Abstract
BACKGROUND: Synchronous or metachronous multiple primary malignancies (MPMs) are a known phenomenon. These occurrences may be spontaneous or related to environmental risk factors or genetic predisposition. Chronic myelogenous leukemia (CML) and Multiple myeloma (MM) are two uncommon hematologic malignancies, arises from two different cell lineage. The coexistence of CML and MM that is a rare phenomenon, with only 29 cases reported in the literature. To the best of our, this combination of triple primary cancers has not been reported in a single patient. CASE PRESENTATION: Herein, we reported a case of an 85-year-old Iranian male with three confirmed primary malignant neoplasms. The patient presented with synchronous prostate cancer and CML, in august 2016. He received imatinib and nilotinib for CML and hormonal therapy for prostate cancer. He remained in good control at further follow-ups for about 5 years. In the follow-up period and after 61 months treatment with tyrosine kinase inhibitors (TKIs), CML was undetectable in molecular tests, but the presence of serum M-protein, abnormal plasma cells in the bone marrow, and CRAB criteria was compatible with MM. CONCLUSION: We must evaluate the possibility of multiple primary cancers during cancer treatment and follow-up and it may be worthwhile to monitor serum electrophoresis and protein levels in TKIs-treated patients.