Acute Polyarthritis as a Harbinger of Recurrent Non-Hodgkin Lymphoma

Background: Non-Hodgkin lymphoma (NHL) commonly presents with painless lymphadenopathy, splenomegaly, hepatomegaly, and constitutional symptoms of fever, night sweats, or weight loss. Skeletal involvement is possible, but it is rarely the first complaint. NHL may lead to a diagnostic dilemma when it presents solely with small joints involvement, mimicking Rheumatoid Arthritis. We present a patient with relapse of NHL manifesting as symmetrical polyarthritis. Case Presentation: A 69-year-old woman with prior history of NHL who achieved remission with chemotherapy presented to the Emergency Room (ER) three years later with progressively worsening pain in the small joints of both hands, associated with stiffness and swelling. She had associated fatigue and occasional night sweats but no fever, lymphadenopathy, skin rash, or oral ulcers. Physical examination revealed dactylitis of the right thumb and index finger; and synovitis of all the PIP, MCP, and metatarsophalangeal joints. She had multiple ER visits and failed treatments with steroids and opioids. She received presumptive diagnoses of Rheumatoid arthritis, acute gout, and carpal tunnel syndrome. Her inflammatory markers and autoimmune workup were unremarkable. Table 1 X-rays of her hands showed cystic changes; a Positron Emission Tomography (PET) scan revealed increased uptake in a periarticular and peripheral osseous distribution. Bone marrow biopsy did not reveal malignant cells, but histopathology of calcaneal bone confirmed infiltration by large B-cell Lymphoma. Due to her poor functional status, she was no longer a candidate for curative chemotherapy at the time of diagnosis, and she declined palliative radiotherapy or steroid. Conclusion: This case reflects the dilemma of physicians managing patients with seronegative symmetric polyarthritis. Physicians should always consider a broad list of differentials that include malignancy and promptly get a bone biopsy if destructive bone lesions are present on imaging because bone marrow biopsy can be unrevealing in NHL. Delayed diagnosis may lead to poor outcomes Keywords: Non-Hodgkin Lymphoma, polyarthritis, Rheumatoid arthritis Table 1: Laboratory results Test (Units) Result Reference range White blood cells (*10E3/uL) 4.8 4.8 – 10.8 Hemoglobin (g/dL) 13.3 12.0 – 16.0 Platelet (*10E3/UL) 176 130 - 400 Sodium (Meq/L) 139 136 - 145 Potassium (Meq/L) 3.6 3.5 – 5.1 Creatinine (mg/dL) 0.87 0.6 – 1.3 Blood Urea Nitrogen (mg/dL) 16 7 - 25 Calcium (mg/dL) 9.9 8.6 – 10.3 25 hydroxy Vitamin D (ng/mL) 44.7 \u3c20.0 Parathyroid hormone (pg/mL) 44 12 - 88 C-reactive protein (ng/dL) 0.32 \u3c1.00 Sedimentation rate (mm/hr) 35 0 - 20 Ferritin (ng/ml) 107 27 - 300 Rheumatoid factor (IU/mL) 14.0 Anti- cyclic citrullinated peptide (U/mL) \u3c0.5 \u3c3.0 Antinuclear antibody 1:40 Anti-double stranded DNA Negative Anti-smith antibody Negative Antineutrophil Cytoplasmic antibody (U/mL) \u3c0.3 Uric acid (mg/dL) 4.8 2.3 – 6.6 Lactate dehydrogenase (IU/L) 221 140 - 271 Lyme disease IgM antibody Negative Lyme disease IgG antibody Negative Parvovirus B19 IgG Antibody (IV) 4.53 Parvovirus B19 IgM Antibody (IV) 0.15 Ebstein-Barr Virus IgM antibody Negative Ebstein-Barr Virus IgM antibody Negativ