Gonadal damage due to radioactive iodine (I131) treatment for thyroid carcinoma.

Papillary carcinoma of the thyroid is the most common type of thyroid cancer and is associated with a good prognosis. Complications of treatment with surgery and radioiodine are uncommon. We report the case of a 13 year old boy who developed testicular damage following treatment with radioactive iodine 350 mCi for a papillary carcinoma of the thyroid. Four years after radioiodine treatment there has been no suggestion of recovery of spermatogenesis. Detailed follow-up studies of similarly treated young patients are required to define the incidence of this complication and to determine its reversibility.