Objective: To determine the cause and high-risk factors for the development of intestinal fistulas (IFs) after ultrasound-guided microwave ablation (MA) of abdominopelvic lesions, and to identify effective prophylactic and therapeutic actions. Methods: Clinical data were collected from patients with an IF after ultrasound-guided MA of abdominopelvic lesions in our hospital from January 1, 2010 to December 31, 2018. The cause, diagnosis, and treatment of IFs in these patients were analyzed. Results: Among 8,969 patients who underwent ultrasound-guided MA of abdominopelvic lesions, eight patients developed IF after MA, Seven patients were discharged after being cured and one died. Conclusion: Abdominopelvic lesions are close to the intestines, so histories of surgery, radiotherapy, and abdominopelvic infection are high-risk factors for IF development after MA of these lesions. Surgical treatment should be provided as soon as an IF is identified.

Rhabdomyosarcoma arising in abdomen and pelvis is an uncommon but important type of soft tissue sarcoma, posing a great challenge for clinicians. Sporadic cases of intra-abdominal rhabdomyosarcoma were reported, but mostly in pediatrics. We demonstrated a rare case of primary abdominopelvic rhabdomyosarcoma in an elderly woman who presented with a notable increase in abdominal circumference and constipation. Abdominal magnetic resonance imaging showed a huge mass throughout the abdomen and pelvis. Cytoreductive surgery was performed by gynecologists due to the suspicious diagnosis of disseminated leiomyosarcoma. However, the final pathological analysis revealed embryonal rhabdomyosarcoma. Although adjuvant chemotherapy was administered, localized recurrence was identified 6 months after the initial operation. Gynecologists and radiologists should be aware of it so it can be listed in the differential diagnosis of masses that primarily arise in the abdomen and pelvis.