www.icimagingsociety.org.uk
Ann D King, Department of imaging and interventional radiology, Chinese University of Hong Kong, Hong Kong
Nasopharyngeal carcinoma (NPC) is most commonly an undifferentiated carcinoma with a strong association with the Epstein Barr virus (EBV) and familial tendency. MRI is the modality of choice for NPC staging of the primary tumour and nodal metastases. The primary tumour spreads to the nasal cavity and infrequently to the oropharynx (T1); parapharyngeal space, medial and lateral pterygoid, and prevertebral muscles (T2); skull base, cervical vertebrae, pterygoid structures and paranasal sinuses (T3); intracranial structures, cranial nerves, orbit, parotid gland, beyond the lateral margin of the lateral pterygoid muscle, and hypopharynx (T4). NPC has a propensity to spread to nodes, the first echelon being nodes in the retropharyngeal region or upper internal jugular chain from where nodes spread in orderly fashion down the neck. Nodal staging differs from that squamous cell carcinoma in that bilateral nodes are down staged to NI when they are retropharyngeal, 6cm is the only criterion for size, and lower neck nodes are designated as N3. The first part of the lecture will focus on MRI staging of primary tumour and nodal metastases using a structured approach and report. The lecture will illustrate the staging process including assessment of the complex anatomy at the skull base, highlight areas important for NPC management, and review the changes in the latest 8th edition of the UICC/AJJC classification.
More recently MRI is also being used for the early detection of NPC. MRI has a high diagnostic accuracy of NPC detection, 10% of MRI detected NPCs are endoscopically occult, and MRI identifies slow growing tumours up to three years before they can be found endoscopically. In the second part of the lecture this new role of MRI for early detection of NPC in symptomatic patients and subjects in EBV population screening studies will be discussed.
References
1. Chong VF et al. Nasopharyngeal carcinoma with intracranial spread: CT and MR characteristics. JCAT. 1996;20:563-539
2. King AD et al. MRI of local disease in nasopharyngeal carcinoma: tumour extent vs tumour stage. Br J Radiol. 1999;72:734-741
3. Chong VF et al. Nasopharyngeal carcinoma. Eur J Radiol. 2008;66:437-447.
4. King AD, Bhatia KS. Magnetic resonance imaging staging of nasopharyngeal carcinoma in the head and neck. World Journal of Radiology. 2010;2:159-165
5. Ho FC et al. Patterns of regional lymph node metastasis of nasopharyngeal carcinoma: a meta-analysis of clinical evidence. BMC Cancer. 2012;12:98
6. King AD et al. Primary nasopharyngeal carcinoma: diagnostic accuracy of MR imaging versus that of endoscopy and endoscopic biopsy. Radiology. 2011;258:531-7
7. King AD et al. Detection of nasopharyngeal carcinoma by MR imaging: Diagnostic Accuracy of MRI compared with endoscopy and endoscopic biopsy based on long-term follow-up. AJNR 2015;36:2380-2385
2 июл 2024
