A Case of Unsuspected Low-grade Endometrial Stromal Sarcoma Successfully Treated with Two Minimally Invasive Surgeries.

It is relatively uncommon to treat patients with a preoperative diagnosis of benign leiomyoma that is then unexpectedly rediagnosed as malignant in postoperative histology. We report the case of a 55-year-old woman with low-grade endometrial stromal sarcoma who had been diagnosed as having uterine leiomyoma with myxoid degeneration by preoperative magnetic resonance imaging (MRI). She underwent a laparoscopic hysterectomy. The uterus, after being placed in a retrieval bag, was transvaginally morcellated to prevent spillage of the contents, as the MRI image appeared somewhat atypical. A retrospective survey of MRI findings affirmed that the muscle tissue had the appearance of a low-intensity band-like structure: bag of worms appearance. She underwent a laparoscopic bilateral salpingo-oophorectomy and remains recurrence-free. With somewhat atypical preoperative MRI, it is essential to prevent the spillage of the tumor content as no definitive preoperative exclusion of unsuspected mesenchymal malignancies is feasible.