2014 Volume 66 Issue 1 Pages 30-35
Malignant transformation of leiomyoma is rare. Here, we report the case of leiomyosarcoma localized in a pedunculated subserosal leiomyoma, which rapidly deteriorated. A 47-year-old woman (1 gravid, 1 para) suffering from right lower abdominal pain visited a clinic. She was subsequently referred to our hospital because of the presence of a large lower abdominal mass. Ultrasonography revealed a 20 cm tumor lesion in the abdominal cavity. MRI revealed a 22×19×19 cm tumor on the uterine fundus, while T1/T2-weighted imaging revealed some highly intensified cystic areas. The tumor itself was a faintly enhanced tumor, but the wall surrounding the cysts were hyperintensified on the diffusion-weighted image. From these observations, although sarcoma was suspected, this case was diagnosed as degenerated leiomyoma. Intraoperative examination revealed that, the tumor had grown on the right anterior uterine wall with a pedicle that twisted 180 degrees. No disseminated lesions were found on the peritoneum. Cytological examination of a small amount of bloody ascetic fluid was negative. Tumorectomy and total hysterectomy with bilateral salpingo-oophorectomy were performed. The patient was pathologically diagnosed with leiomyosarcoma localized in a pedunculated leiomyoma, pT1b. The sarcoma was localized only in the cystic walls, with no invasion in the pedicle. According to the clinical guideline of endometrial cancer, adjuvant chemotherapy was not performed, and she was followed up as an outpatient. Four months after the surgery, she visited our hospital with a cough and an abdominal mass. CT showed the recurrence of an 8 cm tumor in the pelvis and multiple metastatic lesions in the lungs. The best supportive care was chosen after obtaining informed consent. Thereafter she died one month later. Although the leiomyosarcoma was localized in the pedunculated subserosal leiomyoma, it relapsed promptly after surgery and the patient died of the disease. The clinical course of this patient might suggested that leiomyosarcoma localized in benign leiomyoma demonstrate highly malignant behavior and that we should perform adjuvant chemotherapy in a case with a large number of mitoses in the leiomyosarcoma. [Adv Obstet Gynecol, 66 (1) : 30-35, 2014 (H26.2)]
