identification.

Prognostic factors and outcome of pelvic, sacral, and spinal chondrosarcomas: a center-based study of 69 cases

BACKGROUND

The surgical treatment of chondrosarcoma of the pelvis, sacrum, and spine is complex and technically demanding. As such, adequate surgical margins have been difficult to achieve, resulting in poor local control and survival. The objective of this study was to assess the outcome of patients with chondrosarcomas in these sites who were treated at a tumor center by using modern, aggressive surgical techniques and to identify prognostic factors.

METHODS

Sixty-nine consecutive patients with chondrosarcoma of the pelvis (46 cases), sacrum (11 cases), and mobile spine (12 cases) who were treated at Sahlgrenska University Hospital from 1967 to 1999 were included in this study. Demographic information and follow-up data were obtained and statistically analyzed.

RESULTS

There were 53 men and 16 women with a mean age of 45 years and a mean tumor size of 12 cm. There were 61 conventional chondrosarcomas, Grades 1-3 (with 13 arising in a preexisting osteochondroma) and 8 Grade 4 chondrosarcomas (7 dedifferentiated and one mesenchymal). The overall local recurrence rate was 27%, and the estimated overall 5- and 10-year survival rates were 72% and 67%, respectively. In contrast, the observed local recurrence rate was 3% (1 patient) in 31 patients whose conventional chondrosarcomas were resected with adequate surgical margins; 90% of these patients survived and most of them (26 of 31 or 84%) were continuously disease free. Significant factors associated with a worse prognosis with respect to local control and/or survival were high histologic tumor grade, increasing patient age, primary surgery outside of a tumor center, incisional biopsy versus a noninvasive diagnostic procedure, and inadequate surgical margins.

CONCLUSIONS

Center-based diagnosis and treatment using modern aggressive surgical techniques significantly improve the prognosis of patients with chondrosarcoma of the pelvis, sacrum, and spine.

Chromosomal changes in a dedifferentiated chondrosarcoma: a case report and review of the literature

The chromosome abnormalities observed in a dedifferentiated chondrosarcoma are reported. A new molecular cytogenetic technique, spectral karyotyping, was used to identify and confirm structural rearrangements in this case. A review of the literature revealed that nine cases have been reported, in eight of which a complete description of the cytogenetic abnormalities was described. Structural aberrations were most frequently reported in chromosomes 1 and 9, and chromosomes 7 and 19 were most frequently observed to be involved in numerical aberrations (trisomy and tetrasomy). In chondrosarcomas, structural aberrations in chromosomes 1 and 9 and trisomy or tetrasomy of chromosome 7 are among the more frequently observed aberrations.

Clonal chromosome abnormalities in enchondromas and chondrosarcomas

We report cytogenetic findings in short-term cell cultures from five enchondromas and four chondrosarcomas. Clonal chromosome aberrations were found in one case of enchondroma, and in all cases of chondrosarcoma. The only enchondroma with nonrandom abnormalities had a reciprocal t(8;17)(q23;p13), and monosomies 9, 19, and/or 22. In contrast to the few karyotypic findings in one of five enchondromas, the four chondrosarcomas were commonly characterized by cytogenetic heterogeneity, with a tendency for increasing karyotypic complexity in higher grade tumors. Two cases, one grade III and one metastasizing grade II chondrosarcoma, revealed hypodiploid stem- and sidelines with loss of chromosomes 6, 10, 13, 14, and 22, as common chromosomal abnormalities, suggesting a distinct karyotypic pattern in a subset of biologically aggressive chondrosarcomas.

Documentation of EWS gene rearrangements by fluorescence in-situ hybridization (FISH) in frozen sections of Ewing's sarcoma-peripheral primitive neuroectodermal tumor

Prompt and accurate diagnosis of small round cell tumors warrants ancillary studies. Recently, two-color fluorescence in-situ hybridization (FISH) using probes for specific gene rearrangements has gained wide acceptance. EWS gene rearrangements, present in essentially 100% of Ewing's Sarcoma/peripheral primitive neuroectodermal tumor, were evaluated by FISH on frozen sections (FS) of tumor biopsies from 10 patients, plus a negative control, and in seven other malignant neoplasms of childhood. 4mu FS were hybridized overnight, using a single EWS gene-specific probe spanning the EWS breakpoint. We identified EWS rearrangements in 8 of 10 cases (80%) of Ewing's Sarcoma/pPNET. There are no known false positives in diploid or near-diploid tumors, or in any of the non-EWS tumors tested; the uncommon false negative can be confirmed by RT-PCR. Hyperdiploid cases with multiple copies of chromosome 22 may be better evaluated by two-color FISH. This is the first use on FS biopsy material of a single probe for EWS, capable of detecting all known EWS rearrangements, in ES and other tumors. Utilization of this ancillary technique on FS for ES/pPNET and other tumors with distinctive chromosomal translocation is highly specific, reliable, expeditious (24-36 hours) and cost-effective.

Altered p53 is associated with aggressive behavior of chondrosarcoma: a long term follow-up study

BACKGROUND

p53 is a major tumor suppressor gene that has been implicated in the biology of a variety of human neoplasms, including some that affect the skeleton. Recent studies based on small numbers of cases have shown that overexpression or alteration of the p53 gene is frequently present in high grade, clinically aggressive chondrosarcomas of bone. In this study, the authors addressed the relation between overexpression and alteration of the p53 gene and the clinical aggressiveness of chondrosarcoma in a large series of patients for whom long term follow-up data were available.

METHODS

The authors analyzed the expression and/or alteration of the p53 gene in 158 cases of chondrosarcoma of bone using immunohistochemistry, single-strand conformation polymorphism, and direct sequencing. They then related the findings to various clinicopathologic parameters and long term follow-up data.

RESULTS

The presence of overexpression and/or structural alterations of the p53 gene was documented in 38.1% of chondrosarcomas of bone. A statistically significant correlation was observed between overexpression or alteration of the p53 gene and both the histologic grade of the tumor and the presence of metastasis. The probability of local recurrence free, metastasis free, and overall survival was significantly higher for patients with no overexpression or alteration of p53 than for patients with p53 overexpression or alteration.

CONCLUSIONS

Overexpression or alteration of the p53 gene is an important predictor of aggressive clinical behavior in chondrosarcoma of bone.

Deletion 1p in a low-grade chondrosarcoma in a patient with Ollier disease

Ollier disease is an uncommon, nonhereditary developmental disorder affecting enchondral ossification. Cytogenetic analysis of low-grade chondrosarcoma in a patient with Ollier disease (multiple enchondromatosis) revealed an interstitial deletion, del(1)(p11p31.2), as the only chromosome abnormality. This is the first cytogenetic study of a chondrosarcoma in a patient with Ollier disease. Such patients are at risk of developing chondrosarcoma and, because del(1p) is frequent in chondrosarcoma, it is suggested that this cytogenetic finding is associated with early chondrosarcomatous transformation.

Solitary enchondroma with clonal chromosomal abnormalities

We report a case of a solitary enchondroma located in the head of the left fibula in a 50-year-old patient and present the findings of histopathologic investigation and cytogenetic analysis. The tumor revealed simple karyotypic abnormalities with t(8;17)(q23;p13) and loss of chromosomes 9, 19, and 22 as clonal chromosomal changes. Only a few enchondromas with chromosome aberrations have been published previously; nevertheless, it appears that benign and malignant cartilaginous tumors may have similar chromosomal abnormalities.

Chromosomal abnormalities in low grade chondrosarcoma and a review of the literature

In this study, cytogenetic analysis of two low-grade chondrosarcomas revealed relatively simple chromosomal complements with structural rearrangements involving chromosomes 1, 6, and 12 [46,XY,add(16)(q24)[3]/46,XY,t(1;20)(q21;q11),t(6;17)(q23;q23)[3]/46,XY, t(4;14)(q12;q24),t(5;6)(q12;p21) [2] and 45,XY,t(12;16)(q13;q24),-14[17]/44,idem,add(4)(p16),-17,[2] respectively]. Previously published reports of chondrosarcoma have revealed structural abnormalities of chromosomes 1, 6, 9, 12, and 15 as common. Also, a correlation between the simplicity or complexity of the abnormalities seen and histologic grade has been suggested. The findings of the current study support these earlier observations.

Clonal chromosome aberrations with monosomy of chromosome 8 in a case of grade III chondrosarcoma

We report cytogenetic findings in a case of grade III chondrosarcoma. Complex clonal chromosome aberrations including monosomy of chromosomes 4, 8, 13, and a consistent t(5;14)(q23;p12) were observed in all cells. There were no structural or numerical anomalies involving chromosome 12. The complexity of the chromosome aberrations reflect the advanced stage of this chondrosarcoma; we suggest a possible involvement of the EXT1 gene located on chromosome 8.

Involvement of chromosomes 6 and 11 in a soft tissue chondroma

Cytogenetic analysis of a soft tissue chondroma revealed monosomy 6 and rearrangement of chromosome 11. Previously described 12q13-q15 involvement was not found. Aberrations of chromosomes 6 and 11, however, have been reported before in this type of benign cartilaginous tumor.

Musculoskeletal oncology--advances in cytogenetics and molecular genetics and their clinical implications

Although musculoskeletal malignancies comprise a small group of cancers, a vast number of histological subtypes have been identified attesting to the heterogeneity of this class of tumours and the growing interest in their development. The mode of management for both bone and soft tissue sarcomas has been examined extensively and treatment guidelines have been proposed. Despite the intensive study and multidisciplinary treatment, a substantial proportion of tumours remain recalcitrant to therapy and recur locally and systemically. Improved methods of characterising these tumours may help in understanding their biology. Cytogenetic and molecular genetic techniques allow a subcellular dissection of these malignancies which may aid the identification of mechanisms that are important in tumorigenesis. Already candidate genes have been isolated which may play an important role in the deregulation of proliferation and or the adoption of a malignant phenotype, features which are fundamental in tumour development. By studying the molecular biology and cytogenetics of tumours it may be possible to improve diagnostic and prognostic accuracy thereby minimising over and under treatment.

A fibroadenoma with a t(4;12) (q27;q15) affecting the HMGI-C gene, a member of the high mobility group protein gene family

An intracanalicular fibroadenoma of the breast showing a clonal chromosomal aberration t(4;12) (q27;q15) as the sole cytogenetic abnormality is described. In order to narrow down the breakpoint region on chromosome 12 on the molecular level we performed fluorescence in situ hybridization (FISH) analysis with a cosmid pool originating from a YAC-contig overspanning part of the region 12q14-15. We were able to narrow down the breakpoint to an approximately 230kb fragment belonging to the HMGI-C gene which maps within an area recently designated as MAR (Multiple Aberration Region). The chromosomal breakpoints of other frequent benign solid tumors, i.e. lipomas, uterine leiomyomas, and pleomorphic adenomas are clustered within the third intron of that gene.

Chromosome 9 related aberrations and deletions of the CDKN2 and MTS2 putative tumor suppressor genes in human chondrosarcomas

Deletions on the short arm of chromosome 9 (9p21 region) have been reported in a number of hematopoietic and solid tumors. These aberrations on 9p have been previously associated with the loss of the interferon gene cluster and the gene for methylthioadenosine phosphorylase (MTAP), localized to the 9p21-22 region. Recently, two putative tumor suppressor gene(s) CDKN2 and MTS2 have been mapped to the 9p21 region, and shown to be deleted in a large number of tumors including leukemias, melanomas, bladder cancers and brain tumors. We have previously reported a similar 9p21 abnormality and deletions of the CDKN2 and MTS2 genes in a myxoid chondrosarcoma cell line and its subclones. In this study we report consistent abnormalities of chromosome 9 in additional chondrosarcomas examined by a detailed cytogenetic and molecular analysis. Seven chondrosarcoma cell lines, one primary chondrosarcoma, and a benign chondroma were examined. Four of the seven tumor cell lines examined showed grossly visible aberrations of chromosome 9. Molecular analysis of these chondrosarcoma cell lines revealed hemizygous deletions of the interferon genes, and the absence of the MTAP gene, protein or activity. In addition, four of the seven chondrosarcoma cell lines also showed deletions of the CDKN2 and/or MTS2 putative tumor suppressor genes, or the absence of the CDKN2 protein product. No such chromosome 9 related aberrations were detected in the benign chondroma. These data suggest that chromosome 9p21 abnormality, and deletions of the CDKN2 and MTS2 tumor suppressor genes may be a significant event in the development of chondrosarcomas.

Partial deletions of the CDKN2 and MTS2 putative tumor suppressor genes in a myxoid chondrosarcoma

Cytogenetic abnormalities of chromosome 9 (9p21) have been reported in a large number of tumors that include malignant melanomas, gliomas, lung cancers and leukemias. These aberrations on 9p have been previously shown to involve the loss of the interferon gene cluster and the gene for methylthioadenosine phosphorylase (MTAP), both of which have been mapped to the 9p21 region. Recently, two putative tumor suppressor gene(s) CDKN2 and MTS2, have been mapped to the 9p21 region, and have been shown to be deleted in a large number of hematopoietic and solid malignancies. In this study we report a cytogenetic and a detailed molecular analysis of a myxoid chondrosarcoma cell line 105KC and its clonal derivatives 105AJ, 105AJ1.1, 105AJ3.1, and 105AJ5.1. Specifically, we have demonstrated chromosome 9p21 related abnormalities by cytogenetic analysis, the associated loss of the interferon gene cluster, and the loss of the immunoreactive MTAP protein and activity. In addition, we have also shown the presence of deletions involving the CDKN2 and the MTS2 putative tumor suppressor genes in these chondrosarcoma cell lines. The above studies were extended to other chondrosarcoma cell lines and primary tumors, where similar deletions of the CDKN2 and MTS2 genes were found to be present (unpublished data). This suggests a potential role for the involvement of the CDKN2 and MTS2 putative tumor suppressor genes in the development of chondrosarcomas.

Chromosome rearrangements in synovial chondromatous lesions

Short-term cultures from one synovial chondroma and three cases of synovial chondromatosis, a lesion for which no previous karyotypic information exists, were cytogenetically analysed. Whereas the chondroma displayed the relatively simple karyotype 46,XY,add(12)(q13),der(17)t(12;17)(q13;q21), more complex changes were found in the three cases of chondromatosis: case 1, 47,XY,der(1)inv(1)(p13q25)del (1)(q25q32), t(1;12)(q25;q13), + 5,der(12)add(12)(p11)t(1;12)(p22;q13); case 2, 47,XY,add(10)(q26), + 20/46 idem,-6/46,XY,t(2;4)(q33;q21), add(21)(p11); and case 3, 44,XY,add(1)(p36), del(1)(p13p22),add(6)(p25), del(7) (q22q32),del(10)(q21),add(11)(q13),-17,-18. The cytogenetic findings strongly suggest that synovial chondro-matosis is a clonal proliferation. Apart from a near-diploid chromosome number, the only recurrent cytogenetic features among the four cases were loss of band 10q26 and rearrangements of 1p13 and 12q13, found in two cases each. While chromosome bands 1p13 and 10q26 have not been reported to be involved in other types of benign chondromatous lesions, the 12q13-15 segment is recurrently rearranged in a variety of chondromatous tumours, e.g. pulmonary chondroid hamartomas. The present finding of translocations affecting band 12q13 in two of the cases emphasises that, irrespective of the anatomical localisation of the tumours, rearrangements of genes in 12q13-15 are important in the development of a large subset of benign and malignant cartilage-forming tumours.

Frequent loss of heterozygosity for markers on chromosome arm 10q in chondrosarcomas

Many tumors exhibit loss of heterozygosity (LOH) for polymorphic markers in regions of the genome that contain genes whose normal function can suppress tumor growth. Mapping of regions of LOH can help identify putative tumor suppressor loci that play a role in the pathogenesis of a disease. We evaluated 18 chondrosarcomas for LOH at 17 short tandem-repeat polymorphism loci on chromosome 10. Sixty-seven percent of the tumors (12/18) showed LOH for at least one marker and in most of these tumors the region of loss spanned all or large portions of the chromosome. By determining the smallest segment consistently involved, we identified a 7-12 cM critical region for LOH in the proximal long arm. This genomic region contains the RET oncogene, which has been implicated in the pathogenesis of multiple endocrine neoplasia types 2A and 2B, Hirschsprung disease, and medullary and papillary thyroid carcinomas. LOH on chromosome arm 10q was found in early-stage chondrosarcomas and did not correlate with grade or prognosis. Inactivation or alteration of a gene located at this site may be an early event in the development of these tumors.

t(4;19)(q35;q13.1): a recurrent change in primitive mesenchymal tumors?

We report an apparently balanced t(4;19)(q35;q13.1) as the sole cytogenetic change in a highly malignant extraskeletal sarcoma in a 12-year-old-boy. Tumor cells were negative for all immunocytochemical markers except vimentin and neuron-specific enolase. Electron microscopy indicated chondroblastic differentiation. The tumor was categorized as a malignant sarcoma with differentiation toward extraskeletal mesenchymal chondrosarcoma. Reports of a similar translocation in an embryonal rhabdomyosarcoma (RMS) and in a dedifferentiated sarcoma with both rhabdomyosarcomatous and osteosarcomatous elements suggest that this translocation can arise in a primitive mesenchymal stem cell that can differentiate along at least these three pathways.

Cytogenetic study of extraskeletal mesenchymal chondrosarcoma. A case report

Extraskeletal mesenchymal chondrosarcoma (EMC) is a rare and highly malignant type of chondrosarcoma of soft tissue origin. We performed a cytogenetic study on a patient with EMC. Cytogenetic analysis revealed the tumor karyotype: 48-49,XX, t(4;9)(q23;q22), add(10)(q?26), +16, ?del(19)(p13), +1-2mar[cp12] / 48-50,idem, t(1;20)(q21;q13), +mar[cp6] / 46,XX [7].

Complex cytogenetic rearrangement in a case of unicameral bone cyst

Cytogenetic analysis of a unicameral bone cyst surgically resected in an 11-year-old boy revealed a highly complex clonal structural rearrangement involving chromosomes 4, 6, 8, 16, 21, and both 12. These findings reinforce the need for further studies on unicameral bone cysts to verify the frequency and to understand the significance of chromosome anomalies in this type of lesion.

Mapping of the translocation breakpoints of primary pleomorphic adenomas and lipomas within a common region of chromosome 12

Recent molecular cytogenetic analysis of uterine leiomyoma cell lines with chromosomal aberrations of 12q14-q15 have indicated that the chromosome 12 breakpoints cluster in a 445-kb region designated ULCR12 (uterine leiomyoma cluster region of the chromosome 12 breakpoints). Here we report the results of FISH studies of five primary pleomorphic adenomas and six primary lipomas and established cell lines of these tumor types characterized by translocations involving the chromosomal segment 12q13-q15. The results reveal that for nearly all tumors and cell lines analyzed, the chromosome 12 breakpoints map within a 350-kb region included in ULCR12, despite the previous cytogenetic assignment of the breakpoints to different bands of that region. In some cases the primary material and additionally analyzed cell lines allowed an even more precise localization of the breakpoints to less than 100 kb. Furthermore, a previously hidden translocation of ULCR12 in one primary tumor could be detected by FISH.

Regional fine mapping of the multiple-aberration region involved in uterine leiomyoma, lipoma, and pleomorphic adenoma of the salivary gland to 12q15

Cytogenetic aberrations involving 12q13-15 are frequently observed in a variety of benign solid tumors. Using a chromosome walking approach combined with fluorescence in situ hybridization analysis, we were able to show that the chromosome 12 breakpoints involved in uterine leiomyoma, pleomorphic adenoma of the salivary gland, and lipoma cluster to the same chromosomal region, which we therefore designated MAR (multiple-aberration region). By comparing the G-banding pattern of prometaphase chromosomes of amniotic fluid cells and lymphocytes to the position of hybridization signals obtained with a cosmid pool encompassing this breakpoint hot spot region, MAR was assigned to 12q15. We conclude that, despite the cytogenetic breakpoint assignment to the three bands 12q13-15 in individual uterine leiomyomas, lipomas, and pleomorphic adenomas of the salivary glands in the past, most likely 12q15 is the only 12q breakpoint site in these three distinct solid tumor types.

Mesenchymal chondrosarcoma. A cytogenetic, immunohistochemical and ultrastructural study

A case of mesenchymal chondrosarcoma was studied. The tumor was near-tetraploid and the clonal structural chromosomal abnormalities included add(7)(p13), add(22)(q13), markers, and double minutes. The ultrastructural and immunohistochemical findings were consistent with the diagnosis. Strong immunoreactivity for desmin was an unusual, not previously reported, feature of the neoplasm.

Chondrosarcoma of bone. A clinical and DNA flow cytometric study

Fifty-two patients with chondrosarcoma were treated in our hospital between 1981 and 1992. Tumours from 21 of the patients were histologically grade I, 19 were grade II, 10 were grade III and two were grade IV. Forty-seven patients were treated surgically and samples for flow cytometric DNA analysis were taken from 38 tumours with a successful measurement in 37 cases. The mean follow-up time was 40 months and during this period 17 of the patients treated surgically developed a local recurrence or metastasis. In one case, a highly anaplastic sarcoma developed after radiation treatment. Only two of the 19 diploid tumours recurred, whereas eight of the 18 aneuploid tumours showed a recurrence. These results indicate that DNA flow cytometry is of prognostic significance in chondrosarcoma and may aid in planning the treatment.

Disruption of the architectural factor HMGI-C: DNA-binding AT hook motifs fused in lipomas to distinct transcriptional regulatory domains

Lipomas are one of the most common mesenchymal neoplasms in humans. They are characterized by consistent cytogenetic aberrations involving chromosome 12 in bands q14-15. Interestingly, this region is also the site of rearrangement for other mesenchymally derived tumors. This study demonstrates that HMGI-C, an architectural factor that functions in transcriptional regulation, has been disrupted by rearrangement at the 12q14-15 chromosomal breakpoint in lipomas. Chimeric transcripts were isolated from two lipomas in which HMGI-C DNA-binding domains (AT hook motifs) are fused to either a LIM or an acidic transactivation domain. These results, identifying a gene rearranged in a benign neoplastic process that does not proceed to a malignancy, suggest a role for HMGI-C in adipogenesis and mesenchyme differentiation.