Acro-osteolysis

Acro-osteolysis (plural: acro-osteolyses) refers to resorption of the distal phalanx. The terminal tuft is most commonly affected. It is associated with a heterogeneous group of pathological entities and, some of which can be remembered by using the mnemonic PINCH FO.

When there is linear bone resorption of the midshaft of the distal phalanx with a relatively spared terminal tuft, the condition is also referred to as band acro-osteolysis and carries a more limited differential diagnosis.

Pathology

Multiple digits

Terminal tuft resorption

• scleroderma ⁴
• Raynaud disease
• psoriatic arthritis
• thermal injury 
  • extreme cold: frostbite
  • extreme heat: burns, electricity
• trauma
• hyperparathyroidism
• epidermolysis bullosa
• porphyria
• drugs
  • phenytoin (occurs in infants of epileptic mothers treated with phenytoin) ⁷
  • ergot poisoning/abuse
• insensitivity to pain, e.g. leprosy, congenital insensitivity to pain
• juvenile chronic arthritis
• dermatomyositis
• vascular occlusion ⁵
• reactive arthritis ⁶
• pityriasis rubra pilaris (very rare skin condition) ⁸
• pachydermoperiostosis ⁹
• sarcoidosis ¹⁶

Midshaft resorption (band acro-osteolysis)

• polyvinyl chloride (PVC) exposure ¹⁰
• primary acro-osteolysis: Hajdu-Cheney syndrome
• hyperparathyroidism (also causes terminal tuft resorption)
• scleroderma ¹¹ (also causes terminal tuft resorption)
• idiopathic non-familial acro-osteolysis ¹⁵
• pyknodysostosis ^{13, 14} (also causes terminal tuft hypoplasia)
• biomechanical in guitar players ¹¹

Single digit 

• epidermal inclusion cyst ³
• glomus tumor of digit ³