CT scan to evaluate neck and primary

Treatment appropriate for primary with neck metastases

Confirm with biopsy of primary

Fine needle aspiration

FIGURE 2a. 1 Flowchart for workup of a suspicious neck node.

result in a high false-negative rate, tonsillectomy has been performed in the past. Several studies showed the benefit of tonsillectomy in. In a study by Randal et al. [16], 6 (18%) out of 34 patients with unknown primary were diagnosed as having primary tonsil carcinoma after having tonsillectomy. In a series of 87 patients with an unknown primary site, Lapeyre et al. [17] reported that subclinical disease had been found in the tonsil in 23 patients (26%).

Advances in molecular biology may be helpful in further identifying the primary site in these instances. Based on theories of tumor progression and field cancerization, Califano et al. [18] compared microsatellite analysis of tumors obtained in 18 patients with unknown squamous carcinoma cervical nodes with that of benign specimens obtained from directed biopsy. In 10 (55%) of the patients, at least one histopathologically benign mucosal specimen from defined anatomic sites demonstrated a pattern of genetic alterations identical to that present in cervical lymph node metastasis. These genetic changes include identical losses on multiple chromosomal arms or chromosomal breakpoints.

A chest radiograph needs to be obtained to rule out a pulmonary lesion or mediastinal adenopathy. A CT scan is obtained to evaluate the extent of neck disease, and the involvement of retropharyngeal nodes, as well as potential primary sites. It also provides information on the presence of necrosis and the involvement of extranodal tissues, soft tissue of the neck or the carotid sheath.

2[18F]-Fluoro-2-deoxy-D-glucose positron emission tomography (18-FDG-PET) imaging of tumor metabolism may also be useful in the search for the primary site. This scan is based on metabolic differences between malignant and normal tissues, such as a greater number of glucose transporters, molecular changes of the hexokinases, and a reduced number of glucose 6-phosphate, which leads to trapping of FDG-6-P04 in tumor cells. In a study by Jungehulsing et al. [19] of 27 patients with unknown primary carcinoma metastatic to cervical nodes, a primary tumor was identified in 7 patients and additional metastases were detected on 18-FDG-PET. If PET shows an uptake in a particular location, it can render further diagnostic approaches more specific in certain patients.

Therefore, if PET is going to be obtained as a part of routine workup, it is advisable to do so prior to panendoscopy so that any areas of suspicious uptake can be examined with biopsy during panendoscopy.

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