Incidental finding of ovarian teratoma on post-therapy scan for papillary thyroid cancer and impact of SPECT/CT imaging

Abstract

A 41-year old woman post thyroidectomy and neck dissection is presented in this case. She initially presented goiter and an enlarged cervical lymph node. She had no family history of cancer or radiation therapy. She had total thyroidectomy and found to have papillary thyroid cancer (T4N1M0). Histopathology report revealed multifocal classical papillary thyroid carcinoma with lympho-vascular invasion, extra-thyroidal extension, and positive lymph nodes. She was treated with 6.5 Gigabecquerel (GBq) of 131Iodine. Whole-body scan showed uptake in the neck and large focus in the left lower abdomen. Single-photon emission computed tomography SPECT/CT demonstrated a round shaped mass in the left pelvis. Pathology revealed cystic teratoma with benign thyroid tissue (struma ovarii), and no malignancy. Two months later, she had the second treatment with 5.5 GBq 131Iodine. Her follow-up stimulated and non-stimulated thyroglobulin levels were significantly lower, and there was no abnormal uptake in the follow-up scan.