A Transanal Endoscopic Ultrasound-guided Fine-needle Aspiration Biopsy for an Intrapelvic Tumor Diagnosed as Recurrence of a Smooth Muscle Tumor of Uncertain Malignant Potential Following Uterine Morcellation

A transoral endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is a well-established tissue-sampling method. However, performing a transanal EUS-FNAB remains challenging. Uterine morcellation has emerged as a minimally invasive approach for benign tumor treatment. However, uterine myomas are heterogeneous and include malignant and indeterminate malignant cells. We herein report a rare case of intrapelvic tumor diagnosed by a transanal EUS-FNAB as a recurrence of smooth muscle tumors of uncertain malignant potential following uterine morcellation. Physicians should be aware that a previous uterine myoma resected under morcellation has the possibility of intra-abdominal recurrence. A transanal EUS-FNAB is a practical option for making a pathological diagnosis.