Fine needle aspiration biopsy-RT-PCR molecular analysis of thyroid nodules: a useful preoperative diagnostic tool

Fine needle aspiration biopsy (FNAB)-based cytology is an accurate preoperative diagnostic method for the evaluation of thyroid nodules. Despite its high specificity and sensitivity, the results are non-diagnostic in a significant number of cases, commonly due to inadequacy of the samples or the presence of undetermined cellular morphology. Overlap-ping cytologic features among follicular-derived lesions are the most common causes of cyto-histopathologic discordances. The management of thyroid nodules with a non-diagnostic FNAB remains controversial. The significant probability of malignancy imposes either the repeat of the procedure or direct surgery. Recent studies have demonstrated the important role of molecular-based techniques such as RT-PCR in the diagnosis of thyroid lesions. Follicular cells obtained from the remaining material within the needle can be used for RNA extraction and then for RT-PCR amplification of specific mRNAs that are expressed in benign or malignant thyroid nodules. Furthermore, FNAB-RT-PCR in combination with molecular scanning techniques or direct sequencing provides a valuable screening tool for mutations. The present review highlights the applications of FNAB-RT-PCR method in the identification of new diagnostic molecular markers. The parallel molecular and cytological analysis of FNABs may contribute to a more accurate diagnosis and, thus, to a more specific clinical management of thyroid nodules.