Clinical Characteristics of Thyroid Micropapillary Carcinoma

Lee, Sang Hyuk; Jin, Sung Min; Rho, Young Soo; Kim, Jin Hwan; Lee, Seung Suk; Choi, Hyun Jin

Abstract

BACKGROUND AND OBJECTIVES: Papillary microcarcinoma of the thyroid gland (PMC) is defined as a papillary thyroid cancer (PTC) measuring less than 1 cm in its diameter. PMC is frequently diagnosed today, mainly as a result of the wide use of neck ultrasonography and fine needle aspiration biopsy. Despite the overall excellent prognosis for patients with PMC, the extent of thyroid resection and the necessity of lymph node dissection have become the issues of controversy. The rising incidence of the PMC among PTC necessitates the identification of prognostic factors and standardization of treatment protocols. Therefore, to evaluate the characteristics of PMC, we reviewed our experiences.
SUBJECTS AND METHOD
Between 2000 and 2005, 265 patients underwent thyroid surgery and 194 patients showed PTC. Of these patients, 53 patients (27.3%) had PMC (9 male, 44 female, mean age 50.1 years). The data from these patients were retrospectively analyzed.
RESULTS
The mean tumor size was 7.19 mm. The most frequently presenting symptom was thyroid mass only (77%) and the combined thyroid diseases were found in 35 patients (66%). Twelve patients (27.9%) had multifocal microcarcinomas and in 11 patients (20.8%) had extrathyroidal invasion. Lymph node metastasis was found in 18 patients (33.9%). Lymph node metastasis was significantly associated with the presence of extrathyroidal invasion (p=0.031), lymph node metastasis (p=0.008) and extrathyroidal invasion are more frequently observed in PMCs over 5 mm in size.
CONCLUSION
These clinical characteristics may be considered as prognostic factors of the PMC. So the treatment modalities should be chosen taking into consideration of the various clinical factors.