Various Clinical Scenarios in Secondary Malignant Lymphedema

Diagnosing malignant lymphedema is a challenge in daily clinical practice. Clinically, patients may show clear signs of malignancy, but this is not always the case, and at times the diagnosis is not straightforward. In some patients, pain, hardness of the tissues, joint stiffness, proximal involvement, collateral circulation, or an acute onset will provide the clue to determining malignancy. Our aim is to describe several diverse scenarios of Secondary Malignant Lymphedema (SML) with the etiopathogenesis. One possible cause is lymphatic obstruction due to extrinsic compression of lymphatic vessels and/or nodes by either the primary tumor or metastatic masses. Lymphatic obstruction can also be caused by tumoral infiltration. This infiltration can affect both deep and regional nodes as well as cutaneous and subcutaneous vessels and is commonly known as lymphangitis carcinomatosa. Malignant lymphedema can also be secondary to obstruction of the venous flow due to tumoral venous thromboembolism or to extrinsic compression of the veins by tumors or adenopathic masses. Nevertheless, the most frequent cause of this illness is a mixed mechanism of compression of the lymphatic and venous systems. Frequently, SML is the first manifestation of relapse. When lymphedema appears abruptly, is progressive, with intense pain, associated with collateral circulation, or with hard and infiltrated skin or joint stiffness, SML must be ruled out with an urgent referral to the oncologist and an imaging evaluation.