Primary Gastric Synovial Sarcoma Mimicking a Gastrointestinal Stromal Tumor (GIST) : Gastric Synovial Sarcoma.
J Gastrointest Surg. 2018 Aug;22(8):1450-1451. doi: 10.1007/s11605-017-3657-x. Epub 2018 Jan 8. Olsen G1, Beal EW2, Pfeil S3, Dillhoff M2.
A 57-year-old woman with a history of chronic gastroesophageal reflux disease (GERD) presented to her primary care physician with worsening epigastric pain and an unintentional 22-lb weight-loss. She had previously undergone multiple esophagogastroduodenoscopies (EGDs) that demonstrated chronic inflammation of the gastroesophageal (GE) junction without metaplasia or dysplasia and multiple fundic gastric polyps. Helicobacter pylori was never detected. She had a history of diabetes mellitus and papillary thyroid cancer treated with surgery and radioactive iodine ablation. She denied smoking and endorsed occasional alcohol use. On physical exam, she demonstrated epigastric tenderness to palpation. Laboratory studies were unremarkable.
Her gastroenterologist performed an esophagogastroduodenoscopy (EGD), which demonstrated an ulcerating gastric body mass along the lesser curvature of the stomach (Fig. 1). Biopsies revealed a monomorphic spindle cell neoplasm. Immunohistochemical (IHC) staining was negative for CD117 and positive for TLE-1. Reverse transcriptase polymerase chain reaction (RT-PCR) showed an SS18/SSX2 fusion transcript, t(X;18)(p11.2;q11.2), consistent with a synovial sarcoma.
The patient was referred to a surgical oncologist. Computed tomography (CT) of the chest, abdomen, and pelvis showed no evidence of metastatic disease. The gastric mass was not well-delineated on imaging. She underwent a laparoscopic wedge resection to remove the mass using an Endo-GIA stapler with a seam guard (Fig. 2). The final pathology confirmed a 1.8-cm focally ulcerated, submucosal gastric synovial sarcoma with negative margins and no vascular invasion. Postoperatively, her symptoms improved. She will be followed with serial cross-sectional imaging for surveillance moving forward.