The approach to a patient with unexplained spontaneous bleeding uses a series of basic hemostasis principles to help pinpoint where the problem is. For example, a patient with mucocutaneous bleeding is initially suspected of having a defect in primary hemostasis, while another with soft tissue hematomas is likely to have a coagulation factor deficiency. Thus, understanding normal hemostasis and using common tests such as the platelet count, the prothrombin time and the partial thromboplastin time, will help determine the cause of the bleeding and the best therapy for most patients in a short period. Every once in a while, a patient presents with a less-than-classical scenario and poses a diagnostic and treatment challenge. In this session, the speakers will present three such cases and will discuss how they navigated through the possibilities in the differential diagnosis until the bleeding could be explained and stopped.