[Occurrence of malignant lesions in patients referred to 131I therapy due to benign thyroid diseases].

Introduction: (131)I therapy should be performed after exclusion of any morphological pathology that needs surgery--usually malignancy or its suspicion. The aim of the study was to evaluate the range of this problem in patients considered for radioiodine therapy due to benign thyroid diseases.

Material And Methods: In 2000-2005 year 3663 patients with hyperthyreosis were referred to (131)I therapy. All patients were subjected to routine procedure which comprised of thyroid function assessment, radioiodine uptake, thyroid scan, ultrasound examination. In 505 (13.8%) patients according to indications fine needle biopsy (FNAB) with cytological examination was performed. (131)I therapy dose was given to 3083 (84.2%) patients.

Results: Eight patients (1.6%) were positive or with suspicion of malignancy on FNAB. All but one had no cytological examination before referral. The diameter of the lesions ranged from 6 to 28 mm. Cytological diagnosis was: in 3 patients--ca papillare, in 3--follicular tumour, in 1--Hürthle'a cell tumour, and in one patient histopathological examination was required without definitive cytological diagnosis. In six patients primary diagnosis was toxic nodular goiter, in three patients Graves' disease.

Conclusion: 1. Obtained data underline the need for bigger malignancy alert of nuclear medicine physicians during qualification of patients for (131)I treatment despite of patients preselection by referring doctors. 2. Performing FNAB is a very important part of qualification to radioiodine treatment. 3. Thyroid scan is supportive in choosing a proper place for FNAB.