Secondary lymphoedema of the upper limbs is a fairly frequent complication of breast cancer treatment. It is related to dissection of the axillary lymph nodes, and manifests itself in the form of clinically important lymphostasis, particularly when the dissection is combined with radiotherapy. Despite the fact that the surgical treatment of mammary cancer has become more conservative and, at the same time, radiotheraphy (when necessary) now proves less aggressive and more efficacious, secondary lymphoedema is still reported with incidence rates ranging from 5 to 25%, with an increase of up to 35% and more, when dissection of the axillary lymph nodes is followed by radiotherapy. The aim of this study was to highlight the essential importance of an early diagnosis of secondary lymphoedema, above all in relation to the prevention of this pathology. We report the case of a patient who, at the same time as the axillary lymphnode dissection, underwent a microsurgical operation consisting in the construction of lymphatic-venous shunts in the arm as a preventive measure, because lymphoscintigraphy of the upper limbs, carried out in advance, had revealed a predisposition to the development of lymphedema.