Primary bone lymphoma (PBL) is rare disease that originates from the medullary cavity. The case is reported of a 74 year-old woman with a clinical picture characterised by B-symptoms and pathological fracture of both tibias. Nuclear magnetic resonance found a hypointense heterogeneous infiltration in both proximal tibia with high uptake by a soft tissue tumour with predominance in the left leg. The biopsy showed diffuse large B-cell lymphoma. The patient was diagnosed with a multifocal primary bone lymphoma. To our knowledge, it is the first case reported in Peru.