Persistent Elbow Pain And Swelling: A Diagnostic Dilemma

Title: Persistent Elbow Pain and Swelling: A Diagnostic Dilemma HISTORY: A 76-year-old female with a history of follicular lymphoma in remission since June 2023 presented with right elbow pain and swelling after an impact with a car door. Initial X-rays indicated a possible nondisplaced radial head fracture. She reported swelling and an extension block but no other symptoms. Ultrasound showed a large effusion; however, aspiration was unsuccessful with no fluid obtained. Due to persistent symptoms and inconclusive results, an MRI was ordered for further evaluation. PHYSICAL EXAM: GENERAL: no apparent distress. RESPIRATORY: Equal chest rise. CARDIOVASCULAR: Distal radial and pedal pulses are symmetric. SKIN: No obvious skin lesions. Elbow: INSPECTION: Notable effusion of the right elbow. PALPATION: TTP of the medial and lateral epicondyle. ROM: Extension block with 10 degrees of deficit; flexion block due to pain. NEUROVASCULAR: Distal radial pulse intact. STRENGTH: 5/5 in elbow flexion and extension DIFFERENTIAL DIAGNOSIS: 1. Radial head fracture 2. Elbow joint contracture 3. Intra-articular loose body 4. Osteoarthritis 5. Soft tissue tumor TEST AND RESULTS: PET Lymphoma Restage: Large intensely FDG avid mass involving the right humerus, extending from the elbow joint to the junction of the proximal and mid thirds of the diaphysis, consistent with active tumor. The lesion extends into the region of the elbow joint and appears related to cortical loss along the posterior right capitellum. Core Biopsy: Microscopic examination reveals many atypical lymphoid cells dissecting through skeletal muscle. A subset of the cells are large in size. CD21 immunostain highlights residual dendritic cell meshwork, indicating this likely represents a high-grade follicular lymphoma. Areas of diffuse large B-cell lymphoma are likely but appear focal. FINAL/WORKING DIAGNOSIS: Diffuse Large B-cell Lymphoma in the elbow TREATMENT AND OUTCOMES: The patient was referred to oncology for management, and a port was placed in the right internal jugular vein. She began a course of six rounds of R-CHOP therapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) and is currently experiencing symptomatic improvement with this treatment approach.