Papillary thyroid microcarcinoma: a surgical perspective.
Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid cancer measuring less than 10mm in its greatest diameter. It is the most common form of thyroid cancer, detected in up to 36% in autopsy studies. The wide availability and use of neck ultrasonography in the evaluation of carotid arteries and of the thyroid resulted in an increased detection of PTMC. PTMC is often multifocal. The diagnosis is usually based on a combination of clinical examination, laboratory investigations, and specialized radiological techniques (mainly neck ultrasonography combined with fine-needle aspiration cytology). A common scenario is the diagnosis of PTMC as an incidental finding following thyroidectomy for a presumably benign thyroid disease. Despite some controversy, most authors agree that PTMC should be treated by total or near-total thyroidectomy, provided it can be performed safely. Because of its many and major advantages, in our clinical practice, total or near-total thyroidectomy is the procedure of choice for the management of PTMC. Given the high incidence of PTMC as an incidental finding and the frequent multi-focality, we also favor total or near-total thyroidectomy for the surgical management of nodular thyroid disease (multinodular goiter or dominant presumably benign thyroid nodule/s). Despite some controversy, we perform central neck lymph node dissection electively, in the presence of cervical lymphadenopathy. Radioiodine ablation therapy may be used as an adjuvant therapy. Prognostic factors (such as tumor multicentricity, positive lymph nodes, capsular or vascular invasion) or scoring systems (such as the AMES) can be used to select patients for radioiodine adjuvant therapy. Suppression therapy is needed after surgical management. Despite the potential for neck lymph node and even distant metastases, the biological behavior of PTMC is in general benign and the prognosis is very good.