I-131 False Positive Uptake In A Huge Parapelvic Renal Cyst

A male patient had undergone total thyroidectomy for thyroid papillary carcinoma. He was administered thyroablation activity of radioiodine. Whole body imaging after diagnostic activity of 131-I demonstrated intense radioiodine uptake in the right side of the upper abdominal region. The serum thyroglobulin level was low. Ultrasonography demonstrated a large irregular anechoic structure in the centre of the right kidney - a cyst in the parapelvic region. Renal cysts can lead to erroneous interpretation of radioiodine scintigraphy.