Kaposi's sarcoma (KS) is a malignant vascular neoplasm that typically appears opportunistically in patients with acquired immunodeficiency syndrome (AIDS); it can also arise in organ transplanted subjects and exceptionally in carriers of autoimmune diseases, such as Behçet's disease. A 23-year-old man with Behçet's disease who debuts with clinically and histologically compatible dermatosis with KS. Conclusions. KS is not exclusive to HIV-AIDS, it also prevails in situations of primary or secondary immunocompromision that favor its appearance, as is the case of Behçet's Disease and its immunomodulatory therapy.