Development of multiple myeloma after 15 years of treatment for polycythemia vera and successful treatment using bortezomib: A case report.

Multiple myeloma (MM) and polycythemia vera (PV) rarely coexist; the clinical manifestations and treatment of this coexistence have not been described. An 81-year-old woman developed MM 15 years after undergoing PV treatment and was successfully treated using bortezomib. Herein, we share our experience of treating MM under such unusual conditions.