Acro-osteolysis due to protein S deficiency: A rare case.

Protein S deficiency is a hypercoagulable state due to deficiency or dysfunction of protein S resulting in an abnormally regulated clotting cascade. Anti-phospholipid antibodies (APLA) may cause protein deficiency. Most of the cases reported in the literature are associated with venous thromboembolic events. Arterial thrombosis leading to gangrene due to underlying protein S deficiency is relatively rare. We report the uncommon and first-ever case of osteolysis of the great toes in a young male, nonsmoker, APLA negative, and protein S deficient.