Skip metastases to lateral cervical lymph nodes in differentiated thyroid cancer: a systematic review

Papillary thyroid carcinoma is a slow-growing cancer with a generally good prognosis that sometimes have an aggressive behaviour. Metastases to neck lymph nodes is the first step of the diffusion. The central neck compartment is involved most commonly. The ipsilateral lateral neck compartments are usually involved afterwards, and the involvement of the contralateral one is considered a quite rare occurrence. In more rare cases, metastases to lateral neck compartment without central lymph node metastasis (so called "skip metastases") could be observed. Aim of this literature review study is to analyse the average incidence, pattern and risk factors of this occurrence.This study was performed according to PRISMA criteria. A final selection of 13 articles published in English language from 1997 to 2017 was performed. Any research article, review or meta-analysis was taken into consideration. Research was expanded considering the related references of articles.The incidence of skip metastases ranged from 1.6 to 21.8%. Risk factors such as age > 45 years, size < 5 mm and tumor located in the upper pole or isthmus of thyroid gland were found.Due to the frequency of skip metastases in thyroid cancer, a careful preoperative examination of lateral lymph nodes should be necessary.