Extraskeletal myxoid chondrosarcomas do not show a chondrocytic phenotype

Juxta-articular extraskeletal myxoid chondrosarcoma mistaken for a benign cyst presenting with multiple lung metastases

Extraskeletal myxoid chondrosarcoma (EMC) is a malignant cartilage neoplasm usually encountered in the proximal extremities. We report the case of a 58-year-old male who presented initially with a 3-month history of cough. Initial staging demonstrated a right upper lobe mass with bilateral pulmonary nodules and moderate tracer uptake in the right lung mass and right groin on positron emission tomography imaging. Endobronchial ultrasound biopsy confirmed a histological diagnosis of EMC for which the patient underwent right upper lobe wedge resection. Pelvic MRI revealed a peripherally enhancing juxta-articular lesion within the region of the right obturator externus bursa, which was thought initially to represent either a ganglion or paralabral cyst. However, ultrasound-guided biopsy yielded identical histology to the resected lung mass leading to the diagnosis of primary EMC in the right groin with pulmonary metastases. The patient underwent surgical excision of the right groin mass with no local recurrence on the surveillance computed tomography at 5, 12, and 18 months but eventual disease recurrence in the right groin and further progression of the pulmonary metastases at 29 months. We emphasize that the contrast enhancement pattern of EMC can mimic a benign cystic lesion, in particular, when in a juxta-articular location, which has the potential to mislead radiologists and delay diagnosis and definitive treatment.

Extraskeletal conventional chondrosarcoma of genitalia in a child- An unusual pathology for a rare tumor

INTRODUCTION AND IMPORTANCE

Chondrosarcoma is a rare malignant tumor considered as the second common sarcoma of bone following osteosarcoma. Less than 5 % of chondrosarcomas occur in children. Conventional chondrosarcoma is the most common type observed as skeletal tumors. Extraskeletal chondrosarcomas account for about 1 % of chondrosarcomas. They are almost always of myxoid or mesenchymal subtypes.

CASE PRESENTATION

A 4-year-old girl was referred with pain and palpable mass in the labia majora since 2 years of age for which she had undergone twice biopsies, reported as soft tissue enchondroma. At this time, complete excision of the lesion with negative margins was carried out. The pathology was in favor of extraskeletal chondrosarcoma of conventional type without any evidence of bone involvement.

CLINICAL DISCUSSION

Our case was a very young child with extraskeletal conventional chondrosarcoma, not reported yet in the literature. The vast majority of extraskeletal myxoid chondrosarcomas arise in the soft tissues of the extremities. The lesion in this case was located within the subcutaneous tissue of the labia majora; however, the tumor was not compatible with myxoid chondrosarcoma. Mesenchymal chondrosarcoma is another type of extraskeletal chondrosarcoma but the histopathologic patterns observed in our patient were not compatible even with the mesenchymal chondrosarcoma.

CONCLUSION

We present a unique case of extraskeletal chondrosarcoma in a child with conventional subtype which has not been reported in the literature. In addition, the lesion was assumed to arise from a previous soft tissue enchondroma of the labia majora since infancy which makes the case distinctive.

Classification of Chondrosarcoma: From Characteristic to Challenging Imaging Findings

Chondrosarcomas can be classified into various forms according to the presence or absence of a precursor lesion, location, and histological subtype. The new 2020 World Health Organization (WHO) Classification of Tumors of Soft Tissue and Bone classifies chondrogenic bone tumors as benign, intermediate (locally aggressive), or malignant, and separates atypical cartilaginous tumors (ACTs) and chondrosarcoma grade 1 (CS1) as intermediate and malignant tumors. respectively. Furthermore, the classification categorizes chondrosarcomas (including ACT) into eight subtypes: central conventional (grade 1 vs. 2–3), secondary peripheral (grade 1 vs. 2–3), periosteal, dedifferentiated, mesenchymal, and clear cell chondrosarcoma. Most chondrosarcomas are the low-grade, primary central conventional type. The rarer subtypes include clear cell, mesenchymal, and dedifferentiated chondrosarcomas. Comprehensive analysis of the characteristic imaging findings can help differentiate various forms of chondrosarcomas. However, distinguishing low-grade chondrosarcomas from enchondromas or high-grade chondrosarcomas is radiologically and histopathologically challenging, even for experienced radiologists and pathologists.

Extraskeletal myxoid chondrosarcoma: p53 and Ki-67 offer prognostic value for clinical outcome - an immunohistochemical and molecular analysis of 31 cases

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant soft tissue tumor of unpredictable clinical behavior. The morphological spectrum of EMC based on histology alone can be difficult. There is no precise immunohistochemical (IHC) profile that together with the clinical parameters is able to predict the clinical outcome. We studied 31 cases confirmed as EMC. Clinical and follow-up data were recorded. Histopathological, molecular, and IHC studies were performed. Association among histopathological parameters was assessed using a chi-square test to determine homogeneity or linear trend for ordinal variables. The Kaplan-Meier proportional risk test (log rank) was used to study the impact of the histological, IHC, and molecular factors on progression-free survival (PFS) and disease-specific survival (DSS). Most EMCs showed a typical architectural pattern. Only a few cases presented an atypical histology (higher cellularity and solid pattern). IHC positivity (focal or diffuse) was present for CDK4 (100%), STAT-6 (90%), CD117 (84%), HNK-1 (81%), SATB2 (68%), and S-100 (58%). Synaptophysin and INSM1 were expressed in 22.6% and 38.7% of cases respectively. The EWSR1::NR4A3 rearrangement was found in 19 cases and 7 tumors presented the TAF15::NR4A3 fusion. Positive surgical margins together with atypical histology and expression of p53 and Ki67 correlated with worse clinical prognosis. EMCs express several IHC markers which are also seen in other soft tissue sarcomas. The molecular detection of NR4A3 rearrangement supports the differential diagnosis. Positive surgical margins together with atypical histology and positive expression of p53 and Ki-67 seem to predict a poor clinical outcome with worse prognosis, increased rate of recurrence, metastasis, and poor overall survival.

NFATc2-rearranged sarcomas: clinicopathologic, molecular, and cytogenetic study of 7 cases with evidence of AGGRECAN as a novel diagnostic marker

NFATc2-rearranged sarcomas (NFATc2-Sarcomas) are infrequent round cell tumors characterized by EWSR1-NFATc2 fusions and FUS-NFATc2 fusions. Although our knowledge on these neoplasms has increased recently, novel diagnostic tools and more comprehensive series are still needed. Here, we describe the features of a series of seven molecularly confirmed NFATc2-Sarcomas (EWSR1-NFATc2, n = 4; FUS-NFATc2, n = 3) and demonstrate the utility of AGGRECAN immunohistochemistry for their identification. Patients were four males and three females, ranging in age from 19 to 66 years (median: 33). All were primary bone tumors (femur, n = 4; tibia, n = 2; ilium, n = 1), frequently infiltrating the surrounding soft tissues. Treatment often consisted of neoadjuvant chemotherapy and surgery. Follow-up was available for six patients (median 18 months, range 5-102 months), three patients died of disease and four patients are currently alive. Histologically, tumors consisted of monotonous round cells growing in lobules and sheets in variable amounts of fibrous to myxoid stroma. Other findings included spindle cells, corded and trabecular architecture, nuclear pleomorphism, cartilaginous differentiation, and osteoid-like matrix. Histological response to neoadjuvant chemotherapy was poor in all resection specimens available for review (n = 4). Tumors were diffusely positive for AGGRECAN and CD99 (7/7), and a subset expressed Pan-Keratin (AE1-AE3; 3/6), S100 (2/6), BCOR (2/6), ETV-4 (2/5), WT1 (2/6), and ERG (2/5). Desmin, NKX3-1, and SATB2 were negative (0/6). Diffuse AGGRECAN staining was also seen in 8/129 round cell sarcomas used for comparison, including mesenchymal chondrosarcoma (7/26) and CIC-sarcoma (1/26). Array-CGH showed complex karyotypes with recurrent deletions of tumor suppressor genes (CDKN2A/B, TUSC7, and DMD) in three FUS-NFATC2 cases and a simpler profile without homozygous losses in one EWSR1-NFATc2 case. Segmental chromosomal gains covering the loci of the fusion genes were detected in both variants. Overall, our study confirms and expands previous observations on NFATc2-sarcomas and supports that AGGRECAN is a useful biomarker of these tumors.

Relevance of the combination of external beam radiotherapy with the hypoxia-activated prodrug ICF05016 in an experimental model of extraskeletal myxoid chondrosarcoma

Currently, there is no gold standard treatment for Extraskeletal Myxoid Chondrosarcomas (EMC) making wide margin surgical resection the most effective alternative treatment. Nevertheless, in previous preclinical studies our lab demonstrated the potential of the hypoxia-activated prodrug (HAP) ICF05016 on EMC murine model inoculated with the H-EMC-SS human cell line. The aim of this study was to assess, in vivo, the relevance of the combination of this HAP with External Beam Radiotherapy (EBR). Firstly EMC-bearing mice were treated with 6 Gy or 12 Gy of EBR (single 6 MV photon). Then for combination of HAP and EBR, animals received 6 doses of ICF05016 (46.8 μmol/kg, intravenously) at 4-day intervals, with 6 Gy EBR performed 24 h after the 3rd dose of HAP. Animals were monitored throughout the study for clinical observations (tumour growth, side effects) and survival studies were performed. From tumour samples, PCNA, Ki-67 and p21 expressions were used as markers of proliferation and cell cycle arrest. Statistical significances were determined using Kruskall-Wallis and log rank tests. The radiosensitivity of the EMC model was demonstrated at 12 Gy with significant inhibition of tumour growth. Then, the HAP strategy potentiated EBR efficacy at a lower dose (6 Gy) by improving survival without generating side effects. Thus, results of this study showed the potential interest of ICF05016 for the combination with EBR in the management of EMC.

Extraskeletal myxoid chondrosarcoma: combining cytopathology with molecular testing to achieve diagnostic accuracy

INTRODUCTION

Advances in the genetics of soft tissue neoplasia have allowed for the diagnostic recognition of specific tumor types from small biopsy specimens, including those procured using the fine needle aspiration (FNA) biopsy technique. Extraskeletal myxoid chondrosarcoma (EMC) is a malignant mesenchymal neoplasm characterized by NR4A3 and, less specifically, by EWSR1 gene rearrangements. A series of EMC cytologic specimens was examined to demonstrate the diagnostic value of incorporating fluorescence in situ hybridization (FISH) testing in cytologic cases of suspected EMC.

MATERIALS AND METHODS

A search was made of our cytopathology and surgical pathology databases for cases diagnosed as EMC. FNA biopsy cytology, exfoliative cytology, imprint cytology, and FISH analysis were performed and examined using standard techniques.

RESULTS

A total of 16 cases of EMC were retrieved from 15 patients (male/female ratio, 2.8:1; mean age, 62 years). Of the 15 patients, 10 were new patients with primary tumors, 2 had locally recurrent tumors, and 4 had metastases. The sites included the extremities in 10 cases, the trunk in 4, serous effusion in 1, and a mediastinal lymph node in 1 case. The specific cytologic diagnoses were EMC (14 cases; 88%), suspicious for EMC (n = 1), and malignant cells (n = 1). All cases for which FISH testing was successfully used were specifically recognized as EMC. Aspirates and imprint smears consisted of uniformly rounded cells set in an opaque myxoid/chondromyxoid stroma (less abundant and more diaphanous in the effusion sample), sometimes arranged in short anastomosing cords. FNA of 1 case of an EMC cellular variant mimicked a malignant small rounded cell tumor.

CONCLUSION

EMC can be added to the growing list of soft tissue neoplasms that are specifically recognizable using cytopathology, coupled with judicious application of ancillary molecular testing.

Extraskeletal myxoid chondrosarcoma of the leg in a child: A case report

RATIONALE

Extraskeletal myxoid chondrosarcoma is a slow-growing soft tissue tumor of adults with a propensity for local recurrence and eventual metastasis. Only 17 pediatric and adolescent cases have been reported.

PATIENT CONCERNS

Here we present an 11-year-old boy with a 3-year history of a slowly growing painless left leg mass. Magnetic resonance imaging of the lesion revealed a subfascial well-circumscribed lesion with intramuscular extension in the medial gastrocnemius muscle of the left leg.

DIAGNOSES

He underwent wide local excision of the mass and the histomorphological and immunohistochemical findings were consistent with extraskeletal myxoid chondrosarcoma.

INTERVENTIONS

Possible radiotherapy was the further management plan.

OUTCOMES

He was in good condition with no evidence of recurrence at 6 months postsurgery.

LESSONS

Although pediatric cases of extraskeletal myxoid chondrosarcoma were reported to be aggressive, the tumor in this case demonstrated indolent behavior. Furthermore, the tumor in this case showed primitive round cell foci which adds to a previous study that especially reported this morphology in pediatric cases.

INSM1 expression and its diagnostic significance in extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma is a rare subtype of sarcoma that affects the soft tissue and bones in middle-aged and elderly adults. Its diagnosis can be challenging, with the differential diagnoses including a wide variety of mesenchymal tumors. The line of differentiation of extraskeletal myxoid chondrosarcoma has been controversial, but recent evidence suggests a neuroendocrine phenotype. INSM1 is a zinc-finger transcription factor that plays a pivotal role in neuroendocrine differentiation, and has been proposed as a promising immunohistochemical marker of neuroendocrine carcinoma. The aim of this study was to determine the prevalence of INSM1 expression in extraskeletal myxoid chondrosarcoma and to understand its significance in sarcoma diagnosis. We immunostained the representative sections of 31 NR4A3-rearranged extraskeletal myxoid chondrosarcomas and 187 histological mimics. Nuclear staining of moderate or higher intensity in at least 5% of tumor cells was considered positive. Twenty-eight of the 31 extraskeletal myxoid chondrosarcomas (90%) were positive for INSM1, providing strong evidence for neuroendocrine differentiation. The staining was diffuse (>50%) in 17 cases, with most immunopositive tumors showing at least focal strong expression. The INSM1 staining extent was not correlated with cytomorphology, synaptophysin expression, or fusion types (EWSR1 vs non-EWSR1). In contrast, INSM1 expression was negative in 94% of the 187 other mesenchymal tumors. INSM1-positive mimics comprised a small subset of chordoma (1 of 10), soft tissue myoepithelioma (1 of 20), ossifying fibromyxoid tumor (3 of 10), and Ewing sarcoma (3 of 10), among other tumor types. The majority of these cases showed labeling in <25% of the tumor cells. Although not entirely sensitive or specific, INSM1 could be a potential marker for the diagnosis of extraskeletal myxoid chondrosarcoma when molecular genetic access is limited.

Ossifying Fibromyxoid tumor of soft parts in head and neck: case report and literature review

Background

Ossifying fibromyxoid tumor of soft parts (OFMT), is a rare but morphologically distinctive neoplasm of uncertain histogenesis that most frequently affects middle-aged male adults. Clinically, it usually presents as a slowly enlarging, small, circumscribed mass, which in most cases is painless. OFMT is most frequently found within the subcutaneous tissues of extremities or trunk, and rarely in the oral/head and neck region. We present an unusual case of this tumor in the submandibular region, and, based on the current medical literatures this is probably the first case described in this anatomical location.

Case presentation

A 32-year-old male presented to our outpatient clinic with a right submandibular mass with 1-year of evolution. Excisional biopsy showed that it was characterized by ossification along the periphery of the lesion. The neoplastic cells were spindle-like with scant eosinophilic cytoplasm. These cells were arranged with uniform cell-to-cell space in a fibromyxoid stroma. Small and large clusters of calcifications were present within the tumor. Immunohistochemically, the case showed positive staining of S-100 protein, vimentin, nestin, calponin, SMA, GFAF, desmin, INI-1, caldesmon, and CD34. It also showed negative staining of CK, CK7, CK8/18, NF, and EMA. About 2% of neoplastic cells showed positive staining of Ki67. Based on these features, the final pathological diagnosis was OFMT.

Conclusions

It is hoped that a greater understanding of OFMT in the head and neck region will avoid potential misdiagnosis, and contribute to determining the correct management, which appears to be complete surgical excision with close follow-up for recurrence surveillance.

Extraskeletal Myxoid Chondrosarcoma of the Orbit

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue tumor. Numerous cases of EMC have been reported in different anatomical locations. There is currently only a single case of EMC of the orbit and that was reported in 1985. We report a second case of orbital EMC in a 34-year-old healthy male.

Extraskeletal Myxoid Chondrosarcoma of the Foot Clinically Mimicking Plantar Fibromatosis

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma usually presenting in proximal extremities of middle-aged men. The authors discuss a unique case of EMC, localized in the plantar foot of a 76-year-old woman, clinically suspected as plantar fibromatosis. It is important to avoid misdiagnosis of EMC because of their propensity for late recurrence and their metastatic potential.

Chondro-Osseous Lesions of Soft Tissue

Soft tissue lesions can contain bone or cartilage matrix as an incidental, often metaplastic, phenomenon or as a diagnostic feature. The latter category includes a diverse group ranging from self-limited proliferations to benign neoplasms to aggressive malignancies. Correlating imaging findings with pathology is mandatory to confirm that a tumor producing bone or cartilage, in fact, originates from soft tissue rather than from the skeleton. The distinction can have dramatic diagnostic and therapeutic implications. This content focuses on the gross, histologic, radiographic, and clinical features of bone or cartilage-producing soft tissue lesions. Recent discoveries regarding tumor-specific genetics are discussed.

Extraskeletal myxoid chondrosarcoma presenting as an intradural spinal mass: report of a rare clinical presentation with an emphasis on differential diagnostic considerations

Extraskeletal myxoid chondrosarcoma is a rare soft tissue neoplasm that occurs predominantly in the soft tissues of the lower extremities. Herein we present a case of a 29 year old male who presented with bilateral femoral numbness believed to be the result of prior injury to his back. A magnetic resonance imaging revealed a mass in the T4-T5 epidural space compressing the spinal cord. Laminectomy was performed and the lesion removed piecemeal. The pathology specimen consisted of multiple fragments of dura involved by a myxoid neoplasm with a nodular growth pattern. The tumor cells were arranged in anastomosing cords and strands. Individual tumor cells were small, of uniform size and shape, with small hyperchromatic nuclei and scant eosinophilic cytoplasm. Immunohistochemical stains were performed which showed the tumor cells were diffusely positive for vimentin and focally positive for EMA, S-100 protein and cytokeratin, whereas they were negative for CD34 and CD99. Fluorescence in situ hybridization (FISH) studies showed a clonal population of cells with re-arrangement of the EWSR1 locus, confirming the histologic impression of extraskeletal myxoid chondrosarcoma. This is the first report of a case of an extraskeletal myxoid chondrosarcoma arising from the dura, confirmed to have rearrangement of the EWSR1 gene by FISH. There have only been two other cases of dural based extraskeletal myxoid chondrosarcoma reported prior to our case. We also briefly review the published literature and discuss differential diagnostic considerations for this rare tumor.

Reticular schwannoma mimicking myxoid sarcoma

Reticular/microcystic schwannoma is a recently described rare distinctive variant of schwannoma with a predilection for gastrointestinal tract. Its occurrence in soft tissue is extremely rare. We report a case of reticular/microcystic variant of schwannoma in a 55-year-old Indian woman who presented with a painless slow-growing swelling in the right forearm for the past 6 months. MRI findings suggested myxoid sarcoma. However, histological and immunohistochemical findings in the excised specimen were consistent with reticular/microcystic variant of schwannoma. This case report emphasises that the diagnosis of reticular/microcystic schwannoma should always be considered in cases where myxoid sarcomas are suspected as it can mimic malignant myxoid sarcomas, clinically and radiologically, thereby avoiding aggressive intervention and overtreatment.

Extraskeletal myxoid chondrosarcoma: tumor response to sunitinib

Background

Extraskeletal myxoid chondrosarcoma (EMCS) is a rare soft tissue sarcoma of uncertain differentiation, characterized in most cases by a translocation that results in the fusion protein EWSR1-CHN (the latter even called NR4A3 or TEC). EMCS is marked by >40% incidence of metastases in spite of its indolent behaviour. It is generally resistant to conventional chemotherapy, and, to the best of our knowledge, no data have been reported to date about the activity of tirosin-kinase inhibitor (TKI) in this tumor. We report on two consecutive patients carrying an advanced EMCS treated with sunitinib.

Methods

Since July 2011, 2 patients with progressive pretreated metastatic EMCS (Patient1: woman, 58 years, PS1; Patient2: man, 63 years, PS1) have been treated with continuous SM 37.5 mg/day, on an individual use basis. Both patients are evaluable for response. In both cases diagnosis was confirmed by the presence of the typical EWSR1-CHN translocation.

Results

Both patients are still on treatment (11 and 8 months). Patient 1 got a RECIST response after 4 months from starting sunitinib, together with a complete response by PET. An interval progression was observed after stopping sunitinib for toxicity (abscess around previous femoral fixation), but response was restored after restarting sunitinib. Patient 2 had an initial tumor disease stabilization detected by CT scan at 3 months. Sunitinib was increased to 50 mg/day, with evidence of a dimensional response 3 months later.

Conclusions

Sunitinib showed antitumor activity in 2 patients with advanced EMCS. Further studies are needed to confirm these preliminary results.

Extraskeletal myxoid chondrosarcoma: a review of 23 patients treated at a single referral center with long-term follow-up

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma. Although it has been regarded as a low-grade sarcoma unassociated with tumor-related death, a recent study has suggested an insidious nature with a high propensity for relapse during a long disease course. The aim of this study was to clarify the long-term clinical features of EMC treated at a single referral center using state-of-the-art techniques.

METHODS

A retrospective review of 23 consecutive patients (10 males, 13 females; mean age 58 years) treated between 1979 and 2008 (mean follow-up; 109 months) was performed.

RESULTS

Surgery for the primary tumor was performed in 22 patients, and 7 cases recurred locally due to inadequate resection. Eleven patients had metastatic disease, either at diagnosis (3) or developing later (8). The 5/10-year overall survival rates were 91/84 %, and the 5/10-year local recurrence-free and metastasis-free survival rates for patients with localized disease were 89/62 and 89/61 %, respectively. Larger tumor size (>10 cm) and metastases at diagnosis were significant negative prognostic factors. Four patients received ifosfamide-based chemotherapy with no objective response. There was no local recurrence in three patients who underwent R1 resection followed by adjuvant radiotherapy. Clinical palliation and retarded progression of the metastatic disease were achieved in three patients who underwent radiotherapy.

CONCLUSIONS

EMC is indolent but has a high propensity for relapse over 5 years of follow-up. Definitive initial surgery and careful monitoring for a prolonged period are important. Radiotherapy seems beneficial in an adjuvant setting and as palliative therapy for metastatic disease.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Extraskeletal cartilaginous, osseous, and chordoid tumors in children and adolescents

Extraskeletal cartilaginous, osseous, and chordoid tumors are extraordinarily rare in children and adolescents. These lesions are diagnostically challenging due to their rarity and their overlap with metastatic osteosarcoma, reactive or metabolic calcifying and bone-forming masses, various pseudosarcomatous proliferations such as myositis ossificans, and other rare genetic or metabolic disorders. This article reviews the clinicopathologic features and differential diagnosis of extraskeletal cartilaginous, osseous, and chordoid neoplasms in the first two decades of life and highlights the use of diagnostic adjuncts.

Extraskeletal myxoid chondrosarcoma of the heart and review of current literature

Extraskeletal myxoid chondrosarcoma (EMS) is a rare oncologic phenomenon characterized by chondroid and neurogenic differentiation in extraskeletal locations. These tumours represent fewer than 2.5% of all soft-tissue sarcomas and are most commonly found in the lower extremities, limb girdles, distal extremities, and trunk. Their presence in cardiac tissue is exceedingly unusual; just a single case of ems metastatic to the heart has been reported, and no cases of primary cardiac EMS are known.Here, we report the case of a 26-year-old man who presented to his physician with a chest wall mass. Further evaluation led to the discovery of a large intracardiac mass with multiple end-organ growths. Complete work-up of this patient included cardiac biopsy, echocardiography, magnetic resonance imaging, positron-emission tomography, computed tomography, and fluorescence in situ hybridization studies for the translocation involving the EWSR1 gene locus (22q12). Results of the foregoing studies confirmed the diagnosis of ems, but the origin of this patient's tumours remains elusive and the contention between a primary cardiac source and cardiac metastasis has yet to be resolved.This article describes the histopathology, immunohistochemistry, and chromosomal aberrations common to ems, together with the common presenting features, natural history, and prognosis.

Soft tissue tumors associated with EWSR1 translocation

The Ewing sarcoma breakpoint region 1 (EWSR1; also known as EWS) represents one of the most commonly involved genes in sarcoma translocations. In fact, it is involved in a broad variety of mesenchymal lesions which includes Ewing's sarcoma/peripheral neuroectodermal tumor, desmoplastic small round cell tumor,clear cell sarcoma, angiomatoid fibrous histiocytoma, extraskeletal myxoid chondrosarcoma, and a subset of myxoid liposarcoma. The fusion products between EWSR1 and partners usually results in fusion of the N-terminal transcription-activating domain of EWSR1 and the C-terminal DNA-binding domain of the fusion partner, eventually generating novel transcription factors. EWSR1 rearrangement can be visualized by the means of fluorescence in situ hybridization (FISH). As soft tissue sarcomas represent a diagnostically challenging group, FISH analysis is an extremely useful confirmatory diagnostic tool. However, as in most instances a split-apart approach is used, the results of molecular genetics must be evaluated in context with morphology.

Running GAGs: myxoid matrix in tumor pathology revisited: what's in it for the pathologist?

Ever since Virchow introduced the entity myxoma, abundant myxoid extracellular matrix (ECM) has been recognized in various reactive and neoplastic lesions. Nowadays, the term "myxoid" is commonly used in daily pathological practice. But what do today's pathologists mean by it, and what does the myxoid ECM tell the pathologist? What is known about the exact composition and function of the myxoid ECM 150 years after Virchow? Here, we give an overview of the composition and constituents of the myxoid ECM as known so far and demonstrate the heterogeneity of the myxoid ECM among different tumors. We discuss the possible role of the predominant constituents of the myxoid ECM and attempt to relate them to differences in clinical behavior. Finally, we will speculate on the potential relevance of this knowledge in daily pathological practice.

Undifferentiated Perivascular Cells in Myxoid Mesenchymal Tumors: An Ultrastructural Study

The current WHO classification of soft tissue tumors is based on the lineage of differentiation of the proliferating cells. Since mature mesenchymal cells have a broad phenotypic plasticity it has been considered unnecessary to recur to a hypothetical stem cell to explain the origin of these neoplasms. In spite of this assumption, the target cell of the oncogenic mutations in mesenchymal tumors is still a controversial item. Myxoid mesenchymal tumors constitute a heterogeneous group of neoplasms sharing in an ample mucinous matrix that separates neoplastic cells and facilitates their single submicroscopic study under electron microscopy examination. The authors have studied, by electron microscopy, 74 myxoid mesenchymal tumors, including a large variety of nosologic entities, to assess their madurational gradient. In 43 of 74 cases, a common element has been found: medium-sized cells, with high nucleo-cytoplasmic ratio, lacking lineage specific features, which were arranged around the capillary vessels. In some cases, the authors were able to demonstrate gradual differentiation in these cells, as they moved away from the vessels. These features support the hypothesis that at least some mesenchymal tumors originate from perivascular undifferentiated cells. In addition, the findings might contribute to define both topographic and morphologic characteristics of adult stem mesenchymal cells.

Distinguishing chordoid meningiomas from their histologic mimics: an immunohistochemical evaluation

Chordoid meningioma, World Health Organization grade II, is an uncommon variant of meningioma with a propensity for aggressive behavior and increased likelihood of recurrence. As such, recognition of this entity is important in cases that show similar morphologic overlap with other chondroid/myxoid neoplasms that can arise within or near the central nervous system. A formal comparison of the immunohistochemical features of chordoid meningioma versus tumors with significant histologic overlap has not been previously reported. In this study, immunohistochemical staining was performed with antibodies against D2-40, S100, pankeratin, epithelial membrane antigen (EMA), brachyury, and glial fibrillary acidic protein (GFAP) in 4 cases of chordoid glioma, 6 skeletal myxoid chondrosarcomas, 10 chordoid meningiomas, 16 extraskeletal myxoid chondrosarcoma, 18 chordomas, 22 low-grade chondrosarcomas, and 27 enchondromas. Staining extent and intensity were evaluated semiquantitatively and mean values for each parameter were calculated. Immunostaining with D2-40 showed positivity in 100% of skeletal myxoid chondrosarcomas, 96% of enchondromas, 95% of low-grade chondrosarcomas, 80% of chordoid meningiomas, and 75% of chordoid gliomas. Staining with S100 demonstrated diffuse, strong positivity in all (100%) chordoid gliomas, skeletal myxoid chondrosarcomas, low-grade chondrosarcomas, and enchondromas, 94% of chordomas, and 81% of extraskeletal myxoid chondrosarcomas, with focal, moderate staining in 40% of chordoid meningiomas. Pankeratin highlighted 100% of chordoid gliomas and chordomas, 38% of extraskeletal myxoid chondrosarcomas, and 20% of chordoid meningiomas. EMA staining was positive in 100% of chordoid gliomas, 94% of chordomas, 90% of chordoid meningiomas, and 25% of extraskeletal myxoid chondrosarcomas. Brachyury was positive only in the chordomas (100%), whereas GFAP was positive only in the chordoid gliomas (100%). EMA was the most effective antibody for differentiating chordoid meningioma from skeletal myxoid chondrosarcoma, low-grade chondrosarcoma, and enchondroma, whereas D2-40 was the most effective antibody for differentiating chordoid meningioma from extraskeletal myxoid chondrosarcoma and chordoma. Our findings demonstrate that in conjunction with clinical and radiographic findings, immunohistochemical evaluation with a panel of D2-40, EMA, brachyury, and GFAP is most useful in distinguishing chordoid meningioma from chordoid glioma, skeletal myxoid chondrosarcoma, extraskeletal myxoid chondrosarcoma, chordoma, low-grade chondrosarcoma, and enchondroma. A lack of strong, diffuse S100 reactivity may also be useful in excluding chordoid meningioma. Among the neoplasms evaluated, brachyury and GFAP proved to be both sensitive and specific markers for chordoma and chordoid glioma, respectively. Of note, this study is the first to characterize the D2-40 immunoprofile in extraskeletal myxoid chondrosarcoma, results that could be of utility in differential diagnostic assessment.

Extraskeletal myxoid chondrosarcoma: a retrospective review from 2 referral centers emphasizing long-term outcomes with surgery and chemotherapy

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a genetically distinct sarcoma with a propensity for local recurrence and metastasis despite an indolent course. To the authors' knowledge, there are limited data examining chemotherapy outcomes as a guide to therapeutic decisions for unresectable disease.

METHODS

The clinical behavior and treatment responses of 87 patients with EMC who were seen at 2 institutions between 1975 and 2008 were examined.

RESULTS

The median age of the patients at the time of diagnosis was 49.5 years, with a male-to-female ratio of 2:1. For patients presenting without metastases, 37% developed local recurrence (median time of 3.3 years) and 26% developed distal recurrence (median time of 3.2 years). Approximately 13% of patients presented with metastases. The 5-year, 10-year, and 15-year overall survival rates were 82%, 65%, and 58%, respectively. Twenty-one patients received 32 evaluable courses of chemotherapy. No significant radiologic or clinical responses were noted. The median time to disease progression while receiving chemotherapy was 5.2 months. The best physician-assessed response to chemotherapy was stable disease for at least 6 months in 25% of patients, stable disease for <6 months in 41% of patients, and disease progression in 34% of patients. The estimated progression-free survival rates at 3 months, 4 months, 6 months, and 9 months were 69%, 65%, 40%, and 26%, respectively.

CONCLUSIONS

This retrospective review highlights the poor response rate to chemotherapy and emphasizes aggressive control of localized disease as the primary approach to management. Although there are biases inherent in retrospective analyses, these data provide a benchmark for time to disease progression for the study of new agents for the treatment of patients with this diagnosis.

Fluorescence in situ hybridization is a useful ancillary diagnostic tool for extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma is a rare soft tissue tumor characterized by a nodular growth pattern with eosinophilic cells usually in a reticular pattern and abundant myxoid stroma. In contrast to other myxoid sarcomas, the majority of extraskeletal myxoid chondrosarcomas harbor a balanced translocation, t(9;22)(q22;q12), that fuses EWSR1 with NR4A3 (also known as CHN). Other less common translocations involving NR4A3 have also been described. We examined the diagnostic utility of fluorescence in situ hybridization for extraskeletal myxoid chondrosarcoma using the LSI EWSR1 break-apart probe (Abbott Molecular/Vysis, Des Plaines, IL, USA). Sixteen cases of extraskeletal myxoid chondrosarcoma with formalin-fixed paraffin-embedded tissue available were retrieved (1991-2007). The mean age at time of presentation was 57 years (range, 30-78). The male to female ratio was 7:1. All cases where either consistent with or highly suggestive of the diagnosis, with most of the primary tumors occurring in the thigh, inguinal or gluteal region. Fifteen of 16 cases were analyzable, of which 14 (93%) were positive for the rearrangement of the EWSR1 locus. In this study, the vast majority of extraskeletal myxoid chondrosarcomas are associated with a rearrangement at the EWSR1 locus (22q12). Fluorescence in situ hybridization is useful to support the diagnosis of extraskeletal myxoid chondrosarcomas and may help to differentiate it from mimics such as other myxoid sarcomas, particularly in limited biopsies.

The clinical approach towards chondrosarcoma

This review provides an overview of the histopathology, classification, diagnostic procedures, and therapy of skeletal chondrosarcoma. Chondrosarcomas that arise de novo are primary chondrosarcomas, whereas chondrosarcomas developing superimposed on pre-existing benign cartilage neoplasms such as enchondromas or osteochondromas are referred to as secondary chondrosarcomas. Conventional chondrosarcomas can be categorized according to their location in bone into central, peripheral, and juxtacortical chondrosarcomas. Histological grading is related to prognosis; however, it is also subject to interobserver variability. Rare subtypes of chondrosarcoma, including dedifferentiated, mesenchymal, and clear cell chondrosarcoma, are discussed as well. Magnetic resonance imaging is necessary to delineate the extent of the intraosseous and soft tissue involvement preoperatively. Computed tomography is especially recommended in the pelvis and other flat bones where it may be difficult to discern the pattern of bone destruction and the presence of matrix mineralization. Wide, en-bloc excision is the preferred surgical treatment in intermediate- and high-grade chondrosarcoma. In low-grade chondrosarcoma confined to the bone, extensive intralesional curettage followed by local adjuvant treatment and filling the cavity with bone graft has promising long-term clinical results and satisfactory local control. Chondrosarcomas are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in attempts to achieve local control after incomplete resection. Irradiation with protons or other charged particles seems beneficial in this curative situation. Chemotherapy is only possibly effective in mesenchymal chondrosarcoma, and is of uncertain value in dedifferentiated chondrosarcoma. Potential new systemic treatment targets are being discussed.

An undifferentiated sarcoma in a rat resembling extraskeletal myxoid chondrosarcoma in man

A soft tissue tumor occurring in the inguinal subcutaneous tissue was detected in a 109-week-old male F344 rat. Macroscopically, the tumor mass showed no skeletal relationship and a gelatinous multinodular appearance. Histologically, the tumor consisted of irregular lobules separated by scant fibrous septa. In each lobule, tumor cells were arranged in cords and strands in the plentiful myxoid stroma. The tumor cells showed marked pleomorphism, and had large, round to ovoid nuclei and abundant eosinophilic cytoplasm. Mitotic figures were often seen. Myxoid stroma of the tumor contained a large amount of acid mucopolysaccharides and collagen type II, which were demonstrated by histochemistry and immunohistochemistry respectively. The tumor cells showed positive immunoreactivities for vimentin and S100 protein. Ultrastructural examination revealed that the tumor cells had a large amount of mitochondria, Golgi complex and dilated rough endoplasmic reticulum containing amorphous material, and the myxoid stroma contained collagenous fibrils and proteoglycan particles. Based on these results, the present tumor in a rat resembled extraskeletal myxoid chondrosarcoma in man.

Cytopathology of extraskeletal myxoid chondrosarcoma

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft-tissue sarcoma rarely subjected to cytologic analysis. With the exception of a few small series, the cytology literature of EMC is largely limited to single-case reports. The purpose was to evaluate the cytomorphology of 8 EMC cases as obtained by imprint/scrape cytology and fine-needle aspiration (FNA) biopsy, to review the literature, and to demonstrate the utility of cytogenetic analysis in the diagnosis of EMC.

METHODS

The cytology files were reviewed for all soft-tissue lesions signed out as chondrosarcoma, myxoid sarcoma, and EMC, and the tissue files for any cases of EMC that had corresponding cytopathology. FNA was performed using a standard technique. Scrape preparations were performed from tissue sent fresh to the laboratory for either frozen section or for special studies such as electron microscopy or tissue banking.

RESULTS

Eight cases of EMC were retrieved from 4 men and 3 women (median age = 62 years). One patient had 2 separate cytologic specimens 4.5 years apart. All patients had subsequent tissue confirmation of the diagnosis of EMC. Five individuals presented as new patients, and 2 had a prior diagnosis of EMC. Sites included 4 masses from the foot/ankle, 2 from the calf, 1 wrist mass, and 1 buttock mass. Five patients were diagnosed from FNA biopsy, whereas 3 were diagnosed using scrape slides. Five cases were correctly and categorically diagnosed by the cytologic method as EMC, 1 as chondrosarcoma favor EMC, 1 as sarcoma favor EMC, and 1 as myxoid spindle/epithelial neoplasm. Cytologic features ranged from hypocellular to highly cellular smears composed primarily of rounded cells set in an abundant myxoid stroma that varied from opaque to semitransparent and lacked vascularity or necrosis. Smears showed cells in short, sometimes anastomosing cords, but also as single cells and nondescript cell clusters. Cells displayed a monotonous uniformity in nuclear diameter and cell size. Bland nuclei with evenly dispersed chromatin displayed variably sized nucleoli, and a moderate amount of infrequently vacuolated cytoplasm. Tissue fragments of variable size were found in 5 of 5 FNA cell blocks. Fluorescence in situ hybridization (FISH) analysis using the EWSR1 probe showed a positive 22q12 translocation in 2 of 3 FNA cases that were tested. One case with negative FISH results on the cytologic preparation showed a positive translocation using the same technique in the subsequent resection specimen.

CONCLUSIONS

A confident cytologic diagnosis of EMC depends on the presence of a uniform, round to oval cell population often arranged in cords and set in an abundant myxoid/chondromyxoid background and arising in the appropriate clinical context. If positive, FISH testing (of paraffin cell blocks or cytospin preparations) is confirmatory when coupled with this cytomorphology.

Type II collagen, but not aggrecan expression, distinguishes clear cell chondrosarcoma and chondroblastoma

AIM

Chondroblastoma and clear cell chondrosarcoma are uncommon skeletal neoplasms that have a strong tendency to involve the epiphysis of long bones. They also share some overlapping histological features. Thus, it can be difficult both radiographically and histologically to distinguish these neoplasms. So far there are no immunohistochemical markers available that have been shown to be helpful in differentiating these neoplasms.

METHODS

In our study of a series of clear cell chondrosarcomas (n = 15) and chondroblastomas (n = 35), S100, vimentin, aggrecan and collagen type II were detected by immunohistochemistry.

RESULTS

We detected immunohistochemical evidence of type II collagen within both the extracellular matrix-rich (chondroid) and matrix-poor areas in all 15 cases of clear cell chondrosarcoma. In contrast, immunohistochemical analysis failed to show staining of collagen type II in any of the 35 chondroblastomas. Other markers, including S100 protein, vimentin and aggrecan proteoglycan were tested in parallel and found to be focally positive in both neoplasms.

CONCLUSION

Therefore, our data show that in cases when clear cell chondrosarcoma and chondroblastoma pose a diagnostic challenge, the presence of type II collagen in the extracellular tumour matrix significantly supports the diagnosis of clear cell chondrosarcoma and aids in distinguishing it from chondroblastoma.

The PLAGL1 gene is down-regulated in human extraskeletal myxoid chondrosarcoma tumors

In approximately 70% of human extraskeletal myxoid chondrosarcoma (EMC) tumors, a t(9;22) chromosome translocation gives rise to a fusion protein, named EWS/NOR1, containing the amino-terminal domain of EWS fused to the complete amino acid sequence of the nuclear receptor NOR1. Several observations suggest that one role of EWS/NOR1 in EMC may be to deregulate the expression of specific genes involved in the tumoral process. In order to identify these genes, we have used a CFK2 chondrogenic cell line over-expressing EWS/NOR1. A differential display analysis has identified the PLAGL1 gene as being down-regulated in the CFK2(EWS/NOR1) cell line compared to native CFK2 cells. RT-PCR analyses show that whereas the PLAGL1 mRNAs encoding the two isoforms of the protein are highly expressed in four human chondrocyte immortalized cell lines and two human chondrocyte primary cultures, they are strongly down-regulated in six EMC tumors. We conclude that down-regulation of PLAGL1 may be a significant contributing factor in the development of EMC tumors.

Extraskeletal myxoid chondrosarcoma: updated clinicopathological and molecular genetic characteristics

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft-tissue sarcoma characterized by distinctive morphological and cytogenetical features. As its name implies, EMC was believed to represent a variant of soft-tissue chondrosarcoma owing to its histological resemblance to chondroblastic tissue in the early stages of cartilage development or chondroid tumors such as skeletal chondrosarcoma. However, the chondroid nature has been a subject of controversy, and its line of differentiation remains to be determined. Consequently, the tumor is provisionally classified into a group of tumors of uncertain differentiation in the revised World Health Organization classification of tumors of soft tissue and bone. Moreover, immunohistochemical and ultrastructural features of neural or neuroendocrine differentiation have been recently reported in a subset of EMC, providing a new insight into their histogenetic nature. Chromosomal rearrangements involving 9q22, such as t(9;22)(q22;q12), and resultant NR4A3 fusion genes are tumor-type specific or pathognomotic for this entity and are assumed to play an important role in the development of EMC. Although the biological mechanisms and functions are largely unknown, the NR4A3-related pathway is considered a potential molecular target for future therapeutic intervention. Because of its protracted but resilient nature, a tenacious and long-term follow up is necessary for any patient.

Genetics of chondrosarcoma and related tumors

PURPOSE OF REVIEW

The burgeoning body of information on the genetic changes present in and underlying the development and biology of human cancers has carried implications regarding the possible genetic events that are responsible for not only the genesis of these cancers but also the hope of the cure for these cancers. Chondrosarcomas are a group of tumors that fall into this category. The purpose of this review is to summarize the genetic findings in these tumors.

RECENT FINDINGS

The histopathologic variability of chondrosarcomas is reflected in the complexity and lack of specificity of their cytogenetic and molecular genetic findings, except for extraskeletal myxoid chondrosarcomas. These are characterized in the preponderant number of cases by a translocation, t(9;22)(q22;q12), and in a small number of cases by variant translocations t(9;17)(q22;q11) and t(9;15)(q22;q21). These translocations lead to the formation of abnormal fusion genes and gene products (proteins). In each of these translocations, the CHN gene is involved, resulting in the chimeric fusion genes EWS/CHN, RBP56/CHN, and TCF12/CHN, respectively. The specific translocations and their associated molecular genetic changes are diagnostic of extraskeletal myxoid chondrosarcomas. The abnormal proteins resulting from these fusion genes aberrantly affect gene transcription and cellular signaling pathways thought to be responsible for initiating sarcoma formation. In skeletal (central) chondrosarcomas of varying histopathologic types, the cytogenetic and molecular genetic findings are variable, complex, and apparently lacking in specificity. These changes may reflect a stepwise process (or processes) of oncogenesis involving an array of genes.

SUMMARY

Although some cartilaginous tumors are characterized by specific or recurrent chromosome alterations and molecular genetic changes, much is yet to be learned about the nature and sequence of these genetics events and about their unique role in the stepwise process involved in the development and biology of each tumor type, both malignant and nonmalignant. Until such time, some of the genetic changes, particularly the presence of specific translocations, can be of definite diagnostic value.