Unusual 131 I Uptake in the Right Sternocleidomastoid Muscle After Parathyroid Transplantation on 131 I Whole-Body Scintigraphy.

A 29-year-old woman with papillary thyroid cancer underwent thyroidectomy and parathyroid auto-transplantation. One month after surgery, the patient received radioiodine therapy. Two days after 131 I administration, localized 131 I uptake in the right sternocleidomastoid muscle was detected by post-therapy 131 I whole-body scintigraphy. We found that the 131 I uptake area was colocalized at the site of parathyroid transplantation.