Ao Tadakazu, Shinto Eiji, Ichisawa Tenma, Ichio Koki, Suzuki Takafumi, Mori Shohei, Abe Hiroki, Koiwai Tomomi, Nishikawa Makoto, Nishiyama Kiyoshi, Kato Kimi, Takeo Hiroaki
Department of Surgery, Self-Defense Forces Central Hospital, Tokyo, Japan.
Department of Pathology, Self-Defense Forces Central Hospital, Tokyo, Japan.
Surg Case Rep. 2025;11(1). doi: 10.70352/scrj.cr.25-0314. Epub 2025 Sep 4.
Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that most commonly originates in the pleura but can also occur at extrapleural sites, including the abdominal cavity. Among these, primary SFT of the stomach is exceptionally rare. Due to overlapping clinical, endoscopic, and radiologic characteristics, distinguishing SFT from gastrointestinal stromal tumor (GIST) can be particularly challenging. Misdiagnosis may result in inappropriate treatment, such as unnecessary administration of imatinib. Therefore, accurate preoperative differentiation is essential for appropriate management.
A 74-year-old man was incidentally found to have a submucosal gastric tumor during a routine health checkup and was referred to our hospital for further evaluation and treatment. Upper gastrointestinal endoscopy revealed a 30-mm subepithelial lesion on the greater curvature of the gastric fundus. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) demonstrated isolated and clustered cells with ovoid to spindle-shaped nuclei. Although not definitive, the combined endoscopic and cytological findings led to a preoperative diagnosis of suspected GIST, and laparoscopy and endoscopy cooperative surgery (LECS) was subsequently performed for local resection. Histopathological examination of the resected specimen revealed an irregular proliferation of spindle cells and nuclear immunopositivity for signal transducer and activator of transcription 6 (STAT6), leading to a final diagnosis of SFT of the stomach. According to Demicco's risk stratification model, the tumor was classified as low risk. The patient underwent complete resection via LECS and has remained free of recurrence for more than 2.5 years postoperatively.
This case highlights the difficulty in differentiating SFT from GIST preoperatively and underscores the importance of obtaining sufficient tissue samples to allow for immunohistochemical analysis, particularly STAT6 staining. Recognizing gastric SFT as part of the differential diagnosis is critical to avoid misdiagnosis and ensure appropriate therapeutic decision-making.
孤立性纤维性肿瘤（SFT）是一种罕见的间叶性肿瘤，最常见于胸膜，但也可发生于胸膜外部位，包括腹腔。其中，原发性胃SFT极为罕见。由于临床、内镜及影像学特征存在重叠，将SFT与胃肠道间质瘤（GIST）区分开来可能极具挑战性。误诊可能导致不恰当的治疗，如不必要地使用伊马替尼。因此，准确的术前鉴别对于恰当的管理至关重要。
一名74岁男性在常规健康检查中偶然发现胃黏膜下肿瘤，遂转诊至我院进行进一步评估和治疗。上消化道内镜检查显示胃底大弯处有一个30毫米的上皮下病变。内镜超声引导下细针穿刺活检（EUS-FNA）显示细胞孤立且成簇，核呈卵圆形至梭形。尽管不具有确定性，但内镜及细胞学检查结果综合起来导致术前诊断为疑似GIST，随后进行了腹腔镜与内镜联合手术（LECS）以进行局部切除。切除标本的组织病理学检查显示梭形细胞不规则增生，信号转导及转录激活因子6（STAT6）核免疫阳性，最终诊断为胃SFT。根据Demicco风险分层模型，该肿瘤被分类为低风险。患者通过LECS进行了完整切除，术后超过2.5年无复发。
本病例凸显了术前将SFT与GIST区分开来的困难，并强调了获取足够组织样本以进行免疫组化分析，尤其是STAT6染色的重要性。认识到胃SFT是鉴别诊断的一部分对于避免误诊和确保恰当的治疗决策至关重要。
