An elderly male presents with 4x5 cm lump in right neck. FNAC revealed it to be squamous cell carcinoma. No primary was found. A diagnosis of unknown primary was made. According to AJCC system of classification, the TNM staging of the tumor w ould be:

Ref: Haas /, Hoffmann TK, Engers E Ganzer V. Diagnostic strategies in cen-ical carcinoma of an unknown primary (CUP). EurAnch Otorhinolaryngol 2002 Jul;259(6):325-33/NCCN guidelines 2014/AJCC 2010Explanation:CARC INOMA OF UNKNOWN PRIMARY (CUP) (TNM/AJCC 2010 STAGING)Stage Information for Metastatic Squamous Neck Cancer with Occult Primary.PRIMARY TUMORT0: Patients with unknown primary tumor.Tx: Patients whose tumor cannot be assessed or is not assessed.REGIONAL LYMPH NODESN0: No regional node metastasis.Nx: Regional nodes cannot be assessed.Nl: Single ipsilateral node, < 3 cm.N2a: Single ipsi lateral node. > 3 cm and <6 cmN2b: Multiple ipsilateral nodes. < 6 cm.N2c: Contralateral or bilateral nodes. < 6 cm.N3: Node > 6 cm.METASTASISM0: No distant metastasis.Ml: Distant metastasis.Mx: Unknown presence or absence of metastasis (could not be assessed).