The clinical importance of axillary lymphadenopathy detected on screening mammography.

The aim of this study was to determine the incidence and cause of axillary lymphadenopathy detected by screening mammography and to devise a management protocol for this pathology. In a retrospective study of 95,806 consecutive screening mammograms, 37 cases of 'pathological' axillary nodes were identified using two or more of the following criteria: size > 2 cm, replacement of fatty hilum, rounded shape and generalized increased density. In 16 cases with an additional mammographic abnormality, 12 had a mass (10 malignant and two benign) and four had suspicious calcification (all malignant). In 12 of these cases, the lymph nodes showed malignancy (75%). In 21 patients with lymphadenopathy alone on screening, six patients had a known underlying diagnosis and were not recalled from screening. The remaining 15 patients were recalled for further assessment including fine needle aspiration cytology (FNAC). The ultimate diagnosis was benign in 10 cases (48%)--six reactive changes, one healed granulomatous disease, one rheumatoid arthritis, one amyloid and one acute infection--and malignant in 11 cases (52%)--six non-Hodgkin's lymphoma, four metastatic carcinoma and one leukaemia. In conclusion, there is a high incidence of malignant nodal involvement in cases of screen detected lymphadenopathy (62% of cases in our series). We would advise that patients with lymphadenopathy as the sole finding on screening mammography and in whom there is no known underlying cause should undergo FNAC followed by excision biopsy. Fifty per cent of such patients in this study had underlying malignancy.