Papillary Microcarcinoma of the Thyroid

Kim, Jeong Han; Yang, Jung Hyun

Abstract

PURPOSE: According to the WHO, papillary microcarcinoma of the thyroid gland is defined as a tumor of 1.0 cm or less in diameter. Long-term follow-up of patients with papillary tumors of small size has shown that the prognosis is very good despite the tumors ability to metastasize to regional lymph nodes and distant sites, however the surgical management of these tumors remains unclear. The aim of this study was to analyze the clinical and pathologic features of papillary microcarcinomas and to determine an adequate extent of surgery for such cases.
METHODS
189 patients with papillary carcinoma of 1 cm or less in diameter underwent thyroidectomy at center between 1994 and 2001. Their medical records were retrospectively reviewed. A Chi-square test was used for statistical analysis.
RESULTS
One hundred eighty nine (26.3%) of the 720 papillary carcinomas were microcarcinomas and 44.4% of patients with these tumors presented with a palpable neck mass. 73.6% of these 189cases were diagnosed preoperatively as papillary carcinoma by FNAC and their mean size was 6.1 mm. Only 22 patients underwent lobectomy while the others experienced subtotal or total thyroidectomy with/ without modified radical neck dissection. Of the 5 recurred cases, 3 recurred in the contralateral lobe following lobectomy and 2 in cervical lymph node after subtotal or total thyroidectomy. Smaller tumors had a lower rate of extra- thyroidal extension although the same rate of lymph node metastasis as larger tumors.
CONCLUSION
The detection of papillary carcinoma by screening ultrasonography and the proportion of microcarcinoma seen in such cases is increasing. Greater than subtotal thyroidectomy may be more suitable for papillary microcarcinoma due to its multifocality and remnant recurrence.