Thyroid function and incidentalomas in kidney transplant recipients

Ultrasound (US) is currently the best method for detecting thyroid nodules, especially those less than 1 cm in diameter, known as 'incidentaloma'. The ultimate diagnosis of non-palpable masses is done by fine-needle aspiration biopsy (FNAB), especially sonographically controlled (S-FNAB). Because of the increasing prevalence of thyroid nodules in Poland, it is essential to assess the nodules for FNAB and S-FNAB, especially in persons at high risk for thyroid carcinoma (patients after transplant with immunosuppression, persons with endemic goiter).

Prospective sonographic, color Doppler and power Doppler tests of the thyroid were performed in 44 kidney allograft recipients. The TSH level and urine iodide level was assessed in each patient. The control group included 35 healthy volunteers.

TSH levels were normal. The urine iodide concentration was over 30 mg/100 ml in 5 cases. In the rest of the group and in the controls it was below 30 mg/100 ml. In each case the thyroid was enlarged when compared to volunteers. There were thyroid nodules in 19 cases, single in 6 cases and multiple in 13. Of these nodules, 31 were smaller than 1 cm, 20 nodules were 1-2 cm in diameter, and none was greater than 2 cm. Nodules were classified according to whether or not there was flow within the nodule with eventual perinodular flow. FNAB revealed malignancies in 5 cases (nodules with flow).

Goiter was observed in all patients after thyroid transplant. In five of 44 cases malignancies were detected. In patients after transplant the US picture and the TSH and iodide levels should be checked.