Diagnosis of papillary and follicular thyroid cancers.

In general, thyroid cancer patients are usually presented with asymptomatic neck nodules. A differential diagnosis between malignant and benign thyroid disorder is very important for these patients. In the preoperative diagnosis, thyroid ultrasonography has been proven to be quite useful in the detection of thyroid lesions. There are two major reasons to perform thyroid ultrasonography before fine needle aspiration cytology (FNAC): to detect deep-seated small nodules, and to realize the nature of the clinically palpable nodules. Despite the limitations of aspiration cytology in the diagnosis of primary neoplasms, using this method can increase diagnostic accuracy to 92.89% in thyroid malignancy cases. Most thyroid malignancies can be diagnosed with FNAC, except for cases involving follicular thyroid cancer and Hürthle cell carcinoma. Although the serum thyroglobulin level has been used as a post-operative, well-differentiated thyroid cancer tumor marker, the assay cannot be used for preoperative diagnosis of thyroid carcinoma. Two dimensional gels electrophoresis has also been used as a diagnostic tool to elucidate tumor-specific proteins in the detection of well-differentiated thyroid cancers. The results of this technique need further investigation. In conclusion, and at the present time, FNAC is considered a useful tool in the pre-operative diagnosis of most thyroid cancers. For patients with follicular or Hürthle cell carcinomas, we need to develop further specific tumor markers for differentiating them between benign and malignant nodules.