Three-dimensional melanin distribution of acral melanocytic nevi is reflected in dermoscopy features: analysis of the parallel pattern

Dermatology. 2008;216(3):205-12. doi: 10.1159/000112927. Epub 2008 Jan 9.


Background: Acral melanocytic nevi have parallel patterns on dermoscopy; however, it is not understood why pigment distributions exhibit such patterns.

Aim: To clarify the reason why melanin distributions in acral melanocytic nevi exhibit a parallel pattern on dermoscopy.

Methods: A serial sectioning perpendicular to the skin markings was performed, and each section was stained with modified Fontana-Masson staining to pick out melanin granules. These sections were then reconstructed to three-dimensional images by an image processing software, and these three-dimensional images were analyzed.

Results: Melanin columns in the cornified layer were mainly seen in the dermoscopic images of acral melanocytic nevi. In the parallel-furrow pattern melanin columns were arranged vertically, and in the fibrillar pattern they were arranged in a slanting fashion.

Conclusion: Melanin columns in the cornified layer, not melanin in the basal layer, mainly contribute to the dermoscopic pattern of acral melanocytic nevi.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dermoscopy*
  • Foot Diseases / pathology*
  • Hand / pathology*
  • Humans
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional / methods*
  • Melanins / analysis*
  • Melanins / metabolism
  • Nevus, Pigmented / pathology*
  • Silver Nitrate
  • Skin / metabolism
  • Skin / pathology
  • Skin Neoplasms / pathology*


  • Fontana-Masson stain
  • Melanins
  • Silver Nitrate