AbstractBackgroundKaposi's sarcoma (KS) is a rare multifocal angiogenic tumor often seen in immunocompromised setting such as acquired immunodeficiency syndrome (AIDS) or organ transplantation recipients. Pemphigus vulgaris (PV) is a rare blistering disorder with mucocutaneous involvement for which immunosuppressive therapy has long been the core of treatment. Iatrogenic form of KS has been reported infrequently in pemphigus patients as a result of long‐term immunosuppressive therapy.CaseWe describe a 39‐year‐old male patient with confirmed diagnosis of PV who developed KS after receiving immunosuppressive agents for his pemphigus. KS was initially localized to the oral cavity with features mimicking exacerbation of his pemphigus.ConclusionThis interesting case of KS suggests that dermatologists visiting patients with pemphigus with discomfort in the oral cavity should have a high degree of awareness and consider other differential diagnoses along with merely an exacerbation of PV.