Combined clinical, thyroid ultrasound and cytological features help to predict thyroid malignancy in follicular and Hϋrthle cell thyroid lesions: results from a series of 505 consecutive patients

Abstract

Summary: Objective The cytological patterns of follicular and Hϋrthle cell nodules are included among the indeterminate results of fine‐needle aspiration cytology, because distinction between benign and malignant lesion can only be made on histological criteria. The diagnostic value of atypia at cytology, clinical parameters and echographic patterns were examined to establish the risk of malignancy in 505 patients with follicular and Hϋrthle cell thyroid nodules at cytology. Design and patients The study included 505 consecutive patients who had undergone thyroidectomy from the period 2002–2005. Results Histological diagnosis of malignancy was carried out in 125 of 505 (25%) patients, the follicular variant of papillary carcinoma being the most frequent histotype. Only atypia at cytology (P < 0·0001) and spot microcalcifications at ultrasound (P = 0·009) were predictive of malignancy. Male gender, normal thyroid volume, single nodularity, nodule hypoechogenicity, size and blurred margins were associated with malignancy, although not significantly. An arbitrary clinical score allowed the identification of patients with high (41%, 110 patients) and low (16%, 242 patients) risk of malignancy. Combining the clinical score with the presence of atypia at cytology we could identify 30 patients (6%) in whom the risk of malignancy was as high as 63%. Conclusions Twenty‐five per cent of patients with a cytological result of follicular and Hϋrthle cell thyroid lesion had a final diagnosis of malignancy. Only atypia at cytology and spot microcalcifications at thyroid ultrasound were significantly associated with malignancy. Other clinical parameters and thyroid ultrasound patterns can be used to set up a clinical score useful for predicting the individual risk of malignancy before surgery.