Value of Recombinant Human Thyrotropin in High-Dose Radioiodine Therapy: A Case Report

We report on a high-dose radioiodine therapy after injection of recombinant human thyrotropin (rhTSH) in a 61-y-old woman with compression of the spinal cord caused by metastasis of a follicular thyroid carcinoma. Fourteen years ago, the patient underwent subtotal thyroidectomy because of multinodular goiter without any histologic evidence for malignant disease, and the patient was put on thyroxine substitution (100 g/d). In April 2000, she developed paralysis of the right leg. Morphologic imaging revealed spinal compression caused by a space-occupying lesion within the thoracic spine. Subsequent biopsy and histology demonstrated metastasis of a follicular thyroid carcinoma. Therefore, high-dose radioiodine therapy was scheduled after 4 wk of hormone withdrawal. Within a few days of being off thyroxine, the patient’s paralytic symptoms worsened rapidly. The patient was again put on thyroxine, 100 g/d, and high-dose radioiodine therapy under stimulation with rhTSH was performed without any side effects. The second highdose radioiodine therapy 3 mo later, again performed under stimulation with rhTSH, showed significantly less iodine avidity, and thyroglobulin levels fell from 1,024 g/L to 361 g/L, thereby demonstrating therapeutic efficacy. Thus, rhTSH might be used as a tool not only in the diagnostic application but also in the therapeutic application of 131 I.