Miscellaneous non-inflammatory musculoskeletal conditions. Pachydermoperiostosis

Pachydermoperiostosis (PDP), also known as primary hypertrophic osteoarthropathy, is a rare disease of the skin and bones that has clear genetic predisposition and well-defined clinical features. PDP is characterised by the presence of exuberant skin hypertrophy that, at the most distal parts of the extremities, takes a drumstick configuration. This deformity is conventionally known as digital clubbing. In advanced stages, skin hypertrophy may also be present in the head with furrowing of the facial features and eyelids ptosis. Another characteristic feature of the disease is periosteal proliferation of the long bones. Abnormal vascular endothelial growth factor and/or genetically determined prostaglandins overexpression may play a key role on its pathogenesis. No therapy has been shown to be effective in reversing hypertrophic changes. When bone pain is present, non-steroidal anti-inflammatory drugs are frequently useful. Isolated case reports have described that bisphosphonates may ease recalcitrant bone pain.