A morphological study of ectopic plantar nail.

Ectopic nails are rare. Four adult patients presented to us, affected by true ectopic nails of the foot, sole, and toes, occurring bilaterally in one case. Full documentation of these anomalies was collected. The aim of this study was to better describe the morphologic features of ectopic plantar nails by using, besides histologic evaluation, transmission and scanning electron microscopy. New morphologic criteria were identified to determine if ectopic plantar nail differed from normal and ectopic hand nails. Morphologically, ectopic plantar nails are smaller than normal ones, but still form cuticles, nail grooves and nail folds, and periungual wrinkles. Furthermore, they form with a flat angle between the nail matrix and proximal nail fold, and have a nail plate interrupted by several transverse nails grooves.