Detection of nodal micrometastases in head and neck cancer by serial sectioning and immunostaining.

We investigated the incidence of micrometastases from squamous cell carcinomas of the head and neck in neck dissection specimens originally staged as pNO. A total of 76 dissection specimens from 60 patients were evaluated using serial microscopic sectioning in 10-microns intervals, H & E staining, and immunostaining with an antibody to pan-cytokeratin. Examination of 1,020 lymph nodes from 76 neck dissection specimens revealed 8 micrometastases (7.9%) in 6 specimens from 6 patients with oral and pharyngeal primaries, resulting in upstaging. Six micrometastases were located in lymph nodes 3 to 6 mm in diameter. The surgeon should be aware of the relatively high incidence of micrometastases from oral and pharyngeal carcinomas, which are undetectable preoperatively or by routine histopathologic examination. Primary tumor site (oral cavity and pharynx) and certain features of the primary can delineate a group of patients with a higher risk of harboring occult metastases who may benefit from elective treatment of the neck.