A 19-year-old-woman had a cystic adenomyoma located within the myometrium. She complained of severe dysmenorrhea. Gonadotropin-releasing hormone agonist therapy was administered, but her dysmenorrhea was more pronounced than before treatment. Therefore, total laparoscopic resection of the lesion was performed. The external appearance of the patient's uterus was almost normal. A hydroultrasonographic monitoring method was devised (transvaginal ultrasonography with peritoneal hydration of physiologic saline) that proved useful in locating the adenomyoma. The patient's dysmenorrhea disappeared postoperatively.