Three diffuse centroblastic lymphomas developed at the site of previous surgery. Two were preceded by atypical lymphoid infiltrates. Clinical data, microscopic features, and immunophenotypic studies were reviewed. All three patients presented with soft tissue masses at the site of previous surgery and metallic implants, with no evidence of lymphadenopathy, hepatosplenomegaly, or bone marrow involvement. There was no history of immunosuppression or risk factors. In two cases the initial diagnosis was of atypical lymphoid infiltrate progressing to lymphoma. Pathological examination showed a diffuse centroblastic lymphoma with an angiocentric pattern in one case. Phenotypic studies confirmed B cell origin. Soft tissue malignant lymphoma, though uncommon, can occur at the site of previous orthopaedic surgery, in particular joint replacement. Atypical lymphoid infiltrate may signal such an event.