Synovial Sarcoma of the Upper Digestive Tract: A Report of Two Cases with Demonstration of the X;18 Translocation by Fluorescence In Situ Hybridization Steven D. Billings, M.D., Lorraine F. Meisner, Ph.D., Oscar W. Cummings, M.D., Eduardo Tejada, M.D. Department of Pathology and Laboratory Medicine, Indiana University School of Medicine (SDB, OWC), Indianapolis, Indiana; University of Wisconsin, Department of Pathology and Laboratory Medicine and the State Laboratory of Hygiene (LFM), Madison, Wisconsin; and Department of Pathology, Indiana University School of Medicine and the Laboratory Service, Richard L. Roudebush Veterans Affairs Medical Center (ET), Indianapolis, Indiana differential diagnoses for synovial sarcoma in this Two cases of synovial sarcoma that arose in the site. Synovial sarcoma of the digestive tract may be upper digestive tract are reported. One case was a underdiagnosed, and its recognition may have im- polypoid mass that arose at the gastroesophageal portant clinical implications. Fluorescence in situ junction; the other was a large intramural mass that hybridization is helpful in making this distinction. arose in the wall of the stomach. Both cases had a classic biphasic pattern. In the stomach tumor, the KEY WORDS: Chromosomal translocation, Esopha- biphasic morphology was focal and there was an geal neoplasms, Fluorescence in situ hybridization, abrupt transition to poorly differentiated synovial Immunohistochemistry, Stomach neoplasms, Sy- sarcoma. The tumors had immunohistochemical novial sarcoma. features that were consistent with synovial sar- Mod Pathol 2000;13(1):68–76 coma. Ultrastructural evaluation of the gastro- esophageal tumor supported the diagnosis. The di- Synovial sarcomas are malignant mesenchymal tu- agnostic X;18 translocation was demonstrated by fluorescence in situ hybridization on sections from mors of uncertain histogenesis. They may be bipha- paraffin-embedded tissue in 86% and 50% of inter- sic, monophasic, or poorly differentiated. They usu- phase nuclei from the gastroesophageal and gastric ally arise in the extremities intimately related to tumor, respectively. The translocation was present tendons and bursal structures of large joints but in equal frequency in the epithelial and spindle cells rarely in the synovium. Occasionally, they arise in in the biphasic areas and the poorly differentiated the head and neck, most commonly as retropha- areas of the gastric tumor, indicating that the devel- ryngeal or parapharyngeal masses (1). opment of the more aggressive subclone was prob- We describe two cases of synovial sarcoma that ably due to genetic mutations not encompassing the arose in the upper digestive tract. One case origi- SYT-SSX gene fusion product. We are aware of only nated at the gastroesophageal junction, and the five reported cases of synovial sarcoma arising in other arose in the stomach. We are aware of five the digestive tract, all in the proximal esophagus. previously reported cases of primary synovial sar- These cases are the first reported arising in the gas- coma of the cervical esophagus (2–6), but, to our troesophageal junction and stomach and the only knowledge, synovial sarcoma involving gastro- cases of synovial sarcoma of the digestive tract in esophageal junction or stomach has not been pre- which the diagnostic translocation was demon- viously reported. Both tumors displayed histologic strated. Sarcomatoid carcinoma (carcinosarcoma) features of synovial sarcoma. Immunohistochemi- and gastrointestinal stromal tumor are the main cal staining profiles supported the diagnosis. Ultra- structural features of the gastroesophageal junction tumor were consistent with synovial sarcoma. Copyright © 2000 by The United States and Canadian Academy of Pathology, Inc. However, because of the unusual locations, cytoge- VOL. 13, NO. 1, P. 68, 2000 Printed in the U.S.A. netic studies were performed to confirm the diag- Date of acceptance: August 3, 1999. Address reprint requests to: Steven D. Billings, M.D., Department of noses. The characteristic X;18 translocation was Pathology and Laboratory Medicine, Indiana University Medical Center, demonstrated by using fluorescence in situ hybrid- University Hospital 3465, 550 North University Boulevard, Indianapolis, IN 46202-5280; fax: 317-274-5346. ization (FISH) studies on paraffin-embedded tissue. 68 MATERIALS AND METHODS turation of specimen DNA in 70% formamide at 70° C, separate denaturation of probe DNA in a micro- Formalin-fixed, paraffin-embedded tissue was wave oven for 40 seconds, and hybridization of sectioned at 4 ␮m and stained with hematoxylin probe and tumor DNA overnight in a 37° C humid- and eosin, and periodic-acid-Schiff with and with- ified chamber according to the manufacturer’s in- out diastase predigestion according to standard structions. Slides from the gastroesophageal syno- methods. vial sarcoma and an adenocarcinoma of the lung For immunohistochemical examination, sections were processed together, and 100 cells from each from both tumors were stained with monoclonal were scored blindly. Slides from the gastric tumor antibodies directed against epithelial membrane were processed in the same fashion with an adeno- antigen (EMA; Ventana, Tucson, AZ), vimentin carcinoma of the stomach as a control. If the X;18 (Ventana), CD56 (Novocastra, Newcastle upon translocation is present, one would expect a high Tyne, UK), CD57 (Becton-Dickinson, San Jose, CA), frequency of spatial association between the X and and CD99 (O13; Signet, Dedham, MA). Monoclonal 18 signals that would otherwise be randomly dis- antibodies directed against cytokeratin AE1/3 tributed within the nucleus. Because we are un- (DAKO, Carpinteria, CA) and wide-spectrum antik- aware of any report of an X;18 translocation in lung eratin polyclonal antibodies (DAKO) were used on or gastric cancer, this tissue was used to control for the gastroesophageal tumor. A cocktail of cytoker- the frequency of X and 18 signals that might be atin AE1/3 (DAKO) and CAM5.2 (DAKO) was used on the gastric tumor. Antibody dilutions were indi- closely associated by chance. A close association vidually optimized (Table 1) for use with the Ven- was defined as the distance between a red and tana automatic slide stainer (Ventana). Microwave green signal less than the width of three centromere pretreatment was used for antibodies directed signals. Random associations were defined as sig- against EMA, vimentin, CD56, CD57, CD99, and the nals more than or equal to three centromere AE1/3 and CAM 5.2 cocktail. Appropriate tissue widths. Using this methodology, we have previously served as positive controls. Negative controls were found that the frequency of close associations in carried out with the Ventana Medical Systems neg- synovial sarcoma generally exceeded 75% com- ative control reagent, mouse monoclonal antibody pared with 20% or less of tumor nuclei lacking an Clone MOPC-21Ј, which is not directed against a X;18 translocation (7). known epitope present in human tissue. For ultrastructural evaluation, tissue was fixed in 3% glutaraldehyde, postfixed in osmium tetroxide, CASE REPORTS and stained with uranyl acetate and lead citrate. The specimen was thin sectioned and examined Case 1 under a transmission electron microscope. A 47-year-old Hispanic man had a history of per- Cytogenetic evaluation was performed using sistent peptic ulcer disease and pyloric stenosis as- FISH with dual color DNA probes, a green probe for sociated with gastric outlet obstruction. He had the X centromere and a red probe for a region in the undergone repeated esophagogastroduodenosco- middle of the 18 long-arm (18q21). Hybridization pies with pyloric dilatations and standard medical with probes DXZ1 (Oncor, Gaithersburg, MD) la- therapy without significant improvement. As a re- beled with fluoroisothiocyanate for the X centro- sult of the refractory nature of his peptic ulcer dis- mere and digoxigenin-labeled 18qD18541 detected ease and gastric outlet obstruction, he underwent with rhodamine (Oncor) were performed as previ- vagotomy, antrectomy, and a Billroth II procedure. ously described (7). Briefly, this involved deparaf- During surgery, a pedunculated, polypoid mass finization, digestion with pronase for 30 min, dena- was found arising at the gastroesophageal junction. The mass was excised and submitted as a separate specimen. Histologic examination of the polypoid TABLE 1. Summary of Antibody Dilutions and Results mass revealed a biphasic tumor consistent with Antibody Dilution Case 1 Case 2 synovial sarcoma. The tumor was focally present at Vimentin 1 : 100 EϪ /Sϩ EϪ /Sϩ the surgical margin. The patient underwent a sub- CD56 1 :20 EϪ /Sϩ EϪ /Sϩ sequent completion gastrectomy with partial Ϫ Ϫ ϩ ϩ CD57 1 : 10 E /S E /S (focal) esophagectomy. Residual synovial sarcoma was not CD99 1 : 10 EϪ /SϪ EϪ /SϪ EMA 1 : 100 Eϩ /SϪ Eϩ /SϪ identified. AE1 /3 1 : 200 Eϩ /S focally ϩ not performed No adjuvant therapy was given. Follow-up eval- ϩ ϩ Polyclonal 1 : 9600 E /S focally not performed uation including roentgenograms, computerized Cytokeratin AE1 /3 ϩ CAM5.2 1 : 40 (AE1 /3) not performed Eϩ /S focally ϩ tomographic (CT) scans, and frequent esophagoje- cocktail 1 : 2 (CAM5.2) junostomy endoscopic procedures revealed no ev- EMA, epithelial membrane antigen; E, epithelial cells; S, spindle cells. idence of other primary site, metastasis, or recur- Digestive Tract Synovial Sarcoma (S.D. Billings et al.)69 rence. The patient has remained disease-free for 21 months. Case 2 A 55-year-old