A Clinical Case of a 74-Year-Old Patient with Overlap of Rheumatoid Arthritis and Axial Spondyloarthritis

In the past, rheumatoid arthritis and axial spondyloarthritis were considered mutually exclusive diseases because of their distinct genetic and clinical profiles. We present the case of a 74-year-old man with seropositive rheumatoid arthritis and long-standing axial spondyloarthritis, illustrating the diagnostic and therapeutic challenges associated with this rare overlap. The patient presented with symmetrical erosive-destructive polyarthritis involving joints of the upper extremities, strongly positive immunological markers, a history of chronic inflammatory low back pain beginning at approximately 35 years of age, positive HLA-B27, radiographic sacroiliitis and spondylitis with syndesmophyte formation and complete bony bridges between vertebral bodies. Given the predominant clinical manifestations, the presence of concomitant prostate carcinoma, and having in mind the urological consultation, combination therapy with methotrexate and tocilizumab was initiated, resulting in low disease activity. This case highlights the challenges in diagnosing and treating patients with two distinct inflammatory joint diseases and discusses the importance of individualized therapeutic strategies.