[Myeloproliferative masks of multiple myeloma: A review of literature and clinical case reports].

Concurrences of multiple myeloma with myeloproliferative diseases or secondary myeloid leukemoid reactions are rather rare. The paper describes 3 cases of multiple myeloma: the first case concurrent with neutrophilic leukocytosis; the second case with secondary erythropoetin-dependent erythrocytosis, and the third case with chronic myeloid leukemia. In such cases, an accurate diagnosis requires molecular testing, besides routine clinical and laboratory studies. The paper discusses therapeutic strategy in cases of a concurrence of 2 competing tumors of the blood system: to treat them simultaneously or the most aggressive tumor now, as well as a relationship between multiple myeloma and chronic myeloid leukemia, other myeloproliferative disorders, and secondary myeloid leukemoid reactions.