Intratubal teratoma is a very rare condition. The authors believe to present the first case of a completely intratubal mature cystic teratoma with a contralateral intraovarian teratoma. Preoperative ultrasound examination allowed the intraoperative diagnosis of this rare condition, hence allowing appropriate surgical management. Materials and Methods: A 19-year-old woman presented with a history of pelvic pain and severe dysmenorrhea. Ultrasound examination initially suggested bilateral ovarian dermoids. Upon laparoscopy, the distal left fallopian tube was obstructed and contained an inflammatory mass adhered to the rectosigmoid. The left ovary was entirely normal. A contralateral intraovarian dermoid was also identified. Conclusion: Although rare, when an intratubal mass is identified, consideration of intratubal dermoid should be given. Preoperative ultrasound can be of critical importance to the intraoperative diagnosis.