Minimally invasive techniques are generally applied for patients suspected of having benign fibroids if medical treatment is insufficient. On the other hand, sometimes some occult carcinomas of uterus like leiomyosarcomas may be reported for the patients' applied morcellation. This condition is rare but outcomes are clinically significant. Fragmentation of occult sarcoma in the abdominal cavity without isolation bag results in widespread and poor survival. In this article, we report a case of 37-year-old woman suffering from pain due to unexpected leiomyosarcoma. Laparoscopic myomectomy was performed with power morcellation in an isolated bag. Although isolation bag is generally reported to be preventive, recurrence of sarcoma was seen at 5th month of follow-up. Even though morcellation within a bag seems to block wide spreading, dispersion of tumor cannot be stopped and more investigations have to be done.