A Case Report of an Euthyroid Patient with Hyperfunctioning Thyroid Nodule

A thirty-two-year old female came to our clinic with a firm nodule at the anterior neck. It was 2×2cm in size, located in the right lobe of the thyroid gland and diagnosed as a thyroid nodule. The patient was considered as being in an euthyroid state according to the constitutional and laboratory findings. Radioiodine scintigraphic study revealed selective iodine uptake confined to the nodule and not to the rest of the gland. The study indicated that the hyperfunctioning thyroid nodule completely surpressed the activity of the thyroid gland, and yet the patient remained euthyroid. After exstirpation of the nodule, iodine uptake of the thyroid was restored to a normal level. The nodule was diagnosed as being a hyperfunctioning follicular adenoma of the thyroid. Since a functioning nodule like the one presented here is extremely rare in Japan, this case report should be informative for thyroid specialists.