Endoscopic Ultrasound‐Guided Fine‐Needle Aspiration for Diagnosing Late‐Stage Pelvic Recurrence of Uterine Leiomyosarcoma 15 Years After Total Hysterectomy

ABSTRACT Endoscopic ultrasonography (EUS) facilitates high‐resolution visualization of lesions adjacent to the gastrointestinal tract. Uterine leiomyosarcoma (uLMS) is rare, aggressive, and difficult to diagnose. This report describes a rare case of pelvic recurrence of uLMS that occurred 15 years after hysterectomy, which was successfully diagnosed using endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA). Our patient was a woman in her 80s who presented with an 80‐mm pelvic mass adjacent to the rectum. Transrectal EUS‐FNA was performed using a 22‐G needle. Histopathological examination revealed atypical spindle‐shaped cells that were positive for smooth muscle actin and desmin, confirming metastatic uLMS. This case underscores two key points: (1) uLMS may recur > 10 years following complete resection, highlighting the need for long‐term surveillance; and (2) EUS‐FNA provides an accurate, minimally invasive, and safe diagnostic method for deep pelvic lesions that are otherwise inaccessible. The innovative EUS‐FNA approach expands the diagnostic and interventional frontiers of gynecological oncology beyond traditional endoscopic boundaries. Trial Registration : N/A