Background: Extraskeletal chondrosarcoma (ECS) is a malignant tumor with cells that produce a cartilage matrix; it usually arises in the peripheral long and flat bones. Literature reveals an estimated incidence of 0.09-0.11% of Radiation induced sarcomas (RIS) commonly includes osteogenic sarcomas & fibrosarcomas. Chondrosarcomas are even rarer. We report a case of second primary ECS of right buccal region, possibly radiation induced, 11 years post RT for ca post cricoid.
History & clinical picture: A 39/ female, k/c/o ca post cricoid post RT (11 years ago) with difficulty in chewing from 1 year, ulcer in right buccal region for 1 month. Clinical examination: cT4a N1 M0 lesion. CT neck: 5.8 x 4.7 x 5 cm noted in right buccal region extending to I/L retro molar trigone. Enlarged level IB lymph node. Biopsy for HPE: D/D: Extra skeletal chondroma. Low grade / well differentiated chondro sarcoma. IHC: S -100 – positive, vimentin – positive. EMA – negative. Ki67 - low. Suggestive of myxoid chondro sarcoma.
Treatment: Received 3 cycles of chemotherapy with MAID regimen. Subjective response – 75%. CT head after 3 cycles of chemotherapy: Residual 2 x 1.1 cm right buccal mucosal lesion posteriorly with lost fat planes with masseter muscle and buccal fat pad. Composite resection of buccal mucosal lesion + radical neck dissection done ↓ GA. However, patient died on day of surgery because of acute post op complications. HPE: Residual lesion of 1.5*1 cm. Microscopic: myxoid chondrosarcoma, negative margins.
Discussion: Soft-tissue sarcomas are a group of rare malignancies originating from the mesenchymal tissue, historically been described as slow-growing & late to metastasize, with 10-year survival rates ranging from 65 to 78%. The histopathological and clinical features of ECS are distinctive regardless of the site of origin. The undifferentiated stromal cells of ECS typically express CD99 and vimentin, whereas S100 is usually more focally expressed in areas of cartilaginous differentiation. ECS is an intermediate grade neoplasm with a tendency toward recurrence and metastasis. (Abramovici LC, Steiner GC, Bonar F: Myxoid chondrosarcoma of soft tissue and bone: a retrospective study of 11 cases. Hum Pathol 26: 1215-1220,1995).