Mondor’s disease (MD) is a rare condition, which is considered a thrombophlebitis of the subcutaneous veins. It commonly occurs on the anterolateral thoracoabdominal wall, but it can also occur on the penis, groin, antecubital fossa and posterior cervical region. The clinical features are a sudden and typically asymptomatic onset of a cord-like induration, although some patients report a feeling of ‘strain’. It is a self-limiting process that lasts a short period of time, which may be the reason why there are few reports about its diagnosis and treatment. Its pathogenesis has remained unclear, because of the lack of methods to reliably differentiate between veins and lymphatic vessels. Immunohistochemical staining for CD31 and D240 has been identified recently as the best method to distinguish small veins from lymphatic vessels, making it a valuable technique in diagnosing not only MD, but also many other diseases in which veins or lymphatic vessels are affected. MD has been associated with several systemic diseases such as breast cancer and hypercoagulability states, thus laboratory studies are recommended to exclude any possible systemic disorders. As this condition is usually a benign and self-limiting process, vigorous treatment is only recommended when the process is symptomatic or recurrent.