METASTATIC BREAST-CARCINOMA IN AXILLARY LYMPH-NODES - IN-VITRO US DETECTION

PURPOSE: To establish the ultrasonographic (US) characteristics of ben ign versus metastatic lymph nodes. MATERIALS AND METHODS: One hundred fifty-eight axillary lymph nodes in 40 patients (age range, 31-73 year s) surgically treated for breast cancer have been studied in vitro wit h a 7.5-MHz US probe in a water bath. The long-to-short axis ratio and the hilar and cortical characteristics were evaluated; the US finding s were correlated with the histopathologic findings. To estimate the l ong-to-short axis ratio, all lymph nodes were measured. RESULTS: Of th e 158 lymph nodes, 45 showed histopathologic evidence of metastasis; 3 8 of the 45 revealed US signs of malignancy. The signs that caused mal ignancy to be suspected were a long-to-short axis ratio of less than 1 .5, absence of a hilus, and disruption of the cortical zone. The most specific sign for the diagnosis of metastasis was absence of the hilus . The increase in the long-to-short axis ratio was the finding that ca used the most false-negative interpretations. Signs of malignancy were more accurate in lymph nodes 10 mm or larger than they were in lymph nodes smaller than 10 mm. CONCLUSION: Findings of in vitro US studies of axillary adenopathy provide the basis for the evaluation of lymph n ode metastasis in vivo before surgery, especially in those lymph nodes 10 mm or larger.