Abstract
Renal involvement in large B-cell lymphoma represents an exceptional manifestation of non-Hodgkin lymphomas. Renal failure and bone metastasis by lymphomatous infiltration is extremely rare. We describe a 46-year-old woman presenting with a renal failure and a 5-month history of intermittent left knee pain that was previously misdiagnosed with osteoarthritis. It was due to a bilateral primary renal lymphoma (PRL) associated with bone metastasis. Knee MRI showed a permeative lesion and an abnormal signal in the metaphysis and diaphysis of the left proximal tibia with periosteal reaction and surrounding soft tissue swelling. The CT body scan showed a bilateral nephromegaly and multiple lytic bone lesion of aggressive appearance at the right iliac wing and right sacral ala evoking lymphomatous involvement. Node biopsy with immunohistochemistry study confirmed a diagnosis of large B-cell lymphoblastic lymphoma. In this article, we focus on clinical, radiological, immunohistochemical presentation, differential diagnosis and review the literature. Ten cases including our case were reported in our literature review of both renal and bone lymphoma. There was a male predominance, with a mean age of 55.1 years old. We noted a high frequency of renal failure in diagnosis. In X-rays, the metaphysis is the most common site of occurrence in long bones and the main sign was osteolytic bone destruction. The subtype of lymphoma was DLBCL stage IV in most cases except in one case where it was a hystiocytic lymphoma. Finally, prognosis was poor, more than half of patients died. PRL with bone metastasis is a rare malignancy that is difficult to diagnose. Clinicians should increase the awareness of the disease and consider a differential diagnosis of bone lesions. Early diagnosis and active treatment can improve patient prognosis.