Abstract
Antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE) are similar to be characterized by thromboembolic events and various clinical manifestations. We experienced a 21-year-old man with acute iliocaval deep vein thrombosis (DVT). Primary APS was initially diagnosed on the criteria, and after multidisciplinary treatment, iliocaval DVT was gradually regressed. Six months later, the patient complained of acute enteritis, followed by peripheral neuropathy and butterfly lupus. SLE was diagnosed, which suggested that the onset of SLE was preceded by APS. This case raises the question of a present consensus that these two diseases are clearly different clinical entities, although these are closely related.