66. Cystic Struma Ovarii Case Study in Adolescent Patient.

This case study is an investigation of a 13-year-old presenting with right lower quadrant abdominal pain and palpable abdominal mass who was diagnosed with cystic struma ovarii after a right salpingo-oophorectomy. The importance of this case stems from the rarity of this tumor, particularly the unusual presentation in adolescents and the limited consensus on postoperative management/follow up. The patient presented with one month of right lower quadrant abdominal pain that acutely worsened on the day of initial presentation. A pelvic ultrasound showed a complex multiseptated cystic structure in the right adnexal measuring 14.5 × 7.2 × 10.1 cm. She was evaluated by pediatric gynecology and was found to have a right adnexal mass that extended 4cm above the umbilicus. Tumor markers including CA-125, Inhibin, LDH, CA-19.9, CEA, and AFP, were obtained preoperatively, all were within normal range, and a plan was made to proceed with a diagnostic laparoscopy. Upon entry into the peritoneal cavity the cyst was noted to be abutting the anterior abdominal wall. The cyst was then drained of approximately 3.75L of dark brown stained fluid. Drainage of the cyst allowed for adequate visualization of the pelvis. There was no extracapsular disease noted. The origin of the cyst wall was traced to the right adnexa and a right salpingo-oophorectomy was performed as there was no distinguishable normal ovarian tissue visualized and the right fallopian tube was noted to be incorporated into the mass. The specimen was sent for frozen histology and returned as a serous cystadenoma and pelvic washings were without malignancy. The contralateral ovary was noted to be normal and there was no extracapsular spread noted. The final pathology resulted in cystic struma ovarii, after which, TSH, fT4, and T3 were obtained and noted to be within normal range. Our plan for follow up in this patient is repeat thyroid testing and a pelvic ultrasound in 6 months. This case uniquely provides several topics for consideration due to the rarity of this diagnosis. It represents only 0.5-1% of all ovarian tumors and is a diagnosis with only rare case reports in the adolescent population. First, there is no consensus on postoperative management. Determining surgical management between cystectomy versus unilateral vs bilateral oophorectomy is difficult given lack of criteria for diagnosing malignant struma ovarii in the absence of metastatic disease. Malignant transformation is present in 75% of tumors greater than 16cm. Finally, the lack of consensus on conservative versus radical surgical management, particularly in patients desiring future fertility, leads to difficulty in management of this condition. Supporting Figures or Tables https://www.abstractscorecard.com/uploads/Tasks/upload/19245/RGXGDRUQ-1380096-1-ANY(1).pdf https://www.abstractscorecard.com/uploads/Tasks/upload/19245/RGXGDRUQ-1380096-2-ANY.pdf [ABSTRACT FROM AUTHOR]