Background: The treatment of large pelvic masses in postmenopausal women is a challenge in clinical practice. Although ultrasound or magnetic resonance imaging can be used to determine the size and location of the mass, it is still difficult to achieve a preoperative diagnosis. The majority of cellular leiomyomas are diagnosed by histopathology after surgery. We report the differential diagnosis and surgical management of a rare case of cellular leiomyoma in the broad ligament of the uterus., Case Summary: A 52-year-old Chinese woman without sexual history was admitted to the First Affiliated Hospital of Guangzhou University of Chinese Medicine for the first time. The patient had a 1-year history of progressive abdominal enlargement as well as a 2-year history of menopause, and complained of frequent abdominal pain and low-grade fever. Computed tomography of the abdomen showed a solid cystic mass (29.4 cm × 18.8 cm × 37.7 cm) in the pelvis and abdomen. Moreover, routine blood test results indicated a baseline cancer antigen 125 (CA-125) level of 187.7 U/mL and C-reactive protein of 109.58 mg/L. Subsequently, retrograde hysterectomy and bilateral adnexectomy were performed in this patient. On histopathologic examination of the surgical specimen, a rare cellular leiomyoma in the broad ligament was diagnosed., Conclusion: Clinicians need to constantly improve diagnosis and treatment for the challenges posed during clinical assessment, differential diagnosis, and surgical management., Competing Interests: Conflict-of-interest statement: All the authors declare that they have no known competing financial interests or personal relationships that could influence the work reported in this paper., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)