Predicting the Unexpected: Clinicopathological Insights into Skip Metastasis in Papillary Thyroid Carcinoma

Background/Objectives: Papillary thyroid carcinoma (PTC) accounts for the majority of thyroid cancers, with lymph node metastasis, including skip metastasis (SM), playing a crucial role in guiding prognosis and therapeutic planning. SM, characterized by lateral lymph node spread in the absence of central compartment involvement, has been observed in PTC with a wide range of reported frequencies. The identification of risk factors for SM is crucial for preoperative evaluation and surgical planning. This research aims to explore the clinicopathological features and potential risk factors linked to SM in patients with PTC, while also offering valuable insights for preoperative risk evaluation. Methods: A retrospective cohort study was conducted on 81 PTC patients who underwent central and lateral cervical lymph node dissection (LND) in our center. Clinical, demographic, and pathological data, including age, sex, tumor size, location, subtype, extrathyroidal extension, lymphovascular invasion, and the number of lymph node metastases were analyzed. Clinicopathological characteristics were analyzed between SM-positive and SM-negative patient groups using suitable statistical methods. Additionally, a regression analysis was performed to identify the risk factors for SM. Results: Of the 81 patients, 17.3% (n = 14) were diagnosed with skip metastasis (SM). The SM-positive group had a significantly higher age (p = 0.006), smaller tumor size (p < 0.001), and higher rates of extrathyroidal extension (p = 0.006). The proportion of female patients was elevated in the SM-positive group, but this observation did not achieve statistical significance (p = 0.128). Tumors located in the upper pole were more common in the SM-positive group (p = 0.016). Multivariate analysis revealed that female sex, older age, and tumor location in the upper pole were significant risk factors for SM (p = 0.031, p = 0.004, and p = 0.017, respectively), while a lower number of lateral lymph node metastases was significantly associated with SM (p = 0.010). Additionally, an age over 43.5 years predicted SM with a sensitivity of 78.6% and a specificity of 72.7%. Conclusions: Skip metastasis is not uncommon in PTC and may be associated with older age, female sex, upper pole tumor location, and fewer lateral lymph node metastases. Recognizing these factors during preoperative assessment may aid in anticipating atypical lymphatic spread patterns and optimizing surgical strategies.