Background: Extranodal extension (ENE) is a documented negative prognostic factor in patients with papillary thyroid cancer (PTC). ENE is presumed to manifest in larger lymph nodes. Yet, to date, no study has proven this. This is a pilot study that specifically examines the size distribution of positive lymph nodes manifesting ENE in patients with PTC.
Methods: An Institutional Review Board approved review examined the size of all lymph nodes demonstrating ENE in postoperative PTC patients that underwent surgery for PTC under the care of a single surgeon between 2004 and 2014. All patients in the study had regional metastatic lymph nodes with ENE. Analysis of the size distribution for all lymph nodes with ENE was performed.
Results: A total of 47% of lymph nodes with ENE were ≤10 mm.
Conclusions: RESULTS indicate that clinically nonevident, small lymph nodes are at risk of harboring aggressive disease biology reflected in ENE. A total of 47% of all nodes fell within Randolph et al.'s classification of "small" lymph nodes, while 59% of the nodes with ENE were <1.5 cm-the threshold size that was deemed to be prognostically significant by Ito et al. It is apparent that clinically nonevident regional lymph nodes can have adverse histologic features and that the previous presumption that nodes with ENE only appear in clinically evident, macroscopic nodes is flawed.