Unsuccessful radioiodine treatment of a non-toxic goiter: a case report

A middle-aged woman with a large right-sided, non-toxic goiter with low iodine uptake was admitted to the Department of Endocrinology with the purpose of volume reduction of the goiter. Thyroid pertechnetate scintigraphy showed homogenous and diffuse uptake in both lobes. Initially thyroxine treatment was given without volume-reducing effect. Radioiodine was administered twice to deliver a total radiation dose of 70 mCi iodine (I)-131. Subsequent pertechnetate scintigraphy showed that the normal-sized, normally functioning left lobe had disappeared after radioiodine, whereas the enlarged right lobe appeared unchanged. During the following years the size of the right lobe increased, and compression symptoms developed. The thyroid gland finally had to be removed by surgery. A large solitary thyroid nodule was removed, but no left lobe was identified. After surgery the patient had no thyroid tissue and had to be substituted by thyroid hormones. Despite good results of iodine treatment of non-toxic goiters, this case describes an unintended outcome leaving a patient without thyroid tissue, and a protracted course could have been avoided if the patient had undergone surgery earlier. However, this reported case should not discredit the use of radioiodine treatment of non-toxic goiters, but focus on patients with a single large solitary adenoma in whom this treatment may be inappropriate.