Thyroid fine-needle aspiration biopsy: which lesions should be biopsied before 131I therapy?

INTRODUCTION: Suspicion of a neoplasm is one of the contraindications to radioiodine therapy in benign thyroid disease. The aim of this study was to present an optimal qualification scheme for fine-needle aspiration biopsy (FNAB) to rule out neoplastic lesions prior to radioiodine therapy. MATERIAL AND METHODS: 4207 patients with hyperthyroidism were referred for 131I therapy in 2000-2006. Prior to 131I therapy, all patients underwent thyroid function assessment, radioiodine uptake, scintigraphy, and ultrasound. Fine-needle aspiration biopsy with cytology was done in 578 (13.7%) patients. Therapeutic radioiodine was administered to 3564 (84.7%) patients. RESULTS: Malignancy was confirmed or suspected in 12 female patients (0.28% of all patients and 2.07% of patients who underwent FNAB). Prior to the study, cytology was done in only one patient. The diameter of the lesions was 6-28 mm. Cytology confirmed papillary carcinoma in 4 patients, follicular tumour in 6, and Hürthle's cell tumour in 1. There were indications for histopathology in one patient due to the presence of atypical cells. The primary diagnosis was toxic nodular goitre in 8 patients and Graves' disease in 4 patients. One of the patients with follicular tumour was referred for radioiodine therapy due to intolerance to thyrostatic drugs, elderly age, and comorbidities. CONCLUSIONS: 1. Thyroid scintigraphy prior to therapy is important for the choice of the site of FNAB. 2. Thyroid lesions in patients with nodular Graves' disease must be carefully investigated to exclude malignancy. 3. Preselection of patients for treatment of benign thyroid disease should be followed by cytology of the lesions at the Department of Nuclear Medicine.

The application of SPECT/CT scintigraphy with MIBI-Tc99(m) in the diagnosis of thyroid nodules - a preliminary report.

INTRODUCTION: Thyroid cancer diagnosis is based mainly on fine needle aspiration biopsy (FNAB) performed under ultrasonography guidance. Questions arise in cases of an inconclusive FNAB result - when there is no clear evidential data to support the existence of a malignant lesion or when there are any other reasons which make the decision process difficult, such as the patient's age or coexisting diseases. To clarify this issue the patient should be encouraged to undergo surgery treatment or to be followed up. Thyroid scintigraphy with an oncophilic tracer such as MIBI-Tc99(m) may be helpful. MATERIAL AND METHODS: The study comprised a group of 12 patients, aged 54-75 (av. 63.5) years, who, in 2009, underwent planar and SPECT/CT thyroid scintigraphy with MIBI-Tc99(m) using washout method. The tumour/background ratio in early and delayed images was calculated and the wash-out ratio was estimated. Patients with increased focal lesion uptake were operated on and the lesions were histopathologically verified. RESULTS: Abnormal scintigraphy results were obtained in 8 patients (10 lesions) and normal results in 4 patients (5 lesions). Out of 15 studies, in 13 cases the washout from the lesion was observed within 2 hours. It was noticed that the images obtained with SPECT/CT washout method were clearer and easier to read in comparison to planar studies. Three patients with an abnormal results underwent surgery and had benign histopathology results after the operation, in 3 patients the observation is being confirmed without any increase in malignancy suspicions, and 2 were lost for observation. CONCLUSIONS: Our preliminary results do support the use of MIBI-Tc99m in the evaluation of indeterminate thyroid nodules. To validate the hypothesis that MIBI-Tc99(m) may be used to exclude malignancy in lesions indeterminate by FNAB we propose to use SPECT-CT derived images and standardized evaluation criteria.

The occurrence of malignant thyroid lesions in patients after radioiodine treatment due to benign thyroid diseases.

INTRODUCTION: Radioiodine treatment (RT) of benign thyroid diseases is a well-known, safe, and effective treatment. In a group of patients after RT, who remained in long-term follow-up, sporadic cases of malignant thyroid lesions occurred. The aim of the study was to estimate how often it happened despite the exclusion of malignancy before RT. MATERIAL AND METHOD: A group of 4314 patients (7438 person-years) underwent RT and subsequently were followed-up for 1-8 years (mean 20.69 months). Apart from thyroid function estimation, if needed, fine needle aspiration biopsy (FNAB) of the thyroid or neck focal lesions was performed based on ultrasonographic or clinical examination. Patients with pathological FNAB were analyzed and histopathologically verified. RESULTS: In 12 out of 4314 cases (0.27%) suspicious FNAB results were found. Suspicious thyroid lesion results were found in 9 patients (8 F, 1 M), aged 46-73 (average 56 years) followed up for 3-57 months after RT: papillary cancer in two patients, Hürthle cell tumour in one patient, and suspicious cells in two patients (with benign lesions on postoperative histopathology). Two patients refused surgery (a suspicion of papillary cancer in one case and suspicious cells in FNAB in the second case). A follicular tumour in FNAB was suspected in two cases (no data about the first, and the second with lung cancer was not operable). In the remaining 3 cases FNAB revealed lymph node metastases due to other cancers. CONCLUSIONS: Malignant thyroid lesions in patients after RT due to benign thyroid diseases are seldom detected. However, periodical clinical and ultrasonographic evaluation is recommended.