Lymphadenopathy: differential diagnosis and evaluation.

Although the finding of lymphadenopathy sometimes raises fears about serious illness, it is, in patients seen in primary care settings, usually a result of benign infectious causes. Most patients can be diagnosed on the basis of a careful history and physical examination. Localized adenopathy should prompt a search for an adjacent precipitating lesion and an examination of other nodal areas to rule out generalized lymphadenopathy. In general, lymph nodes greater than 1 cm in diameter are considered to be abnormal. Supraclavicular nodes are the most worrisome for malignancy. A three- to four-week period of observation is prudent in patients with localized nodes and a benign clinical picture. Generalized adenopathy should always prompt further clinical investigation. When a node biopsy is indicated, excisional biopsy of the most abnormal node will best enable the pathologist to determine a diagnosis.