Unusual uptake of radioiodine in a retroperitoneal bronchogenic cyst in a patient with thyroid carcinoma.

The incidence of retroperitoneal bronchial cyst is rare and is unusual to be visualized on I scan. We report a 52-year-old man who received I therapy for papillary thyroid cancer. The postablation whole-body scan revealed increased radioiodine activity in the left abdomen. SPECT/CT localized this activity from a soft tissue mass in the retroperitoneal space. A retroperitoneal tumor was considered, and retroperitoneal laparoscopic tumor resection was performed. Pathologic examination confirmed a retroperitoneal bronchogenic cyst.