(130) Vaginal Dermoid Cyst - A Case Report

Background: Benign cystic teratomas (dermoid cysts) are nonmalignant germ-cell tumors that contain three well-differentiated germ cell layers (endoderm, mesoderm and ectoderm). Vaginal dermoid cysts are extremely rare, with less than ten case reports published in medical literature.

Case: A 17-year-old female presented to the ED for acute on chronic left sided pelvic pain and fullness. A transvaginal pelvic ultrasound (TVUS) identified a complex left pelvic mass. She had outpatient gynecologic follow up, including a CT scan demonstrating a 3.7 x 3.8 cm fat-containing mass in the left pelvis that appeared to be extraovarian. She underwent a diagnostic laparoscopy for removal of the suspected left dermoid cyst. During surgery, the cyst was not visualized and the surgery was aborted.
The patient continued to experience pelvic pain, dyspareunia and pain with tampon insertion. A pelvic MRI was performed for further evaluation and revealed a 4.5 x 3.5 x 3.5 cm well-circumscribed, cystic mass posterior lateral to the left aspect of the lower uterine segment/vaginal vault consistent with a dermoid cyst. See Figure 1.
A second diagnostic laparoscopy was performed, and the patient was noted to have a 2 cm cyst along her right ovary. Right cystectomy was performed. Pathology was consistent with benign corpus luteum and immature follicles.
The patient was then referred to Pediatric and Adolescent Gynecology at our institution. A pelvic exam revealed a palpable, smooth mass under the left superior vaginal wall, distal to the fornix and separate from the uterus and adnexa.
The patient underwent an uncomplicated, transvaginal cyst resection. The cyst was removed in its entirety and noted to contain sebaceous material and hair. See Figure 2. Vaginal packing was kept in place overnight, and the patient was discharged the next morning.
Patient represented to the ED two weeks later with complaints of vaginal bleeding and lightheadedness, soaking a pad every hour. She was taken to the OR and an approximately 5cm hematoma was evacuated from the site of cyst excision. A small bleeding vessel was suture-ligated and hemostasis was achieved. The vagina was packed and patient observed overnight. The patient was discharged the next day.
At a 2-week post-op visit, the vaginal incision was healed, pain was improved, and the patient was meeting post-operative milestones.

Comments: While vaginal dermoid cysts are rare, they should be considered in the differential. Especially when a cyst is seen in imaging and not identified laparoscopically, as was the case with this patient. This consideration can prevent unnecessary surgery and a prolonged treatment course.