Case histories are presented of 2 patients in whom the occurrence of several signs indicated the presence of an immunocytoma. A 56 year-old man presented with marked splenomegaly and a lymphocytosis in peripheral blood picture. Lymphatic infiltrates were demonstrated in the bone marrow and liver. During the course of the disease the initial monoclonal gammopathy and the lymphocytosis disappeared. An extensive carcinoma of the stomach became clinically manifest one year later. In the second patient, a 74 year-old man, lymph node swelling, monoclonal gammopathy and bone-marrow cytology indicated lymphatic disease. There was no indication of carcinoma in spite of extensive investigations. The patients died three years later of a hypernephroma. Both patients demonstrated no sign of lymphatic disease at autopsy and, hence, a lymphatic reaction must be diagnosed retrospectively.