Radioiodine (131I) accumulation in bronchogenic cyst in the setting of thyroid carcinoma remission

A 76-year-old woman had 131I accumulation within the mediastinum in the setting of thyroid carcinoma remission. Extensive diagnostic imaging including computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound, bronchoscopy, and subsequently a needle aspiration biopsy revealed that the mass was a bronchogenic cyst. Five-year clinical and laboratory follow-up showed that the patient was free from thyroid carcinoma recurrence.