Three Cases of Spontaneous Parasitic Myoma

Uterine myomas are the most common benign gynecological tumors. For myomas with a typical growth pattern at an early stage, a treatment decision can be made with relative ease. However, in atypical cases, the decision is more difficult. We report 3 cases in which the preoperative diagnosis was challenging. All 3 patients underwent laparoscopic surgery for pelvic masses, which were found to be parasitic myomas.Case 1: A 31-year-old woman with no surgical history presented at our hospital for evaluation of a pelvic mass. Transvaginal ultrasonography and MRI revealed a well-circumscribed mass in contact with the left side of the uterus. The mass was excised laparoscopically. The pathological diagnosis was necrotic myoma.Case 2: A 35-year-old woman with no surgical history presented at our hospital for evaluation of a pelvic mass. Imaging via transvaginal ultrasonography and MRI revealed a well-circumscribed mass adjacent to but separate from the right anterior surface of the uterus. The mass was excised laparoscopically. The pathological diagnosis was necrotic myoma.Case 3: A 28 year-old woman with no surgical history presented at our hospital for evaluation of a pelvic mass. Imaging via transvaginal ultrasound and MRI revealed a well-circumscribed mass located to the right of the uterus. Continuity could not be determined. The mass was excised laparoscopically. The pathological diagnosis was necrotic myoma.Conclusion: Spontaneous parasitic myomas are extremely rare, and their incidence and pathogenesis are still unknown. We present 3 cases that may contribute to a further understanding of these tumors.