Fine-needle aspiration of the head and neck.

Fine-needle aspiration cytology is a valuable technique in the work-up of nodules and masses arising within the head and neck. Squamous cell carcinoma is present most often, and because of this relative frequency, the primary utility of needle-aspiration cytology is in the confirmation or exclusion of this diagnosis. FNA is particularly helpful in the work-up of cervical masses and nodules because biopsy of cervical adenopathy should be avoided unless all other diagnostic modalities have failed to establish a diagnosis. As such, needle-aspiration cytology represents an accurate, inexpensive, and rapid technique for elucidation of the etiology of cervical adenopathy. The majority of aspirates from cervical lymph nodes will disclose either reactive lymphadenopathy or metastatic squamous cell carcinoma. Occasional nodules will be due to lymphoma. While primary diagnosis of lymphoma by needle-aspiration cytology is generally not considered definitive, it is helpful in clarifying the nature of the process and the direction additional diagnostic tests should take. Similarly, establishing the presence of carotid body tumors, brachial cleft cysts or epidermal inclusion cysts excludes metastatic carcinoma and negates the need for open biopsy as well as allaying concerns on the part of both clinician and patient. Fine-needle aspiration of lesions within the mouth, oral pharynx, nasopharynx, and nasal sinuses has similar diagnostic goals, in that eliminating squamous cell carcinoma is its paramount objective. Fine-needle aspiration cytology can also establish a specific diagnosis for many lesions within this area. This technique can make specific diagnoses of angiofibroma, primary adenocarcinoma of the nasal sinuses, rhabdomyoma, granular cell tumor, and rhabdomyosarcoma. Each of these represents an important clinical entity with a specific therapy. Utilizing electron microscopy and immunohistochemical techniques, along with flow cytometry, can greatly broaden the diagnostic range and specificity of needle-aspiration cytology. Flow cytometry and immunohistochemistry are particularly useful in the establishment of monoclonality in lymphoproliferative processes and, hence, aid in the separation of reactive from lymphomatous lymphadenopathy. Immunohistochemistry can establish the precise nature of lesions as variable as rhabdomyosarcoma, olfactory neuroblastoma, and granular cell tumor. The prudent use of these techniques can be cost-effective and negate the need for more invasive diagnostic procedures. Needle-aspiration cytology represents a cost-effective and rapid technique for the assessment of nodules and masses within the head and neck area. Limitations in accuracy exist. In particular, the separation of reactive atypia in benign squamous epithelium from well-differentiated squamous cell carcinoma may be exceedingly difficult, if not impossible. Nonetheless, the technique has a high degree of accuracy for the diagnosis of both primary and metastatic disease.