滤泡树突状细胞肉瘤（FDCS）是一种罕见的间叶组织肿瘤，通常发生在淋巴结中；临床上很少见，只有偶尔出现在软组织、肝脏和脾脏以及腹膜后区的记录；在胃中发生的情况极为罕见。一名64岁的女性患者在6个月前发现左上腹部有一肿块，因剧烈腹痛而被送至医院。腹部计算机断层扫描显示贲门周围有软组织肿块。免疫组化和术后病理结果与FDCS相符合。患者接受了"全胃切除和食管空肠吻合术"（Roux-Y吻合）。患者手术后2个月康复良好。我们报道了一例发生在胃和腹腔的FDCS病例，其在临床定位、临床表现和影像征象方面具有独特性。本病例报告旨在增加临床医生对胃和腹腔中FDCS的理解和诊断，降低临床误诊率。版权所有 © 2023 作者。由Wolters Kluwer Health, Inc.出版。

Follicular dendritic cell sarcoma (FDCS) is a rare mesenchymal tumor that typically develops in lymph nodes; it is clinically uncommon and has only occasionally been documented in cases of soft tissue, liver and spleen, and retroperitoneum; it is also extremely uncommon to develop in the stomach.A 64-year-old woman who discovered a lump in her left upper abdomen 6 months prior and was taken to the hospital due to excruciating abdominal pain.An abdominal computed tomography scan showed a soft tissue mass around the cardia. The immunohistochemical and postoperative histopathology results were compatible with FDCS.The patient underwent "radical total gastrectomy and esophagojejunostomy" (Roux-Y anastomosis).The patient recovered well 2 months after surgery.We report a case of FDCS occurring in the stomach and abdominal cavity, which was unique in terms of clinical location, clinical presentation, and imaging signs. This case report aims to enhance clinicians' understanding and diagnosis of FDCS in the stomach and abdominal cavity and reduce the rate of clinical misdiagnosis.Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.