Magnetic Resonance Imaging of Retropharyngeal Lymphadenopathy in Nasopharyngeal Carcinoma

Received December 21, 2006; accepted February 1, 2007. OBJECTIVE The aim of our study was to document the patterns of RLN spread by using MRI. METHODS The MR images of 294 patients with newly diagnosed NPC were reviewed retrospectively. Criteria for metastatic lymph nodes included: shortest axial diameter, nodal necrosis, extracapsular spread, and a contrast enhancing rim. RESULTS RLN involvement was detected in 190 (64.6%) patients. A significantly higher incidence of metastatic RLNs was observed in patients with involvement of the oropharynx, nasal cavity, pre-styloid parapharyngeal space, post-styloid parapharyngeal space, levator muscle of the velum palatini, and tensor muscle of the velum palatine. Patients with level II, III, and V node involvement also had a higher incidence of metastatic RLNs. Of the 231 patients who had metastatic RLNs or cervical lymph nodes, 43 (18.6%) had only metastatic RLNs, 41 (17.7%) had only metastatic cervical lymph nodes, and 147 (63.6%) exhibited an involvement of both the RLNs and cervical lymph nodes. The difference between the incidence of RLN involvements (82.3%) and the incidence of cervical lymph node involvement (81.4%) was very small. CONCLUSION Metastatic RLNs are significantly associated with early stage primary tumor involvement and supper cervical lymph node metastasis in NPC.