Pachydermoperiostosis is a rare developmental defect, first described by Friedreich in 1868 and recognized later in 1935 by Touraine, Solente and Golé as a familial disorder with three forms: complete (periostosis and pachydermia), incomplete (without pachydermia) and the forme fruste (pachydermia with minimal skeletal changes). It is inherited in an autosomal dominant fashion with variable expressivity and penetrance; autosomal recessive forms have also been reported. It is characterized by digital clubbing, cylindrical thickening of the legs and forearms, hyperhydrosis, sebaceous gland over activity and symmetrical irregular periosteal ossification predominantly affecting the distal ends of long bones. The syndrome is associated with thickening and furrowing of the facial features, deep nasolabial folds, a corrugated scalp, and often greasy skin of the face and the scalp.
Pachydermoperiostosis usually begins soon after puberty, progresses for five to ten years, and remains unchanged throughout life. The syndrome has a pronounced predilection for males, with a male to female ratio of 7:1.