1. ¹University Institute of Pathology, Lausanne, Switzerland
2. ²Department of Radiooncology, University Hospital, Lausanne, Switzerland
3. ³Bergonié Institute and University of Bordeaux II, Bordeaux, France

Correspondence: Louis Guillou, M.D., Institut Universitaire de Pathologie, rue du Bugnon 25, 1011 Lausanne, Switzerland; e-mail: louis.guillou@chuv.hospvd.ch; fax: 41-21-314-7207.

Accepted 21 May 2002.

Abstract

Development of a soft-tissue sarcoma is an infrequent but well-known long-term complication of radiotherapy. Malignant fibrous histiocytomas, extraskeletal osteosarcomas, fibrosarcomas, malignant peripheral nerve sheath tumors, and angiosarcomas are most frequently encountered. Radiation-associated synovial sarcomas are exceptional. We report the clinicopathologic, immunohistochemical, and molecular features of two radiation-associated synovial sarcomas. One tumor developed in a 42-year-old female 17 years after external irradiation was given for breast carcinoma; the other occurred in a 34-year-old female who was irradiated at the age of 7 years for a nonneoplastic condition of the left hand. Both lesions showed morphologic features of monophasic spindle cell synovial sarcoma, were immunoreactive for cytokeratins, epithelial membrane antigen, CD99, CD117 (c-kit), and bcl-2 and bore the t(X;18) (SYT-SSX1) translocation. We conclude that synovial sarcoma has to be added to the list of radiation-associated soft-tissue sarcomas.