title: Radioiodine accumulation in a large adnexal cystadenofibroma.
abstract: BACKGROUND
  Posttherapy or diagnostic whole-body radioiodine (131I) scans are conducted to observe metastases of differentiated thyroid carcinomas. Sometimes, false-positive scans occur due a variety of lesions. Here we report a patient with marked radioiodine accumulation in a large adnexal cystadenofibroma, a benign ovarian tumor.
  
  
  CONCLUSIONS
  A 51-year-old woman underwent subtotal thyroidectomy due to an enlarged-multinodular goiter that caused mild compression to trachea. In her preoperative neck ultrasonography, there were mixed cystic-solid nodules without suspicious ultrasound features that were smaller than 1 cm. Pathologic examination revealed multifocal papillary thyroid carcinoma. The residual thyroid tissue was ablated with 3.7 GBq radioiodine (131I) when the serum thyroglobulin concentration was 28.7 ng/mL and the serum thyroid-stimulating hormone level was 50 microIU/mL. A posttherapy whole-body scan on the 10th day after ablation revealed well-demarcated, circumscribed radioiodine uptake in the right pelvic region. Pelvic ultrasonography revealed a solid-cystic lesion with a diameter of 9 cm in the right pelvic region. Six months later, the lesion accumulated marked radioiodine in the whole-body scan (with 185 MBq 131I). The patient underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Pathologic examination revealed a benign cystadenofibroma without any coexisting thyroid tissue.
  
  
  CONCLUSIONS
  As far as we can ascertain, this is the first report of a radioiodine-accumulating cystadenofibroma. The mechanism for radioiodine accumulation in this patient's tumor is unclear.
authors.affiliation: Thyroidology Unit, Department of Nuclear Medicine, Akademi T.M., Izmir, Turkey. otturker@yahoo.com
authors.forename: Omer
authors.initials: O
authors.lastname: Turker
authors.forename: Ismail
authors.initials: I
authors.lastname: Dogan
authors.forename: Kamil
authors.initials: K
authors.lastname: Kumanlioglu
mesh_terms: D002291:Carcinoma, Papillary / Q000532:radiotherapy / Q000601:surgery; D003537:Cystadenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D005189:False Positive Reactions; D005260:Female; D006044:Goiter, Nodular / Q000601:surgery; D006801:Humans; D007044:Hysterectomy; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D010052:Ovariectomy; D011877:Radionuclide Imaging; D013964:Thyroid Neoplasms / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes