A 45-year-old multipara woman was referred due to the rapid enlargement of an asymptomatic pelvic mass that was detected during a regular check up. She had undergone laparoscopic-assisted myomectomy 15 years previously. At the time, the uncontained extraction of an intraligamental myoma with electric power morcellation had been performed. Multimodal imaging revealed a heterogeneous mass in the vesicouterine pouch that was found to be supplied by the left gastro-omental and superior vesical arteries. Although malignancy could not be completely denied, parasitic peritoneal myoma with myxoid degeneration was the most probable diagnosis. Single-port laparoscopic excision of the peritoneal mass was performed along with laparoscopic-assisted vaginal hysterectomy and bilateral salpingo-oophorectomy. The excised peritoneal mass was placed into a retrieval bag and extracted through the vagina. The pathological diagnosis was a parasitic peritoneal myoma with myxoid degeneration. The postoperative course was uneventful, and there was no recurrence of parasitic myoma in the 1-year follow up after surgery.