Linfoadenopatias

Lymphadenopathy and Malignancy
ANDREW W. BAZEMORE, M.D., and DOUGLAS R. SMUCKER, M.D., M.P.H. University of Cincinnati College of Medicine, Cincinnati, Ohio The majority of patients presenting with peripheral lymphadenopathy have easily identifiable causes that are benign or self-limited. Among primary care patients presenting with lymphadenopathy, the prevalence of malignancy has been estimatedto be as low as 1.1 percent. The critical challenge for the primary care physician is to identify which cases are secondary to malignancies or other serious conditions. Key risk factors for malignancy include older age, firm, fixed nodal character, duration of greater than two weeks, and supraclavicular location. Knowledge of these risk factors is critical to determining the management ofunexplained lymphadenopathy. In addition, a complete exposure history, review of associated symptoms, and a thorough regional examination help determine whether lymphadenopathy is of benign or malignant origin. Unexplained lymphadenopathy without signs or symptoms of serious disease or malignancy can be observed for one month, after which specific testing or biopsy should be performed. While modernhematopathologic technologies have improved the diagnostic yields of fine-needle aspiration, excisional biopsy remains the initial diagnostic procedure of choice. The overall evaluation of lymphadenopathy, with a focus on findings suggestive of malignancy, as well as an approach to the patient with unexplained lymphadenopathy, will be reviewed. (Am Fam Physician 2002;66:2103-10. Copyright© 2002American Academy of Family Physicians.)

This article exemplifies the AAFP 2002 Annual Clinical Focus on cancer: prevention, detection, management, support, and survival.

ymphadenopathy, which is defined as an abnormality in the size or character of lymph nodes, is caused by the invasion or propagation of either inflammatory cells or neoplastic cells into the node. It results from a vast array ofdisease processes (Table 1),1 whose broad categories are easily recalled using the mnemonic acronym “MIAMI,” representing Malignancies, Infections, Autoimmune disorders, Miscellaneous and unusual conditions, and Iatrogenic causes. A common finding in the primary care outpatient setting, lymphadenopathy is typically explained by identifiable regional injury or infection. Among the serious illnessesthat can present with lymphadenopathy, perhaps the most concerning to the patient and physician alike is the possibility of underlying malignancy. The prevalence of malignancy is thought to be quite low among all patients with lymphadenopathy. Few studies define the prospective risk of malignancy with adenopathy, but three case series support the suggestion that the risk is very low. In twostudies,2,3 three of 238 and zero of 80 pa-

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tients presenting with unexplained lymphadenopathy were determined to have malignancies, while a third study4 retrospectively found a 1.1 percent prevalence of malignancy in primary care patients presenting to the office with unexplained lymphadenopathy. Essential to identifying the infrequent but serious causes of peripheral lymphadenopathy are thefollowing: an awareness of lymphatic anatomy, drainage patterns, and regional differential diagnosis; a thorough history including key factors such as age, location, duration, and patient exposures; and a focused physical examination according to the location of lymphadenopathy. Historical Clues
AGE AND DURATION

Lymphadenopathy lasting less than two weeks or more than one year with no progressivesize increase has a very low likelihood of being neoplastic.

The rate of malignant etiologies of lymphadenopathy is very low in childhood, but increases with age. Lymph nodes are palpable as early as the neonatal period, and a majority of healthy children have palpable cervical, inguinal, and axillary adenopathy.5 The vast majority of cases of lymphadenopathy in children is infectious or...