Iso-Kikuchi syndrome with absence of ring fingers and metacarpal bone abnormality

[3] The five criteria characterizing COIF include the following: (i) congenital occurrence; (ii) unilateral or bilateral index finger involvement; (iii) variability in nail appearance; (iv) possible familial involvement; and (v) frequently associated bone abnormalities. In utero, ischemia of the palmar digital artery and a dysplastic change in the crescent-shaped cap of the distal phalanx are the two main candidate pathogenetic mechanisms that have been proposed.