PT - JOURNAL ARTICLE AU - Chandriya Chandran AU - Patamaporn Lekprasert AU - Corrado Minimo AU - Kay Win TI - Papillary thyroid carcinoma in struma ovarii: management after surgery AID - 10.1136/bcr-2022-252129 DP - 2022 Nov 01 TA - BMJ Case Reports PG - e252129 VI - 15 IP - 11 4099 - http://casereports.bmj.com/content/15/11/e252129.short 4100 - http://casereports.bmj.com/content/15/11/e252129.full SO - BMJ Case Reports2022 Nov 01; 15 AB - A woman in her 40s presented with a 3-month history of lower abdominal pain and intermenstrual bleeding. Ultrasound of the pelvis disclosed a 4 cm left adnexal mass. An MRI of the pelvis revealed a 2.2×3.6×2.4 cm solid, enhancing left ovarian mass. Due to high suspicion for malignancy, she underwent laparoscopic left salpingo-oophorectomy and resection of the tumour. Histopathology revealed papillary thyroid carcinoma in the background of struma ovarii as confirmed by thyroglobulin and thyroid transcription factor-1 positivity on immunohistochemistry. BRAF mutation analysis was negative. An ultrasound of the thyroid gland showed two low-risk nodules. An iodine-123 whole-body scan showed normal uptake in the thyroid gland. Thyroid-stimulating hormone (TSH) was 1.070 mcIU/mL (0.450–4.500), and thyroglobulin was 6.8 ng/mL (1.5–38.5). We risk-stratified this patient as low risk for recurrence. Risk stratification of malignant struma ovarii is essential to determine suitable thyroid targeting adjuvant therapy and reduce the risk of recurrence.