Diagnosis of Adenomyosis at Iodine 131 Whole Body Scan

Aim: Total thyroidectomy and radioiodine (I-131) ablation are the initial treatment of differentiated thyroid cancer. Radioiodine has been used for ablation of normal remnant throid tissue and/or to treat metastatic lesions. Postablative I-131 whole body scan (RxWBS) is performed after administration of therapeutic/ablative dose of I-131. Diagnostic I-131 whole body scan (DxWBS) is performed for the follow-up of differentiated thyroid cancer. Case: A 49 year old woman with papillary thyroid cancer had total thyroidectomy followed by radioiodine ablation theraphy with 100 mCi of I-131. The RxWBS revealed uptake in the neck due to remnant thyroid tissue. Seven months later DxWBS performed following Thyrogen (R) (recombinant human thyroid stimulating hormone-thyrotropin alfa) stimulation. Whole body images showed persistant minimal remnant thyroid tissue in the neck. Additionally, there was an irregular I-131 uptake at the region compatible with uterus and gynecological assessment was suggested. After clinical examination and radiological evaluation (USG and MRI). Laparoscopy and uterine biopsy was performed and the final diagnosis was reported as adenomyosis. Conclusion: During the follow-up of differentiated thyroid cancer patients, RxWBS or DxWBS should be examined carefully; and maximum attention should be shown to unexpected I-131 uptake localizations.