—We were pleased to read the letter from Dr Miller and hear about his experience with the sclerosis of thyroid cysts. His reference to the book that he and his colleagues have written was appreciated. In reply to the first of the three caveats he mentions, we agree that it is possible that some cysts may recur after aspiration alone because of rebleeding from a small tissue remnant that is too small to resolve with conventional thyroid ultrasound. It is possible that small-field, high-resolution ultrasonography would identify such small lesions. However, we do not feel that rebleeding necessarily implies the presence of malignant neoplasm. The fact remains that only 1% to 2% of primary thyroid carcinomas are cystic,1 and only 1% to 2% of all purely cystic thyroid lesions contain a neoplastic component.1,2
The second caveat Miller mentions is the occurrence of a thyroid carcinoma in the wall