Primary non-Hodgkin lymphoma of the right femur and subsequent metastasis to the left femur: A case report and literature review.

Non-Hodgkin lymphoma of the bone is rare and typically causes an extensive bone lesion. The present study describes a case of diffuse large B-cell primary non-Hodgkin lymphoma of the bone, which occurred in the right femur, and was initially treated with surgery and chemotherapy. Following a 7-year period of complete remission, a new, similar lesion was identified in the left femur. With both lesions, there was no accompanying destruction of any other bones or organ involvement. Metastasis of PLB to the contralateral side is extremely rare and, to the best of our knowledge, this is the first report of this particular presentation in China or worldwide. We hypothesized that the present situation arose due to mechanisms involving the tumor microenvironment, circulating tumor cells, lymphocyte homing and self-seeding. The present report describes the case in detail, and discusses the possible underlying mechanisms and their potential contribution to the treatment of non-Hodgkin lymphoma, as well as the prevention of metastasis and recurrence, which may be of considerable clinical significance.