Department of Surgical Pathology, Hyogo College of Medicine, 1-1 Mukogawacho, 663-8501, Nishinomiya, Hyogo, Japan.
Upper Gastrointestinal Division, Department of Surgery, Hyogo College of Medicine, 1-1 Mukogawacho, 663-8501, Nishinomiya, Hyogo, Japan.
Diagn Pathol. 2021 Dec 13;16(1):115. doi: 10.1186/s13000-021-01175-3.
Synovial sarcomas are a rare type of high-grade sarcomas with unknown cell origin. They arise predominantly in the soft tissues but rarely in the stomach. We recently encountered a rare case of minute gastric synovial sarcoma.
A 61-year-old Japanese woman was pointed out edematous erosion at the body of the stomach. Biopsy specimen showed dense proliferation of spindle-shaped tumor cells mixed with smooth muscle fibers of the muscularis mucosae. Although the definite histological diagnosis was undetermined, the patient underwent laparoscopic wedge resection of the stomach. Histological examination of the resected sample revealed that the maximum diameter of the tumor was only 6 mm and that dense proliferation of rather uniform spindle tumor cells were observed mainly in the submucosa. Immunohistochemistry showed that they were positive for pan-keratin, CD99 and TLE1. SS18-SSX fusion-specific antibody gave diffuse positive staining to the tumor cells, and analysis using mRNA extracted from paraffin sections revealed that the tumor had SS18-SSX1 fusion gene. Thus, it was diagnosed as gastric synovial sarcoma, monophasic fibrous type.
Primary synovial sarcoma of the stomach is rare and only 47 cases have been reported in the English literature to date. The maximum diameter of the lesion of our case was 6 mm which is the smallest among them.
滑膜肉瘤是一种罕见的高级别肉瘤，其细胞起源不明。它们主要发生在软组织中，但很少发生在胃中。我们最近遇到了一例罕见的微小胃滑膜肉瘤。
一位 61 岁的日本女性被指出胃部有水肿性糜烂。活检标本显示密集增生的梭形肿瘤细胞与黏膜固有层的平滑肌纤维混合。尽管明确的组织学诊断尚未确定，但患者接受了腹腔镜下胃楔形切除术。切除标本的组织学检查显示，肿瘤的最大直径仅为 6 毫米，主要在黏膜下层观察到密集增生的相当均匀的梭形肿瘤细胞。免疫组织化学显示它们对泛角蛋白、CD99 和 TLE1 呈阳性。SS18-SSX 融合特异性抗体对肿瘤细胞呈弥漫性阳性染色，使用从石蜡切片中提取的 mRNA 进行分析显示肿瘤具有 SS18-SSX1 融合基因。因此，诊断为胃滑膜肉瘤，单相纤维型。
胃原发性滑膜肉瘤罕见，迄今为止在英文文献中仅报道了 47 例。我们病例的病变最大直径为 6 毫米，是其中最小的。
