Regarding neck node staging in head and neck cancer, an ipsilateral lymph node measuring 5.5 cm in greatest dimension without extranodal extension is classified as:

• A N2a
• B N2b
• C N2c
• D N3a ✓

Explanation

According to AJCC 8th edition, N3a is defined as a metastasis in a lymph node greater than 6 cm in greatest dimension without extranodal extension. N2a = single ipsilateral node 3–6 cm; N2b = multiple ipsilateral nodes each ≤6 cm; N2c = bilateral or contralateral nodes ≤6 cm. A node measuring 5.5 cm falls within the N2a category (single node 3–6 cm). However, N3a is >6 cm without ENE. At 5.5 cm, this is actually N2a — single ipsilateral 3–6 cm without extranodal extension.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.