[Osteoarthropathy]

Paraneoplastic osteoarthropathy includes various forms of arthritis syndrome which probably relates to immune mechanisms, and much more often hypertrophic osteoarthropathy(HOA). HOA is often accompanied with primary lung cancer, malignant pleural mesothelioma, chronic pulmonary diseases, cyanotic congenital heart diseases, among others. The presentation of HOA sometimes precedes the diagnosis of underlining malignancies, and consists of finger clubbing, polyarthralgia, and pain and swelling of forearms and lower thighs. Acute onset of the symptoms except for finger clubbing may indicate expansive growth of malignant diseases. Recently, a gene responsible for prostaglandin E2 degradation was identified as a cause of idiopathic HOA. As idiopathic HOA is clinically indistinguishable from paraneoplastic HOA, this discovery may highlight some common biomarkers involved in tumor progression and HOA formation.