Gastric Metastasis of Uterine Leiomyosarcoma Detected During Surveillance Endoscopy and Resected by Endoscopic Submucosal Dissection After Multiple Metachronous Metastases: A Case Report.

Uterine leiomyosarcoma (uLMS) is a rare, aggressive uterine malignancy that usually metastasizes hematogenously, whereas gastrointestinal involvement is uncommon. A 69-year-old woman with uLMS treated by hysterectomy and adjuvant chemotherapy developed metachronous lung, sigmoid colon, gallbladder, and abdominal wall metastases. After treatment of these metastases, periodical surveillance endoscopy revealed a 15-mm subepithelial lesion with a shallow central depression in the lower gastric body. Endoscopic ultrasonography showed a well-defined submucosal lesion without muscularis propria invasion, and biopsy confirmed metastatic leiomyosarcoma. Endoscopic submucosal dissection (ESD) was performed, achieving en bloc resection without adverse events. This rare metachronous combination of gastric, colonic, and gallbladder metastases highlights that incidental gastric metastasis may occur during prolonged disease courses and suggests that ESD may be a useful minimally invasive option for local control of small gastric metastases.