Case Series on Cellular Leiomyoma—Benign Mimicking Malignant

Aims and background: Cellular leiomyoma (CL) is an uncommon variant of uterine leiomyoma characterized by increased cellularity and significant morphological overlap with smooth muscle tumors of uncertain malignant potential (STUMP), leiomyosarcoma, and low-grade endometrial stromal sarcoma (LGESS).Although benign, CL is recognized for its borderline biological behavior, including an increased tendency for recurrence and rare reports of extra-uterine spread.This case series aims to describe the clinical, radiological, intraoperative, and histopathological features of patients with histologically confirmed CL managed at a tertiary care center and to compare these findings with available literature.A retrospective analysis of 20 cases of CL from January 2021 to August 2025 was done.Clinical presentation, imaging findings, surgical management, gross and microscopic pathology, and immunohistochemistry results were reviewed.Case description: Most patients (90%) presented between 30 and 50 years of age, and 85% were parous.Heavy menstrual bleeding (40%) was the most common complaint.Ultrasonography universally showed a predominantly hypoechoic uterine mass with heterogeneity due to cystic or calcific changes.Magnetic resonance imaging (MRI) in four cases suggested CL in only one, while the others were reported as fibroids with degeneration.Surgical management included abdominal hysterectomy in 12 patients, total laparoscopic hysterectomy (TLH) in 4, and myomectomy in 4 patients.Histopathologically, nine cases were diagnosed as CL, four as CL with adenomyosis, and five showed CL with degenerative changes; one patient showed CL with osseous metaplasia and one patient had a differential diagnosis of CL/LGESS.Conclusion: Due to a higher probability of recurrence, accurate differentiation using histopathology, immunohistochemistry, and advanced imaging is essential to prevent misdiagnosis and overtreatment.Clinical significance: Cellular leiomyoma is an uncommon variant of uterine leiomyoma, with a high probability of recurrence.Hence, diagnosis using histopathology, immunohistochemistry, and advanced imaging is essential to prevent misdiagnosis and overtreatment.