Clinical Characteristics of Papillary Thyroid Microcarcinoma / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Most papillary thyroid microcarcinoma (PTMC) carry a favorable prognosis, but a few patients present with aggressiveness. We classified PTMC according to the tumor size, and investigated the treatment, pathological finding and clinical behavior. SUBJECTS AND METHOD: Out of 714 patients submitted to surgical treatment for well differentiated thyroid cancer between 1996 and 2006, 179 (25%) patients had been identified as PTMC. These records were reviewed retrospectively, and followed up for 4 to 114 months (mean 43.3 months). RESULTS: The incidentaloma was 53 from 179 PTMC. The surgical procedures were hemithyroidectomy (n=79) or total thyroidectomy (n=100) including completion thyroidectomy. In the pathologic finding, 46 cases (25%) had extrathyroidal extensions and 37 cases (20%) had lymph node metastasis. In the total thyroidectomy cases, 35 cases had multiplicity, including 18 bilateral cases. When mass sizes were divided into those either bigger or smaller than 5 mm, statistical significance was found only in the extrathyroidal extensions (p=0.023). There were 2 recurrences in the total thyroidectomy cases and 4 in hemithyroidectomy, but without any statistical difference. With respect to size, there was only 1 recurrence in patients whose mass size was smaller than 5 mm and 5 in patients whose mass size was bigger than 5 mm; there was no statistical difference, however. CONCLUSION: Pathologically, extrathyroidal extension was more common in cases with tumor size more than 5 mm. This finding could be the evidence of poorer prognosis in these cases. However, there was no difference in the recurrence rate between the groups of different sizes and thyroidectomy methods. Therefore, surgical options should be carefully decided in the treatment of PTMC.