Objective: Cellular leiomyoma is characterized by significantly increased cellularity and may mimic malignant tumors. Our aim was to differentiate these from other malignant small round-cell tumors. Case Report: We report a case of cellular leiomyoma that mimicked a malignant small round-cell tumor upon frozen section examination. Conclusion: Pathologists should be aware that highly cellular leiomyomas can mimic malignant tumors especially on frozen section analysis.