The role of fine-needle aspiration cytology in the management of thyroid disease.

Fine-needle aspiration cytology of the thyroid gland is a low-cost office procedure which even in children does not require regional anaesthesia. The method is safe, without appreciable complications or side effects. Since the needling is readily accepted by patients, it can be repeated when necessary. A morphological diagnosis is then rapidly obtainable, and time-consuming and expensive investigations are bypassed. In the hands of experienced cytopathologists, fine-needle biopsy is a reliable means of selecting patients for surgery, thereby reducing the frequency of operations for benign lesions. The cytological report enables the clinician to recognize the conditions which will benefit from non-surgical management, for example colloid goitre, thyroiditis and lymphoma, and also to plan surgical strategy in papillary, medullary and anaplastic giant cell neoplasms. In follicular neoplasms, aspiration biopsy cytology does not permit reliable distinction between adenoma and carcinoma. With combined consideration of aspiration biopsy cytology and scintiscans, however, it is possible to distinguish non-neoplastic from neoplastic follicular proliferation. In cases where cytological study does not give a specific or conclusive diagnosis, broad disease categories such as inflammatory or neoplastic states can be recognized. Even for these patients, therefore, the method can serve as a guide in the further management. In post-therapy follow-up of thyroid neoplasms, aspiration biopsy cytology permits rapid detection of recurrence.