Radiological differences in computed tomography findings and texture analysis between cystic lymph node metastases of human papillomavirus-positive oropharyngeal cancer and second branchial cysts

Introduction
The study aimed to analyse radiological differences in computed tomography (CT) findings and texture analysis between cystic lymph node metastases (CNM) in human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) and second branchial cleft cysts (2nd BC).

Material and methods
Patients with pathological evidence of CNM-HPV-OPC and 2nd BC, who underwent contrast-enhanced CT, were retrospectively evaluated. The evaluated characteristics include age, sex, and CT findings. CT findings included the maximum and minimum transverse diameters, maximum caudal diameter, thickness of the peripheral wall, presence of internal septation, presence of surrounding fat stranding, location, and 40 texture parameters.

Results
A total of 13 patients had CNM-HPV-OPC (19 lesions), while 20 patients had 2nd BC (20 lesions). Patients with 2nd BC were significantly younger than those with CNM-HPV-OPC (p < 0.001). In terms of diameter, 2nd BC lesions were significantly larger than the CNM-HPV-OPC lesions (p < 0.001). CNM-HPV OPC lesions had signifi­cantly thicker walls than 2nd BC lesions (p < 0.001). CNM-HPV-OPC lesions had significantly higher association with internal septations than 2nd BC lesions (p < 0.001). Second BC lesions were significantly less common at level III than CNM-HPV-OPC lesions (p = 0.047). Among the 40 texture parameters measured, 8 had significant differences (p ≤ 0.001).

Conclusions
There were significant differences in CT findings and textural parameters between CNM-HPV-OPC and 2nd BC lesions. These results may help in differentiating one from the other.