Endocrine Abstracts

Introduction: The prevalence of lymph node metastasis from micropapillary thyroid carcinoma (mPTC) in different studies is up to 33%. Preoperative diagnosis of central lymph node (CLN) metastasis is essential for the surgical management of those patients. Prophylactic CLN dissection for patients with mPTC is controversial. Our study aimed to assess the prevalence and the risk factors of LMN metastasis in patients mPTC

Methods: We retrospectively study the clinicopathological characteristics of 167 patients with PTC operated at the Second Department of Propaedeutic Surgery, University of Athens. Patients before surgery underwent ultrasound thyroid mapping for lymph node invasion assessment. All underwent total thyroidectomy with prophylactic central neck dissection.

Results: A total of 167 patients (73,1% females) were analyzed. The mean age was 51.08±13.38 years, and the mean follow-up was 5.3 years. In 30.2% (55/161) of the patients, the lesion was located in both thyroid lobes, in 29.1% (53/161) and 26.4% (48/161) in the right and left lobe, respectively. Only 2.7% (5/161) of the patients had lesions located in the isthmus. 33% (60/162) of PTC patients had bilateral lesions, and 41.8% (76/165) had more than one lesion. The median number of lesions was 1.0± 3.05. 54.5% (91/167) of the patients had macro-PTC. In 34.8% of them, the lesion was located in both thyroid lobes. 45.7% % had multiple lesions. Furthermore, 49.3% had capsule penetration, 39.1% had an extrathyroidal expansion, and 32.8% had lymph node invasion. 45.5% (76/167) had micro-PTC. In 41.8% of the patients, the lesion was located in both thyroid lobes. 48.1 % had multiple lesions. In addition, 47.3% of these patients had capsule penetration, 35.9% had an extrathyroidal expansion, and 30.8% had lymph node invasion.

Conclusion: Our study found an increased risk of lymph node invasion in patients with micro-PTC, compatible with macro-PTC. Thus, an ultrasound thyroid mapping for lymph node invasion assessment before surgery is needed.