text: The fundamental contribution of Jan C. Waldenström to the discovery and study of the so-called "Waldenström macroglobulinemia".
  Waldenström macroglobulinemia may be said to be characterized cheifly by two features: (1) a striking increase in IgM globulin of the "monoclonal gammapathy" type and (2) an abnormal bone marrow characterized by either a leukemic or leukemic-like picture, in which lymphocytes of various types are prominent. All the other features, hemorrhagic, hemolytic, rheologic (viscosity syndrome) must be considered as secondary manifestations. This historical review article summarizes the fundamental contribution of Jan Costa Waldenström to the discovery and study of this lymphoproliferative disorder.