title: Primary synovial sarcoma of the stomach--a case report and review of the literature.
abstract: Synovial sarcoma (SS) is a mesenchymal spindle cell tumor which displays variable epithelial differentiation. It commonly arises around the major joints or tendon sheaths in young adults, but is not commonly seen in the stomach. We experienced a case of primary gastric SS. The patient is a 22-year-old male, who presented with epigastric pain. Upper endoscopy showed an ulcer of 25 mm in diameter with marginal elevation on the posterior mid-gastric body. Biopsy of the ulcer base showed monotonous proliferation of small spindle-shaped cells on HE-stain. On immunohistochemical staining, these cells were positively stained with vimentin, cytokeratin, epithelial membrane antigen, and CD99, but were negative for KIT, CD34, desmin, and S-100 protein. These findings were compatible with SS of monophasic type. Diagnosis of primary gastric SS was made because there were no other primary lesions, nor metastatic lesions. The wedge resection was performed. Reverse transcriptase polymerase chain reaction (RT-PCR), using the RNA from frozen neoplastic tissue of the resected specimen, detected a fusion gene called SYT-SSX1, specific for SS. Though SS arising in the stomach is rare, it should be considered in the differential diagnosis of KIT-negative gastric spindle cell tumor.
authors.affiliation: Department of Gastroenterology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Sahara
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Otsuki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Egawa
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Yashiro
authors.initials: Y
authors.lastname: Yoshizawa
authors.forename: Yoshisuke
authors.initials: Y
authors.lastname: Hosoda
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D001706:Biopsy; D003937:Diagnosis, Differential; D019160:Endosonography; D005743:Gastrectomy; D005773:Gastroscopy; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011237:Predictive Value of Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013584:Sarcoma, Synovial / Q000737:chemistry / Q000150:complications / Q000235:genetics / Q000473:pathology / Q000601:surgery; D013274:Stomach Neoplasms / Q000737:chemistry / Q000150:complications / Q000235:genetics / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D015514:Oncogene Proteins, Fusion; C116512:SYT-SSX fusion protein
keywords: Endoscopic examination; Pathology; SYT-SSX; Stomach; Synovial sarcoma