Non-Hodgkin’s Lymphoma of the synovium discovered in total knee arthroplasty: a case report

We present a case in which non-Hodgkin’s lymphoma was found coincidentally in the synovium during knee joint replacement surgery in a 69-year old woman with rheumatoid arthritis. Pigmented, vitreous tissue was resected, which turned out to be a diffuse large B-cell lymphoma after histological examination. The coincidental intraoperative finding of intra-articular non-Hodgkin’s lymphoma was reported twice before, presenting as synovial proliferation in elbow and shoulder surgery. In a few other cases non-Hodgkin’s lymphoma presented most often in the knee, as a bone lesion or, when soft tissue was involved, as arthritis.Non-Hodgkin’s lymphoma should be considered in patients with autoimmune rheumatic diseases. In case of persistent arthritis, non-respondent to anti-inflammatory drugs, a biopsy might be warranted. Moreover, when arthroscopy or arthrotomy is planned, any atypical tissue should be sent for histological analysis. Early diagnosis of NHL can contribute to improved outcome of its rapidly developing treatment options.Non-Hodgkin’s Lymphoma (NHL) is a malignancy of the lymphatic system of uncontrolled proliferation of B- or T-lymphocytes. The musculoskeletal system is affected in 5-25% of the patients [1-4]. Musculoskeletal involvement of NHL has been reported before as a primary bone lesion or as intra-articular soft tissue proliferation with arthritis as presenting symptom. We present a case in which atypical soft tissue found during a routine knee arthroplasty led to the diagnosis systemic NHL.A 69-year old woman was referred to our clinic with chronic left knee pain. Her walking distance was limited and she complained of joint stiffness.After a sports trauma 40 years ago, the patient underwent a lateral meniscectomy of the left knee. Two loose tissue parts were removed; histological analysis showed synovial tissue with chronic inflammation possibly indicating rheumatoid arthritis (RA). The following decades she had internal and rheumatological examination