Diffuse soft tissue uptake of I-131 after post-thyroidectomy ablation therapy for thyroid cancer

I-131-induced cellulitis after I-131 ablation of a post-thyroidectomy remnant and metastatic differentiated thyroid cancer is rare. The authors describe a 45-year-old woman in whom painful neck swelling developed and diffuse soft tissue uptake of I-131 appeared after ablation therapy. She received 7.4 GBq (200 mCi) I-131 for papillary thyroid cancer. On the second hospital day, painful swelling of the neck and pharyngeal hyperemia developed. I-131 scintigraphy showed greatly increased uptake in metastatic lymph nodes with diffuse increased uptake in the soft tissues of the neck. The diffuse soft tissue uptake cleared as the painful swelling subsided.