From Juvenile Idiopathic Arthritis to Pachydermoperiostosis: A Journey to an Unexpected Rare Diagnosis.

Pachydermoperiostosis, also known as primary hypertrophic osteoarthropathy or Touraine-Solente-Golé syndrome, is a rare genetic disorder that represents a small fraction of hypertrophic osteoarthropathy cases. It typically begins during adolescence, affects males more frequently and follows either an autosomal dominant or recessive inheritance pattern. The disease is characterized by the triad of pachydermia, periostosis and digital clubbing, often accompanied by hyperhidrosis, seborrhea, cutis verticis gyrata and joint effusions. Although articular involvement is usually non-erosive, the disorder may mimic inflammatory arthritis and lead to diagnostic delays. Recognition of the major and minor diagnostic criteria is crucial to distinguish PDP from secondary forms related to pulmonary, cardiac or neoplastic disease.