1. Histological evidence of squamous cell carcinoma of the head & neck (T1-T4 arising in either the oral cavity, larynx & pharynx, except Nasopharyngeal carcinoma);OR patients with histological evidence of squamous cell carcinoma metastatic to the neck and an unknown primary site after conventional workup without any of the following: i). Clinically suspected skin primary or previous diagnosis of skin cancer arising in the head and neck area; ii). Patients of Asian or African decent -possible nasopharynx primary; iii). Patients whose malignant adenopathy is confined to zone V -possible nasopharynx primary; and iv). Patients whose malignant adenopathy is confined to zone IV (supraclavicular)-possible lung primary.