Nevus and lentigo of the nail matrix
Nevus of the nail matrix
Nail matrix melanocytic acquired nevi are dermoscopically characterized by their brown background coloration and the regular pattern of the longitudinal micro-lines. Congenital nevi may exhibit atypical patterns and their differentiation from melanoma is very difficult on the basis of clinical and dermoscopical features. Therefore careful follow-up is mandatory.
Lentigo and lentiginoses of various types (e.g. Laugier–Hutziker, Peutz–Jeghers or Carney complex) may affect the nail unit. Examination of other involved areas and consideration that the nail pigmentation is polydactylic greatly aid in diagnosis. Dermoscopy shows a gray band-like pigmentation. Follow-up of these patients might be difficult since additional longitudinal pigmented bands may occur over time.
Blue nevus of the nail unit
Blue nevus of the nail unit is also a very rare entity. Dermoscopically, it corresponds to a blue proximal spot which is stable over time. In our view, the disease is rare enough to justify surgical exploration of the nail matrix and excision of the lesion.
- Ronger S, Touzet S, Ligeron C et al. (2002) Dermoscopic examination of nail pigmentation. Arch Dermatol 138(10): 1327–33
- Sendagorta E, Feito M, Ramírez P, Gonzalez-Beato M, Saida T, Pizarro A. (2010) Dermoscopic findings and histological correlation of the acral volar pigmented maculae in Laugier–Hunziker syndrome. J Dermatol 37(11): 980–4.
- Gencoglan G, Gerceker-Turk B, Kilinc-Karaarslan I, Akalin T, Ozdemir F. (2007) Dermoscopic findings in Laugier–Hunziker syndrome. Arch Dermatol 143(5): 631–3.
- Causeret AS, Skowron F, Viallard AM, Balme B, Thomas L. (2003) Subungual blue nevus. J Am Acad Dermatol 49(2): 310–12.