Radiation-Associated Synovial Sarcoma: Clinicopathologic and Molecular Analysis of Two Cases Jean-François Egger, M.D., Jean-Michel Coindre, M.D., Jean Benhattar, Ph.D., Philippe Coucke, M.D., Louis Guillou, M.D. University Institute of Pathology (J-FE, JB, LG) and Department of Radiooncology, University Hospital (PC), Lausanne, Switzerland; Bergonié Institute and University of Bordeaux II (J-MC), Bordeaux, France region, or viscera (1, 2). SS bears the t(X;18) (SYT- Development of a soft-tissue sarcoma is an infre- SSX) reciprocal translocation that seems to be spe- quent but well-known long-term complication of cific for this tumor type and can be routinely de- radiotherapy. Malignant fibrous histiocytomas, ex- tected in paraffin-embedded tissue using the traskeletal osteosarcomas, fibrosarcomas, malig- reverse transcriptase–polymerase chain reaction nant peripheral nerve sheath tumors, and angiosar- (RT-PCR; 3–6). Radiation-associated sarcomas are comas are most frequently encountered. Radiation- an infrequent but well-known long-term complica- associated synovial sarcomas are exceptional. We tion of radiotherapy (7–16). They occur in about report the clinicopathologic, immunohistochemi- 1/1000 patients who have undergone radiation cal, and molecular features of two radiation- therapy (7–11). Radiation-associated sarcomas are associated synovial sarcomas. One tumor developed defined as sarcomas arising in a previously irradi- in a 42-year-old female 17 years after external irra- ated field after a latency period of Ն2 years (12). diation was given for breast carcinoma; the other They usually show a more aggressive clinical course occurred in a 34-year-old female who was irradiated associated with shortened patient survival as com- at the age of 7 years for a nonneoplastic condition of pared with sporadic sarcomas (9–12, 14). High- the left hand. Both lesions showed morphologic fea- grade pleomorphic sarcomas including so-called tures of monophasic spindle cell synovial sarcoma, malignant fibrous histiocytomas, extraskeletal os- were immunoreactive for cytokeratins, epithelial teosarcomas, and fibrosarcomas are the histologi- membrane antigen, CD99, CD117 (c-kit), and bcl-2 cal types most frequently encountered; extraskel- and bore the t(X;18) (SYT-SSX1) translocation. We etal chondrosarcomas, malignant schwannomas, conclude that synovial sarcoma has to be added to leiomyosarcomas, and angiosarcomas are much the list of radiation-associated soft-tissue sarcomas. rarer (7, 9–12, 14–16). Postradiation SS is excep- tional. To our knowledge, only two cases have been KEY WORDS: Cytogenetics, Molecular biology, Pa- previously described (17, 18), of which one only was thology, Radiation-associated sarcoma, Radiation fully documented and bore the t(X;18) (SYT-SSX) therapy, RT-PCR, Synovial sarcoma, Translocation. translocation (18). In the present study, we describe Mod Pathol 2002;15(9):998–1004 two additional cases of radiation-associated SS. They occurred in previous radiation fields after la- Accounting for 10 to 15% of soft tissue sarcomas, tent periods of 17 and 27 years and showed classical synovial sarcoma (SS) is a relatively rare neoplasm histologic, immunohistochemical, and molecular that occurs predominantly in adolescents or young features of SS. adults and presents as a large, deep-seated, limb- based mass, often in close association with large joints (knees and hips; 1, 2). Occasionally, it devel- CASE REPORTS ops in older patients and/or involves unusual sites such as the abdominal wall, the head and neck Case 1 A 25-year-old white woman presented in 1981 Copyright © 2002 by The United States and Canadian Academy of with a painless 4.5-cm mass located in the su- Pathology, Inc. VOL. 15, NO. 9, P. 998, 2002 Printed in the U.S.A. praareolar region of the right breast. There were no Date of acceptance: May 21, 2002. palpable axillary lymph nodes. A right mastectomy Address reprint requests to: Louis Guillou, M.D., Institut Universitaire de Pathologie, rue du Bugnon 25, 1011 Lausanne, Switzerland; e-mail: with lympadenectomy was performed in June 1981, [email protected]; fax: 41-21-314-7207. and a pathologic diagnosis of poorly differentiated DOI: 10.1097/01.MP.0000026616.41545.FF (Grade 3) invasive ductal carcinoma of the breast 998 with concomitant axillary lymph node metastases bedded in paraffin. Four-␮m-thick sections were was rendered. Subsequently, she received a total stained with hematoxylin and eosin. The mitotic dose of 50 Gy to her right breast area, a 21-Gy boost count was performed using a 40ϫ lens (high-power to the tumor area, 52 Gy to the supraclavicular and field: 0.174 mm2). Histologic typing and subtyping axillary lymph nodes, and 48 Gy to the parasternal were performed on paraffin-embedded sections node fields. This radiotherapy regimen was given stained with hematoxylin and eosin, using the over a 2-month period without any major side ef- World Health Organization histological classifica- fects; the number of sessions was not known. Com- tion of soft tissue tumors (19). Additional sections plete remission was obtained and the patient dis- were stained with the following monoclonal and charged. After a 17-year disease-free latency period, polyclonal antibodies: cytokeratin (monoclonal, she complained of an infraclavicular mass that ap- clone AE1/AE3, diluted 1/100; Novocastra Labora- peared in the previous irradiated region. The mass tories Inc., Dedham, MA), epithelial membrane an- measured 5.5 cm in maximal diameter and was tigen (monoclonal, clone E29, diluted 1/50; Dako- situated within minor pectoral muscle, deep to the patts, Glostrup, Denmark), CD34 (monoclonal, clavipectoral fascia. It extended to the previously clone Qbend 10, diluted 1/80, Immunotech, Mar- cleared right axilla. This mass was marginally ex- seille, France), smooth muscle actin (monoclonal, cised. The patient did not received any radiother- clone 1A4, diluted 1/500, Sigma Chemical Com- apy or chemotherapy after surgery. Nineteen pany, St. Louis, MO), desmin (monoclonal, clone months later, the tumor recurred locally and was, at D33, diluted 1/40, Dakopatts), S100 protein (poly- that time, widely excised. Three months later, there clonal rabbit, prediluted/ChemMate, DAKO), CD99 was no evidence of local recurrence or distant (monoclonal, clone 013, diluted 1/20, Signet Labo- metastasis. ratories Inc., Dedham, MA), bcl-2 (monoclonal, clone bcl-2/100/D5, diluted 1/50, Novocastra Lab- oratories, Ltd, Newcastle upon Tyne, UK), and Case 2 CD117 (c-kit; polyclonal rabbit, diluted 1/50, A 34-year-old woman presented with a 2-cm DAKO). Immunostaining was performed according painless mass situated between the second and to the avidin biotin complex method of Hsu et al. third metacarpus of the left hand. The nodule grad- (20) with overnight incubation for bcl-2 antibody. ually enlarged for 7 months before she sought med- Tissue sections were submitted to microwave oven ical attention. At the age of 7 years, she had been heating before staining. All steps were performed at irradiated for a congenital hemihypertrophy of the room temperature, and diaminobenzidine was left distal extremity and left-hand gigantism caused used as a chromogen. Appropriate positive and by an angiomatous malformation. Doses and frac- negative controls were employed throughout. tions were not known. The mass of the left hand was surgically removed and proved to be, on mi- croscopic examination, a 6-cm, Grade 3 monopha- sic SS. Surgical margins were positive for tumor. RNA Extraction Because of the presence of a visible residual tumor Approximately 50 mg of tumor were removed on postoperative magnetic resonance images, a from paraffin blocks by scraping with a sterile scal- postoperative chemotherapy was given, consisting pel. The tissue samples were deparaffinized by in- of six courses of a combination of dacarbazine, cubation 5 minutes in 1 mL of xylene at 65° C; this ifosfamide, and doxorubicin followed by an ampu- reaction was repeated to remove residual paraffin. tation of the third metacarpus and finger. Patholog- After centrifugation, the tissue was washed with 1 ical examination confirmed the presence of resid- mL of 100% ethanol, followed by 1 mL of 70% ual SS. The patient refused hand amputation and ethanol. After 5 minutes of vacuum drying, the pel- thus was given a total dose of 50.4 Gy in 28 sessions let was suspended in 250 ␮L of lysis buffer (20 to the left hand. Twelve months later, left pleural mmol/L of Tris-HCl, pH 7.5; 20 mmol/L of EDTA; effusion developed. Chest radiograms and com- 1% sodium dodecyl sulfate; and 350–500 ␮g of pro- puted tomography films revealed pulmonary me- teinase K). The lysis buffer was preincubated at 37° tastases, including a 2-cm nodular mass in the C for 30 minutes before tissue addition. After 16 to lower lobe of the left lung. The patient currently is 48 hours’ incubation at 55° C, 750 ␮L of Trizol-LS being treated with systemic chemotherapy for her reagent (Gibco BRL, Gaithersburg, MD) was added metastatic disease. to the sample, and total RNA was extracted accord- ing to the manufacturer’s instructions. The RNA ␮ MATERIALS AND METHODS pellet was redissolved in 40 L of RNase-free water and stored at Ϫ80° C. The quantity of the isolated Tissue for light-microscopic examination was RNA was determined by absorbance at 260 and 280 fixed in 4% phosphate-buffered formalin and em- nm. Postradiation Synovial Sarcoma (J. F. Egger et al.) 999 RT-PCR Analysis Subtyping was determined in parallel by single- Approximately 5 ␮g of the extracted RNA was strand conformation polymorphism analysis. Ali- reverse transcribed into complementary DNA quots of 5 ␮L of PCR products were mixed with 5 ␮L (cDNA), at 42° C for 50 minutes, in a volume of 20 of denaturing buffer (0.1 M NaOH and 2 mM EDTA), ␮L with the specific reverse primers (65 ng of SSX-B heated at 50° C for 10 minutes.