LBODP097 Malignant Struma Ovarii: Long Term Successful Treatment. Outcome

Abstract

Abstract 18 year old African American female saw her GYN in 9/2008 for abdominal pain. CT: bilateral adnexal masses (10×8 cm left; 6.3×3.1 cm right). Surgical pathology reported a left benign cystic teratoma and right corpus luteum cyst. Pain recurred in 2010. MRI showed: 9×7.5×4 cm right adnexal mass. Repeat surgery was done. Pathology: benign cystic teratoma with focal thyroid tissue - "Struma Ovarii". Abdominal pain recurred yet again in 2012. Sonography revealed a mixed solid/cystic pelvic mass measuring 10.6×7.9×7.6 cm. Exploratory laparotomy 9/2012 revealed a right adnexal mass and widespread peritoneal nodules. Pathology reported follicular tissue with colloid in the nodules - "Peritoneal Strumatosis" suggesting benignity. Upon further review was reclassified as metastatic well differentiated follicular thyroid cancer of ovarian origin with follicular thyroid tissue identified in peritoneal lymph nodes, spleen, bladder and rectal wall. The patient was then referred to endocrinology at our facility. On exam she was clinically euthyroid without thyromegaly or nodularity. Thyroid hormone levels were normal. Antithyroid antibodies were absent. Serum Thyroglobulin (Tg): elevated (229; normal 2-35 ng/ml) as was CA125 (64; normal <21 U/ml). Immunohistochemistry: positive for Tg and Thyroid transcription factor-1. Molecular markers: no mutations in BRAF, RAS, or TP53. In preparation for radioactive iodine (RAI) therapy, total thyroidectomy was performed 4/13/2013 and reported as normal thyroid tissue. Dosimetry findings: very iodine avid tissue with prolonged retention (33% at 6 days). Maximum tolerated dose: 200 mCi. A 62.8 mCi RAI was administered 7/13/2013. Post RAI whole body scan (WBS): numerous focal areas of increased uptake in abdomen and pelvis consistent with metastatic disease. Treatment with L-thyroxine was given to suppress TSH. Follow up WBS 12/26/2013 showed persistent increased uptake in abdomen and pelvis. Serum Tg was high (198. 0). A second RAI dose of 104.8 mCi was given. Post RAI WBS confirmed multiple areas of metastatic disease in abdomen and pelvis. Subsequent serum Tg levels down trended. WBS 11/12/2014: only two residual abnormal foci in the lower neck and one inferior to the liver without abdominal or pelvic foci. Given the dosimetry issue and the reassuring serum Tg levels, surveillance was continued. WBS 9/25/2015: unchanged. Now age 27, WBS 1/26/2022: only residual faint lower neck uptake, resolution of the focus inferior to the liver and no distant foci. Stimulated Tg was normal at 2.2 ng/ml with stimulated TSH >110. 0 uIU/ml. Presentation: No date and time listed