The role of fine-needle aspiration biopsy in the diagnosis and management of palpable masses.

Fine-needle aspiration (FNA) is a safe and economical biopsy technique that is widely applicable to palpable masses as a first-line procedure. However, successful FNA demands high specimen quality and experience on the part of both the aspirator and the pathologist. The best diagnostic yield is achieved by examining the aspirate on site with a microscope and making repeat passes if needed. Studies from several organ sites show generally high specificity for FNA in the diagnosis of cancer but slightly lower sensitivity. The accuracy and proper role of FNA vary among organ sites and different disease categories. FNA often makes a clear cut diagnosis but sometimes assumes more of a screening role. In cases of breast cancer, FNA can usually make a definitive diagnosis in the outpatient setting and greatly facilitate further management. Breast FNA reduces the need for open biopsies in women with benign aspirates, provided clinical and mammographic findings are also benign. Salivary gland FNA separates neoplasm from inflammatory lesions and reduces the need for surgery by as much as a third. Thyroid FNA greatly improves selection of patients for surgery and increases the percentage of cancers in nodules that are excised. However, follicular adenomas resemble carcinomas on FNA and must usually be excised. The accuracy and role of lymph node FNA is greatest with metastatic cancers. Its accuracy is somewhat lower in the primary diagnosis of lymphomas, which usually requires excision and histologic study for full characterization.