Extraskeletal myxoid chondrosarcoma (EMC), a phenotypically and genotypically distinctive entity, has generally been viewed as a low-grade sarcoma. No studies regarding clinical and morphologic prognostic factors have been performed on a large series of cases with long-term follow-up because of the rarity and protracted clinical course of EMC. The clinical, morphologic, and immunohistochemical features of 117 previously unreported cases were studied and statistically analyzed. The male-to-female ratio was 2:1. The median patient age was 52 years (range, 6-89 years), and the median tumor size was 7 cm (range, 1.1-25 cm). All tumors occurred within the deep subcutis or deeper soft tissues, with 80% occurring in the proximal extremities or limb girdles and 20% in the trunk. Most initial tumor excisions were intralesional or marginal. Follow-up information was available in 99 cases (median, 9 years: range, 2 months-22 years). Forty-eight patients were disease-free, and 41 patients had evidence of disease (18 of these had died of disease). Ten additional patients survived, but their disease status was unknown. There were local recurrences in 40 (48%) of 83 patients, 23 (58%) of whom had multiple local recurrences. Metastases occurred in 35 (46%) of 76 patients. The estimated 5-, 10-, and 15-year survival rates were 90%, 70%, and 60%, respectively. All cases had histologic features characteristic of classical EMC, at least focally. Cellular foci devoid of myxoid matrix and reminiscent of chondroblastoma, Ewing's sarcoma, monophasic and poorly differentiated synovial sarcoma, fibrosarcoma, and rhabdoid tumor were identified in 29% cases. Older patient age, larger tumor size, and tumor location in the proximal extremity or limb girdle were adverse prognostic factors identified by multivariate analysis. Metastasis also adversely affected survival, although local recurrence did not. This study shows that EMC has a unique clinical course, including a high rate of local recurrence, prolonged survival after metastasis in some cases, and eventually a high rate of death due to tumor. These features distinguish EMC from low-grade sarcomas. This study shows that histologic grading is of no prognostic value in EMC because prognosis is dictated primarily by certain clinical features. Histologic recognition of classical EMC and cellular and solid, nonmyxoid variants is important, however, in view of EMC's distinctive biologic behavior.

Extraskeletal myxoid chondrosarcoma: A reappraisal of its morphologic spectrum and prognostic factors based on 117 cases

Purpose: This report presents the American Brachytherapy Society (ABS) guidelines for the use of brachytherapy for patients with soft tissue sarcoma. Methods and Materials: Members of the ABS with expertise in soft tissue sarcoma formulated brachytherapy guidelines based upon their clinical experience and a review of the literature. The Board of Directors of the ABS approved the final report. Results: Brachytherapy used alone or in combination with external beam irradiation is an established means of safely providing adjuvant local treatment after resection for soft tissue sarcomas in adults and in children. Brachytherapy options include low dose rate techniques with iridium 192 or iodine 125, fractionated high dose rate brachytherapy, or intraoperative high dose rate therapy. Recommendations are made for patient selection, techniques, dose rates, and dosages. Complications and possible interventions to minimize their occurrence and severity are reviewed. Conclusion: Brachytherapy represents an effective means of enhancing the therapeutic ratio, offering both biologic and dosimetric advantage in the treatment of patients with soft tissue sarcoma. The treatment approach used depends upon the institution, physician expertise, and the clinical situation. Guidelines are established for the use of brachytherapy in the treatment of soft tissue sarcomas in adults and in children. Practitioners and cooperative groups are encouraged to use these guidelines to formulate their treatment and dose-reporting policies. These guidelines will be modified, as further clinical results become available.

The American Brachytherapy Society recommendations for brachytherapy of soft tissue sarcomas

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.

Extraskeletal myxoid chondrosarcoma: updated clinicopathological and molecular genetic characteristics.

Background: A protocol to treat osteosarcoma of the extremity was developed at two local institutions.

Superior survival in treatment of primary nonmetastatic pediatric osteosarcoma of the extremity

Extraskeletal myxoid chondrosarcoma with non-EWSR1-NR4A3 variant fusions correlate with rhabdoid phenotype and high-grade morphology.

Background
Soft tissue sarcomas are relatively rare tumors with an aggressive natural history associated with a high propensity for local recurrence following conservative surgery. It accounts for 1.8% of all cancers seen at the Tata Memorial Hospital, Mumbai. Organ preserving surgery and tumor bed brachytherapy have revolutionized the management of soft tissue sarcomas.

Interstitial brachytherapy in soft tissue sarcomas. The Tata Memorial Hospital experience.

Extraskeletal myxoid chondrosarcoma is a rare soft-tissue sarcoma of the extremities that is considered to be indolent, but yet it has a capacity for multiple recurrences and lung metastasis. In a 23-year period, 10 cases of this rare tumor were reported in this institute. The authors studied the clinicopathologic features, including histochemical and immunohistochemical reactions, of these 10 cases, with a view to evaluate whether any constant pattern emerged. The histologic features include a lobular or nodular growth pattern, periodic acid-Schiff's stain positivity, diastase sensitivity, alian blue positivity with and without pretreatment by testicular hyaluronidase, lack of epithelial markers, and positivity for S-100 protein and vimentin. The purpose of this article is to stress that the above-mentioned features are of immense help in deineating this rare tumor from other tumors associated with myxoid and chondroid differentiation. The authors did not find any consistent relationship between site, ce...

Extraskeletal Myxoid Chondrosarcoma Clinicopathologic, Histochemical, and Immunohistochemical Study of 10 Cases

Twenty-nine patients with high-grade nonmetastatic osteogenic sarcoma of the extremities were treated with adjuvant chemotherapy following definitive surgery. Chemotherapy consisted of systemic intravenous Adriamycin and cisplatin in a sequential fashion given for six courses. Nineteen out of 29 patients are alive and continuously disease free over a follow-up period ranging from 9+ to 30+ months. The relapse-free survival was 72%, and overall survival for the entire group was 69%. Median survival is not reached yet. Six out of 29 patients relapsed, of which 1 patient is alive for 6+ months after relapse. Three patients died of chemotherapy toxicity. The results were superior to historical controls treated with surgery alone. The need for more aggressive treatment approaches is discussed.

Rajesh Badhwar

Papers

Interstitial brachytherapy in soft tissue sarcomas. The Tata Memorial Hospital experience.

Extraskeletal Myxoid Chondrosarcoma Clinicopathologic, Histochemical, and Immunohistochemical Study of 10 Cases

Adjuvant chemotherapy for osteogenic sarcoma of the extremity with sequential adriamycin and cisplatin.