A mesenchymal chondrosarcoma of a child with the reciprocal translocation (11;22)(q24;q12)

Mesenchymal Chondrosarcoma from Diagnosis to Clinical Trials

Mesenchymal chondrosarcoma (MCS) is a rare subtype of chondrosarcoma with a poor prognosis. Although these tumors are sensitive to radiotherapy/chemotherapy, the standard treatment for localized MCS is only surgical resection, and there are no established treatment guidelines for patients with advanced and metastatic MCS. Due to the low incidence of MCS, the pathology of these tumors is still unknown, and other therapeutic options are lacking. Some studies show the potential role of the PDGF/PPI3K/AKT, PKC/RAF/MEK/ERK, and pRB pathways, and BCL2 overexpression in the pathogenesis of MCS. These findings provide an opportunity to use protein kinases and BCL2 inhibitors as potential therapy in MCS. In this review, we summarize the current knowledge about MCS diagnosis and treatment options. We show the immunological and molecular biomarkers used in the diagnosis of MCS. In addition, we discuss the known prognostic and predictive factors in MCS. Finally, we present the novel trends, including targeted therapies and ongoing clinical trials using protein kinase inhibitors and the death receptor 5 (DR5) agonist, which may be the focus of future MCS treatment studies.

Biology and Management of High-Grade Chondrosarcoma: An Update on Targets and Treatment Options

This review provides an overview of histopathology, clinical presentation, molecular pathways, and potential new systemic treatments of high-grade chondrosarcomas (CS), including grade 2−3 conventional, dedifferentiated, and mesenchymal CS. The diagnosis of CS combines radiological and histological data in conjunction with patient clinical presentations. Conventional CS is the most frequent subtype of CS (85%) and represents about 25% of primary bone tumors in adults; they can be categorized according to their bone location into central, peripheral, and periosteal chondrosarcomas. Central and peripheral CS differ at the molecular level with either IDH1/2 mutations or EXT1/2 mutations, respectively. CDKN2A/B deletions are also frequent in conventional CS, as well as COL2A1 mutations. Dedifferentiated CS develops when low-grade conventional CS transforms into a high-grade sarcoma and most frequently exhibits features of osteosarcoma, fibrosarcoma, or undifferentiated pleomorphic sarcoma. Their molecular characteristics are similar to conventional CS. Mesenchymal CS is a totally different pathological entity exhibiting recurrent translocations. Their clinical presentation and management are different too. The standard treatment of CSs is wide en-bloc resection. CS are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in an attempt to achieve local control in unresectable tumors. Chemotherapy is possibly effective in mesenchymal chondrosarcoma and is of uncertain value in dedifferentiated chondrosarcoma. Due to resistance to standard anticancer agents, the prognosis is poor in patients with metastatic or unresectable chondrosarcomas. Recently, the refined characterization of the molecular profile, as well as the development of new treatments, allow new therapeutic options for these rare tumors. The efficiency of IDH1 inhibitors in other malignancies suggests that these inhibitors will be part of IDH1/2 mutated conventional CS management soon. Other treatment approaches, such as PIK3-AKT-mTOR inhibitors, cell cycle inhibitors, and epigenetic or immune modulators based on improving our understanding of CS molecular biology, are emerging.

Extraskeletal Mesenchymal Chondrosarcoma

Extraskeletal mesenchymal chondrosarcoma is a rare soft tissue sarcoma arising from soft tissues, mainly of the lower extremities, meninges, and orbits. It usually presents during the second to third decades of life, and has a slight predominance in females. Histologically, it has a typical biphasic pattern comprising small cells and islands of hyaline cartilage. It can pose a diagnostic challenge in small biopsy specimens where 1 of the 2 components can be absent. The prognosis is extremely variable; survival varies depending on the location of the tumor.

Ewing Sarcoma and the History of Similar and Possibly Related Small Round Cell Tumors: From Whence Have We Come and Where are We Going?

The diagnosis of small round cell tumors always has been extremely difficult, and our current classification systems continue to evolve. Since its initial discovery by Dr James Ewing, the historical context of what is acceptably included under the designation "Ewing sarcoma" has changed. Although Ewing sarcoma and primitive neuroectodermal tumor were both initially described in the early 20th century, these tumors were considered likely distinct entities until the end of that same century, almost 75 years later. With modern immunohistochemistry and more recent advances in molecular techniques, the understanding of Ewing sarcoma and Ewing-like tumors has improved dramatically but also raises new questions and challenges. We now know that this category of tumors is remarkably more heterogenous than initially thought, especially in regards to its cytogenetics and molecular properties, and some of these differences likely have prognostic relevance. Whether we are now expanding the spectrum of Ewing sarcoma or simply recognizing new entities is controversial. Therapeutic approaches to address these new categories and/or entities need further focus and attention. Herein, we provide a comprehensive historical perspective on Ewing sarcoma, Ewing-like tumors (CIC and BCOR-rearranged sarcomas), and related and/or similar small round cell tumors, often included in the differential diagnosis, including mesenchymal chondrosarcoma, desmoplastic small round cell tumor, and small cell osteosarcoma. We also seek to provide updates and insights into the evolving classification and clinical relevance of the Ewing family of tumors.

A Case of Mesenchymal Chondrosarcoma Arising from the Femoral Vein with 8 Years of Follow-up

Mesenchymal chondrosarcoma (MCS) is an infrequent malignancy of bone and soft tissue that is characterized by a peculiar bimorphic histologic pattern with areas of undifferentiated malignant small cells surrounding well-differentiated cartilaginous islands. Involvement of the large vessels is a rare occurrence. Here, we report a case of MCS arising from the femoral vein that was treated by wide-margin resection combined with autogenous vein revascularization and then followed up for 8 years. The long-term postoperative results showed distant metastasis to the pancreas and both lobes of the lung, without recurrence at the primary site. This case indicates that for MCS arising from the femoral vein, although wide-margin resection combined with autogenous vein revascularization may avoid recurrence at the primary site, this treatment strategy has no obvious benefit for controlling long-term distant metastases.

Primary spinal intradural mesenchymal chondrosarcoma with detection of fusion gene HEY1-NCOA2: A paediatric case report and review of the literature

Mesenchymal chondrosarcoma is an extremely rare malignant tumour that most commonly originates in the bone, but is also present in extraskeletal sites. The tumour is morphologically characterized by a biphasic pattern of small round cells and islands of cartilage. Spinal mesenchymal chondrosarcomas are even rarer and, therefore, few investigations exist regarding the biological behaviour of the tumours. In the present study, we report a case of a 10-year-old female presenting with 9 months of back pain and radiographic findings of an intradural lesion measuring 1.5 cm at the level of Th4. The tumour was completely excised and subjected to pathological analyses. Following detection of the HEY1-NCOA2 fusion gene, the tumour was morphologically and immunohistochemically defined as an intradural mesenchymal chondrosarcoma attached to the dura mater. In this study, we validate the recent identification of the fusion gene HEY1-NCOA2 in paediatric extraskeletal mesenchymal chondrosarcomas. The relevant literature is reviewed and further discussed in relation to our findings.

Chromosome aberrations and HEY1-NCOA2 fusion gene in a mesenchymal chondrosarcoma

Mesenchymal chondrosarcomas are fast-growing tumors that account for 2-10% of primary chondrosarcomas. Cytogenetic information is restricted to 12 cases that did not show a specific aberration pattern. Recently, two fusion genes were described in mesenchymal chondrosarcomas: a recurrent HEY1-NCOA2 found in tumors that had not been cytogenetically characterized and an IRF2BP2-CDX1 found in a tumor carrying a t(1;5)(q42;q32) translocation as the sole chromosomal abnormality. Here, we present the cytogenetic and molecular genetic analysis of a mesenchymal chondrosarcoma in which the patient had two histologically indistinguishable tumor lesions, one in the neck and one in the thigh. An abnormal clone with the G-banding karyotype 46,XX,add(6)(q23),add(8)(p23),del(10)(p11),+12,-15[6] was found in the neck tumor whereas a normal karyotype, 46,XX, was found in the tumor of the thigh. RT-PCR and Sanger sequencing showed that exon 4 of HEY1 was fused to exon 13 of NCOA2 in the sample from the thigh lesion; we did not have spare material to perform a similar analysis of the neck tumor. Examining the published karyotypes we observed numerical or structural aberrations of chromosome 8 in the majority of the karyotyped mesenchymal chondrosarcomas. Chromosome 8 was also structurally affected in the present study. The pathogenetic mechanisms behind this nonrandom involvement are unknown, but the presence on 8q of two genes, HEY1 and NCOA2, now known to be involved in mesenchymal chondrosarcoma tumorigenesis is, of course, suggestive.

A rare case of extraskeletal mesenchymal chondrosarcoma with dedifferentiation arising from the buccal space in a young male

Extraskeletal mesenchymal chondrosarcoma (EMCS) is a rare and aggressive pathological variant of chondrosarcoma arising from soft tissues of mainly the extremities, meninges/dura, trunk, and orbits. EMCS comprises only 2 % of all soft tissue sarcomas and only 6 % of them arise from soft tissue in the head and neck region. It usually affects in the second and third decade of life and is common in women. It runs a very rapid clinical course with distant metastases and has poor prognosis and survival rates. Histologically it has a dimorphic presentation of small round mesenchymal cells interspersed with foci of cartilaginous differentiation. Radiographically it appears as a soft tissue lobulated mass with various patterns of calcification. This is the first case of primary and recurrent EMCS originating in the buccal space with unusual features of dedifferentiation. The diagnostic challenges in this case were the inconclusive FNAC results, lack of radiographic evidence of characteristic calcifications and presence of areas of myxoid material and dedifferentiation on histopathology. The clinical, cytological, histological, immunohistochemical, radiographic, PET-CT findings and management with review of literature is presented. The diagnostic and management pitfalls of this extremely rare tumor are also discussed.

Chondrosarcoma Variants

This article presents a review of chondrosarcoma variants, with a focus on the extraordinarily rare variants of chondrosarcoma in which hyaline cartilage is not the dominant feature. Discussed are the differential diagnoses for these neoplasms, radiologic studies, gross and microscopic features, and prognosis. Summaries are provided of the key features for the major variants.

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.

Guidelines for histopathological specimen examination and diagnostic reporting of primary bone tumours

This review is intended to provide histopathologists with guidelines for clinical assessment, specimen handling and diagnostic reporting of benign and malignant primary bone tumours. Information from radiology, surgical, oncology and other clinical colleagues involved in the diagnosis and treatment of primary bone tumours should be properly assessed before undertaking a structured approach to specimen handling and histological reporting. This ensures that the information needed for planning appropriate treatment of these complex tumours is provided. Consistency in diagnostic evaluation with respect to both terminology and report content facilitates liaison at multidisciplinary bone tumour meetings and collaboration between cancer units and networks, as well as providing a common database for audit of the clinical, radiological and pathological aspects of bone tumours.

Congenital intracranial mesenchymal chondrosarcoma: case report and review of the literature in pediatric patients

In this paper we report the 1st case of a congenital intracranial mesenchymal chondrosarcoma in a 2-month-old infant, apparently present at birth. A magnetic resonance image showed a large left parietal solid mass, while microscopy revealed a mixture of undifferentiated small cells and mature hyaline cartilage islands, positive for vimentin, S-100, and CD99. A surgical excision was performed but the patient died after a few weeks as a result of a rapid relapse of the tumor. We also review the pediatric cases (in patients less than 20 years old) of extraskeletal (intracranial) mesenchymal chondrosarcomas of the literature, with a focus on the most recent cytogenetic and immunohistochemical studies.

Small Round Cell Tumors of Bone

Context.—Primary small round cell tumors of the bone are a heterogeneous group of malignant neoplasms presenting predominantly in children and adolescents. They include Ewing sarcoma/peripheral neuroectodermal tumor or Ewing family tumors, lymphoma, mesenchymal chondrosarcoma, and small cell osteosarcoma. Even though they share many morphological similarities, their unique biological and genetic characteristics have provided substantial insights into the pathology of these diverse neoplasms.

Objective.—To provide an overview of the clinical, radiologic, pathologic, and genetic characteristics of these tumors along with a pertinent review of the literature.

Data Sources.—A literature search using PubMed and Ovid MEDLINE was performed, and data were obtained from various articles pertaining to clinicopathologic, biological, and genetic findings in these tumors. Additionally, findings from rare cases have been included from author's subspecialty experience.

Conclusion.—The diagnosis of small round cell tumors can be made accurately by applying clinicopathologic criteria, as well as a panel of immunohistochemical and genetic studies in appropriate cases. Molecular genetic studies may provide further insight into the biology, histogenesis, and prognosis of these tumors.

Molecular pathology of chondroid neoplasms: part 2, malignant lesions

This is the second part of a two-part review presenting an overview of the molecular findings associated with both benign and malignant chondroid neoplasms. The first part presented a brief review of modern methods in molecular pathology, along with a review of the cytogenetic and molecular genetic findings in benign chondroid neoplasms. This second part reviews the cytogenetic and molecular genetic findings in malignant chondroid neoplasms. Clinical aspects of the various lesions are briefly discussed, and each tumor is illustrated with representative radiographic and pathologic images.

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.

Extraskeletal Intracranial Mesenchymal Chondrosarcoma: Case Report and Literature Review

We present the case of a 13-year-old girl with a huge intracranial mesenchymal chondrosarcoma. She had suffered from severe headache, diplopia, intermittent nausea and vomiting for 1 month. Neurologic examination revealed bilateral blurred optic disc margins and abducens paresis. Magnetic resonance imaging demonstrated a giant, heterogeneous, intensely enhancing mass of 7 x 8 x 6 cm, occupying the bilateral frontal and left high parietal regions and based on the anterior cerebral falx. A presumptive diagnosis of aggressive meningioma was made. The patient underwent bicoronal craniotomy and gross total resection of the tumor. Pathologic examination revealed an extraskeletal mesenchymal chondrosarcoma. She was under regular follow-up and remained free of recurrence after surgery. In addition to the current case, we review previously reported cases of extraskeletal intracranial mesenchymal chondrosarcoma and discuss treatment strategies and outcomes.

Fine-needle aspiration of adult small-round-cell tumors studied with flow cytometry

Immunophenotypic study is critical for the diagnosis of adult small-round-cell tumors (SRCTs). We describe three patients with Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) and one patient with neuroblastoma in which flow cytometry immunophenotyping (FCI) on the fine-needle aspirate (FNA) and bone marrow aspirate (BMA) demonstrated an abnormal population of cells that were CD45(-) and CD16/CD56(+). Four patients with mean age of 30 years, three male and one female, clinically suspicious for a lymphoma or SRCT are described. FNA, BMA, and biopsy specimens were obtained for routine cytologic and histologic evaluation. Fresh tissue was studied by FCI. In all cases, the cytology smears showed small cells with round nuclei, slightly irregular nuclear membranes, fine chromatin, and scant cytoplasm. FCI showed CD16/56(+) and CD45(-) neoplastic cells in all cases. In one case, 76% of these cells were CD99(+). The diagnoses of ES/PNET were confirmed by immunohistochemical, ultrastructural, and cytogenetic studies. ES/PNET in FNA and BMA can be efficiently and rapidly diagnosed by combining cytologic examination with FCI using a panel including CD45, CD16/56, and CD99.

Cytopathology of mesenchymal chondrosarcomas: a report and comparison of four patients

BACKGROUND

Mesenchymal chondrosarcoma (MC) is an infrequent neoplasm, representing approximately 1% of all chondrosarcomas. Cytologic descriptions of MCs have been confined to rare case reports. In the current report, the authors describe their experience with the cytologic features of four MCs: two primary tumors and two metastatic lesions.

METHODS

Four patients were diagnosed with MC at the authors' institution from 1994 to 2002. Three of four patients underwent fine-needle aspiration (FNA) biopsy as part of their diagnosis; in the fourth patient, imprint cytology was performed. Each tumor also received histologic confirmation.

RESULTS

The patients studied included three females and one male. In three patients, the tumor presented initially as a soft tissue mass; whereas, in the remaining patient, the MC presented in the tibia. FNA results demonstrated small, oval-to-spindled cells with high nuclear-to-cytoplasmic ratios. Cells occurred singly and in clumps in a background of basophilic extracellular matrix. Histologic examination of each lesion demonstrated biphasic tumors, including focal areas of relatively mature cartilage formation as well as a small cell population.

CONCLUSIONS

MC is a rare soft tissue tumor that occurs frequently in extraskeletal locations. FNA of these tumors can be diagnostic if the tumor is sampled appropriately and of critical features, such as the background extracellular matrix, are recognized. Given the propensity of these tumors to metastasize and the poor prognosis of patients with MC, early identification by FNA biopsy may allow earlier, more aggressive interventions.

Ewing's sarcoma: diagnostic, prognostic, and therapeutic implications of molecular abnormalities

The identification of the non-random chromosome rearrangements between the EWS gene on chromosome 22q12 and members of the ETS gene family in Ewing's sarcoma, peripheral primitive neuroectodermal tumour, Askin tumour, and neuroepithelioma has been a key advance in understanding their common histogenesis and defining the Ewing's sarcoma family of tumours (ESFT). In addition to improvements in diagnosis and potentially the stratification of patients for risk, biological investigations of these gene fusions may define targets for much needed therapeutic strategies to eliminate minimal residual disease or metastatic disease. Insight into their relation with other oncogenic events in ESFT will advance risk group analysis and ultimately may improve clinical management and survival for patients with this disease.

Practical application of molecular genetic testing as an aid to the surgical pathologic diagnosis of sarcomas: a prospective study

The strong correlation of specific reciprocal translocations with individual tumor types and the demonstration that polymerase chain reaction (PCR)-based methods can detect translocations in tissue samples have stimulated interest in the role of molecular genetic testing in diagnostic surgical pathology. To evaluate the clinical utility of PCR-based molecular analysis of soft tissue neoplasms in routine surgical pathology, 131 consecutive soft tissue tumors submitted for molecular genetic testing at a tertiary care teaching hospital were prospectively analyzed over a 36-month period. RT-PCR was used to test tumor RNA for fusion transcripts characteristic of malignant round cell tumors (including Ewing sarcoma/primitive neuroectodermal tumor, desmoplastic small round cell tumor, and alveolar rhabdomyosarcoma), spindle cell tumors (including synovial sarcoma and congenital fibrosarcoma), and fatty tumors (myxoid liposarcoma). DNA sequence analysis was used to confirm the identity of all PCR products, and the PCR results were compared with the histopathologic diagnosis. We found that sufficient RNA for RT-PCR-based testing was recovered from 96% of the 131 cases and the percentage of tumors that tested positive for the associated characteristic fusion transcript was in general agreement with those reported in the literature. DNA sequence analysis of PCR products identified both variant transcripts and spurious PCR products, underscoring the value of product confirmation steps when testing formalin-fixed, paraffin-embedded tissue. Only in rare cases did testing yield a genetic result that was discordant with the histopathologic diagnosis. We conclude that PCR-based testing is a useful adjunct for the diagnosis of malignant small round cell tumors, spindle cell tumors, and other miscellaneous neoplasms in routine surgical pathology practice.

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.

Diagnosis of soft tissue tumors by fine-needle aspiration with combined cytopathology and ancillary techniques

The diagnosis of mesenchymal neoplasm by fine-needle aspiration biopsy (FNAB) has presented a diagnostic challenge. Most reports claim an accuracy approaching 95%, but while they distinguish benign and malignant lesions, the most problematic group, the intermediary malignant group, is omitted. The purpose of this study was to determine whether rapid cytologic diagnosis of soft-tissue tumors could guide surgeons in therapeutic decisions without the need for a tissue biopsy. Ninety-four FNA cytologic specimens were examined by the National Soft Tissue Consortium of Hungary and compared with the corresponding histology. Ordinary lipomas were excluded. Morphologic evaluation was supplemented by ancillary techniques such as fluorescence in situ hybridization (FISH), DNA cytometry, and immunocytochemistry. From a practical clinicopathological point of view, the cases were grouped in the following categories: 1) tumors with definitive diagnosis: a) high-grade malignant neoplasms (high-grade sarcomas, metastatic carcinomas, lymphoma), b) tumors with precise histogenetic origin by cytogenetics, c) benign tumors; 2) tumors of questionable nature. In the first group there were 74 tumors: 22 high-grade sarcomas, six metastatic carcinomas, one malignant lymphoma, 16 malignant tumors in which the precise histogenetic origin could be established by cytogenetic studies, and 29 benign soft-tissue tumors other than lipomas. In the second group there were 20 tumors comprising benign and malignant soft tissue tumors of low grade, wherein the precise nature of the neoplasm could not be established with confidence on cytologic study, even using ancillary techniques. FNAB of soft-tissue tumors combined with ancillary techniques should be considered a viable diagnostic technique for therapeutic protocols. Although the second group is fairly large, we have reliable, well-characterized categories which provide great freedom for preoperative and surgical treatment, thus providing the best chance for healing.

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.

Mesenchymal Chondrosarcoma: A Small Cell Neoplasm with Polyphenotypic Differentiation

We analyzed the clinicoradiographic, microscopic, and immunophenotypic features of 21 tumors from 13 patients with mesenchymal chondrosarcoma (11 primary and 10 metastatic) and addressed the issue of their potential polyphenotypic differentiation. The immunophenotypic profile of the tumors was analyzed by studying the expressions of the MIC2 gene protein (p30/32(MIC2)), S-100 protein, desmin, myoD1, myogenin, myoglobin, smooth-muscle actin, cytokeratin, neuron-specific enolase, and HMB-45. The expression of p30/32(MIC2) was typically restricted to the small cell component of the mesenchymal chondrosarcoma and could be documented in 17 tumors. The cartilaginous areas were positive for S-100 protein in 20 tumors. Scattered positivity of small cells for desmin was seen in 8 cases. In 2 primary tumors from different patients (1 intraosseous and 1 extraskeletal) a diffuse expression of desmin with focal coexpression of myoD1 was present within the small cell component of the tumor. The positivity for smooth-muscle actin was documented in 2 cases. Either the small cell or cartilaginous components were at least focally positive for neuron-specific enolase in 11 tumors. All tumors were negative for myogenin, myoglobin, cytokeratins (AE1/AE3, CAM5.2) and HMB-45. This study showed that, in addition to cartilaginous differentiation, mesenchymal chondrosarcomas may exhibit focal expression of desmin. In rare cases more diffuse rhabdomyoblastic differentiation can be seen within the small cell component of the tumor. Thus, mesenchymal chondrosarcoma is another primitive neoplasm with polyphenotypic differentiation and features that overlap those of other small cell malignances of bone and soft tissue. Int J Surg Pathol 8(4):291-301, 2000

The cytogenetic and molecular characterization of benign and malignant soft tissue tumors

Cytogenetic analyses of benign and malignant soft tissue tumors have led to the description of recurrent, specific, and even pathognomonic chromosomal translocations and/or other rearrangements in most types of soft tissue tumors. The consistent karyotypic rearrangements have provided critical diagnostic information in this group of neoplasms that often presents significant diagnostic challenges to the clinician and the pathologist. These findings have also been instrumental in the characterization of the abnormalities at the molecular level. Novel genes have been isolated from the translocation junctions and the mechanisms of their deregulation identified. This has increased our understanding of the histogenesis of these tumors, paved the way for the molecular diagnosis of many sarcomas, aided in directing therapy, and also provided important prognostic information.

Primary vulvar and vaginal extraosseous Ewing's sarcoma/peripheral neuroectodermal tumor: diagnostic confirmation with CD99 immunostaining and reverse transcriptase-polymerase chain reaction

Two cases of extraosseous Ewing's sarcoma/peripheral neuroectodermal tumor arising in unusual, superficial sites are reported. One tumor involved the vaginal wall of a 35-year-old woman, and the other neoplasm arose in the dermis of the vulva in a 28-year-old woman. The tumors showed characteristic microscopic features of Ewing's sarcoma/peripheral neuroectodermal tumor with nodular monotonous proliferations of undifferentiated, small, round, hyperchromatic cells with a low mitotic index. Rare rosette-like formations were apparent only in the vulvar neoplasm. The tumors displayed intense immunoreactivity in a membranous pattern for CD99, the cell surface glycoprotein encoded by the MIC2 gene. Genetically, the tumors expressed the EWS/FLI-1 chimeric transcript, derived from the t(11;22)(q24;q12) chromosomal translocation. Both patients had localized disease treated with wide local excision; one received postoperative chemotherapy, and the other received chemotherapy and radiotherapy. To date, 18 and 19 months after diagnosis, neither patient has had clinical evidence of local recurrence or metastasis. To our knowledge, these are the first reported cases of vaginal and vulvar Ewing's sarcoma/peripheral neuroectodermal tumor, confirmed with molecular genetic analysis, in the English literature.

Diagnostic and prognostic implications of the unfolding molecular biology of bone and soft tissue tumours

Sarcomas account for approximately 1-2% of human malignant disease and are relatively uncommon. Histopathological study of these mesenchymal tumours at light microscopic and ultrastructural level may not always provide an unambiguous diagnosis. It has become apparent with the identification of increasing numbers of tumour specific genetic alterations that (cyto) genetic evaluation could become a very helpful adjunct to histopathological assessment in reaching a correct diagnosis. Thus, once the different tumour types can be accurately identified and classified, more meaningful clinical trials can be initiated to evaluate and select optimal methods of management. In addition, an increasing awareness and understanding of the molecular changes associated with, and the genetic variability in, the various tumour groups is beginning to provide important new information about clinical progression and prognosis.

Histologic prognostication in soft tissue sarcomas: grading versus subtyping or both? A comprehensive review of the literature with proposed practical guidelines

Despite the validation of many histologic grading systems for soft tissue sarcomas, none have been universally accepted. Because of the overall rarity of specific histologic sarcoma subtypes, evaluation of grading systems and their prognostic significance have tended to base the results on sarcomas as a general group, diminishing the value and significance of histologic subtyping. A representative review of the literature regarding histologic grading of soft tissue sarcomas and its relationship to histologic subtype, stage, and prognosis is analyzed and discussed. Histologic grading of many soft tissue sarcomas appears to be a valuable predictor of patient survival, as confirmed by the literature. However, accurate histologic subtyping is essential for accurate histologic grading. Histologic grading in some sarcoma subtypes is probably not applicable and may underestimate biologic behavior. Clinicians and pathologists should be aware of the limitations, prognostic significances, and relationships of histologic subtyping and histologic grading in the therapeutic management and prognostication of soft tissue sarcomas.

Primary cutaneous Ewing's sarcoma: immunophenotypic and molecular cytogenetic evaluation of five cases

Cutaneous small blue cell tumors are relatively uncommon and include primary lesions of either adnexal or neuroendocrine differentiation, as well as metastatic disease. Extraosseous Ewing's sarcoma/malignant primitive neuroectodermal tumor (MPNET) rarely may occur as a primary, superficially based neoplasm in children and young adults. We describe a series of five cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor occurring as a primary cutaneous malignancy supported diagnostically both by immunohistochemical stains and fluorescence in situ hybridization (FISH). All five cases occurred as a solitary dermal nodule and were located in the lower extremities (3 cases), the axilla (1 case), and the flank (1 case). Three of the cases were clinically polypoid. Four of the five patients were female, and age at presentation ranged form 8 to 50 years of age (median, 18 years). All five tumors consisted of nodular proliferations of monomorphous, small blue cells with round, vesicular nuclei, and scant to moderate cytoplasm that were uniformly immunoreactive for the CD99 cell surface glycoprotein in a characteristic membranous pattern. Fluorescence in situ hybridization analysis of paraffin-embedded tissue revealed that three of four tumors were positive for a chromosomal translocation involving the EWS locus at 22q12, seen in more than 90% of cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor. One case was not analyzable. All five patients were treated using local excision, and two patients additionally received postoperative chemotherapy and radiotherapy. Clinical follow-up is available in three cases (median duration, 33 months) and to date none has shown evidence of either local recurrence or metastasis. Because similar cases reported in the literature have likewise had favorable clinical courses after excision, primary cutaneous Ewing's sarcoma/malignant primitive neuroectodermal tumor may represent a clinically favorable subset of this otherwise highly aggressive neoplasm.

CD99 reactivity in mesenchymal chondrosarcoma

CD99 reactivity has been reported to be a sensitive and specific marker for Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET). However, within the group of "small round blue cell tumors," the specificity has not been extensively examined. We investigated the immunoreactivity of mesenchymal chondrosarcoma to CD99 using the O13 antibody and found reactivity in 11 of 11 (100%) of cases, specifically in the "small round blue cell" component. All cases showed strong reactivity involving more than 50% of the small round blue cells with a distinct membrane pattern of staining. Staining was either absent or focal and weak in cartilaginous areas. We conclude that mesenchymal chondrosarcoma cannot be distinguished from ES/PNET on the basis of CD99 immunoreactivity.

Mesenchymal chondrosarcoma: a clinicopathologic and flow cytometric study of 13 cases presenting in the central nervous system

BACKGROUND

Mesenchymal chondrosarcomas arising in the central nervous system are extremely rare. Morphologic features have not been found to correlate reliably with prognosis.

METHODS

Eight intracranial and five intraspinal mesenchymal chondrosarcomas were reviewed with regard to location, treatment, and long term follow-up data. The histopathologic and immunohistochemical results, including Ki-67 nuclear staining frequency, were critically reviewed, and deoxyribonucleic acid content was analyzed by flow cytometry.

RESULTS

Microscopically, all 13 cases were remarkably similar. Immunoreactivity in the small cell component included vimentin in 100% and cytokeratin and glial fibrillary acidic protein in 25% of cases. S-100 immunoreactivity was noted in the cartilaginous component of 100% of cases, and in rare cells in the small cell component along the interface. Flow cytometry of the eight tumors studied revealed a diploid pattern in six, aneuploidy in two, and a wide range of S-phase fractions (0-36.5%).

CONCLUSIONS

Review of the literature and the findings of the current series indicates that mesenchymal chondrosarcomas presenting in the brain and spinal cord pursue a progressive course that correlates most reliably with extent of surgical resection. This limited retrospective study also suggests that survival may be shorter for those patients with a high S-phase fraction and a high Ki-67 staining frequency.

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].

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.

Fusion of the EWS gene to a DNA segment from 9q22-31 in a human myxoid chondrosarcoma

Southern blot analyses revealed a rearrangement of the EWS gene in a skeletal human myxoid chondrosarcoma. Interphase fluorescence in situ hybridization (FISH) studies, using cosmid clones F7 and G9 that flank the EWS locus on 22q12, confirmed the presence of this EWS gene abnormality. Cloning the rearranged EWS DNA fragment and mapping by FISH demonstrated that the EWS gene is joined to DNA sequences localised in 9q22-31. These findings are consistent with previous cytogenetic reports of a recurrent t(9;22)(q22-31;q11-12) in the myxoid variant of chondrosarcoma and reveal involvement of the EWS gene in a fourth type of human sarcoma.