Uterine leiomyomas are the most common benign smooth muscle tumors; they are often treated by surgical removal. Lymphocytic infiltration within the uterine leiomyoma is rare. Malignant lymphoma is the first differential diagnosis to be feared. Twenty such cases have been reported in English literature. We reported a case of a 36-year-old woman who had undergone surgery for a uterine fibroid. Macroscopically, it did not differ from typical leiomyoma. Microscopic examination showed a typical leiomyoma diffusely infiltrated by lymphocytes, with a suspicion of malignant lymphoma.