Paget’s disease of bone and rheumatoid arthritis: a rare case of co-occurrence

The coexistence of Paget’s disease of bone (PDB) and rheumatoid arthritis (RA) is an uncommon clinical scenario, with limited cases reported in the literature. Both conditions independently affect bone metabolism – RA predominantly causes bone destruction, whereas PDB results in excessive and disorganized bone formation. This dual pathology complicates both diagnosis and management. We report the case of a 44-year-old female with seropositive RA who developed PDB, presenting with upper jaw swelling and elevated serum alkaline phosphatase levels. Histopathological examination revealed characteristic “jigsaw puzzle” trabeculae, confirming the diagnosis. Management required a multidisciplinary approach, including bisphosphonate therapy alongside continued disease-modifying antirheumatic drugs for RA, resulting in a favorable therapeutic response. This case highlights the importance of considering PDB as a differential diagnosis in RA patients with unexplained skeletal symptoms and underscores the need for early diagnosis and individualized treatment.