RATIONALE: Differentiation between uterine leiomyoma and leiomyosarcoma of uterus(LMS) is often challenging, especially in the context of pregnancy, which may delay subsequent diagnosis and treatment. PATIENT CONCERNS: A 35-year-old pregnant woman was found to have uterine fibroids based on preand prenatal ultrasound findings, and she remained asymptomatic. Due to the large tumor size, which affected fetal delivery and incision closure, she underwent cesarean section combined with myomectomy. Postoperative pathology revealed LMS. Further CT scans indicated pulmonary metastases, leading to a diagnosis of stage IVB LMS. Subsequently, the patient underwent laparoscopic total hysterectomy with bilateral salpingo-oophorectomy, pelvic lymphadenectomy, peritoneal biopsies, and omental sampling. The patient remains under follow-up. DIAGNOSES: The diagnosis was made based on postoperative pathology and relevant imaging findings. INTERVENTIONS: The patient was treated with surgery and chemotherapy. OUTCOMES: The patient underwent surgery and chemotherapy, and was still under follow-up. LESSONS: Attention should be paid to the diagnosis of LMS in the context of pregnancy. When facing a fibroid of uncertain nature during cesarean section, it is necessary to assess whether myomectomy is feasible and whether intraoperative autologous blood transfusion can be performed. Therefore, timely diagnosis through comprehensive clinical and imaging findings is essential to avoid misdiagnosis and ensure prompt intervention.
Lin et al. (2026) studied this question.