Diagnostic evaluation of squamous cell carcinoma metastatic to cervical lymph nodes from an unknown head and neck primary site.

BACKGROUND: The purpose of this study was to evaluate the efficacy of the modern diagnostic evaluation for squamous cell carcinoma metastatic to cervical lymph nodes from an unknown head and neck primary site.

METHODS: One hundred thirty patients were evaluated between June 1983 and June 1997. All underwent head and neck examinations, head and neck computed tomography (CT), and/or magnetic resonance imaging (MRI) scans, panendoscopies, and biopsies of head and neck mucosal sites. Twenty-four patients underwent 2-[fluorine-18]-2-deoxy-D-glucose (FDG) single photon emission computed tomography (SPECT); 34 patients underwent tonsillectomy.

RESULTS: The primary site was identified in 56 patients (43%); the likelihood was increased in patients with suggestive findings on physical examination and/or radiographic evaluation. Eighty-three percent of the lesions were located in the tonsillar fossa and base of tongue. Results of FDG-SPECT scans were positive in 20 patients (83%); the primary tumor was detected in 7 patients (35%). Twelve (35%) of 34 patients who underwent tonsillectomy had a primary tumor discovered in the tonsillar fossa. Multivariate analysis of successful primary site detection revealed that suggestive findings on physical examination (p= .0225) and suggestive findings on CT and/or MRI (p = .0013) were significantly related to this end point.

CONCLUSION: The primary lesion will be detected in over 40% of patients with physical examination of the head and neck and CT and/or MRI followed by panendoscopy and biopsies. Limited data pertaining to FDG-SPECT suggest that this provides additional useful information in a small subset of patients. Tonsillectomy is useful for those with suggestive findings on physical examination and/or radiographic evaluation.