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Dermatology Research and Practice
Volume 2012 (2012), Article ID 353864, 4 pages
Research Article

Tangential Biopsy Thickness versus Lesion Depth in Longitudinal Melanonychia: A Pilot Study

1Dermatologic Clinic, Hospital do Servidor Público Municipal de São Paulo, Rua Castro Alves 131, 01532-001 São Paulo, SP, Brazil
2Laboratório Paulista de Dermatologia Avenida Brigadeiro Luís Antônio 4315, Universidade Federal de São Paulo, 01401-002 São Paulo, SP, Brazil

Received 21 November 2011; Accepted 20 December 2011

Academic Editor: Eckart Haneke

Copyright © 2012 Nilton Di Chiacchio et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Longitudinal melanonychia can be caused by melanocyte activation (hypermelanosis) or proliferation (lentigo, nevus or melanoma). Histopathologic examination is mandatory for suspicious cases of melanomas. Tangential biopsy of the matrix is an elegant technique avoiding nail plate dystrophy, but it was unknown whether the depth of the sample obtained by this method is adequate for histopathologic diagnosis. Twenty-two patients with longitudinal melanonychia striata were submitted to tangential matrix biopsies described by Haneke. The tissue was stained with hematoxylin-eosin and the specimens were measured at 3 distinct points according to the total thickness: largest (A), intermediate (B) and narrowest (C) then divided into 4 groups according to the histopathologic diagnosis (G1: hypermelanosis; G2: lentigos; G3: nevus; G4: melanoma). The lesions were measured using the same method. The mean specimen/lesion thickness measure values for each group was: G1: 0,59/0,10 mm, G2: 0,67/0,08 mm, G3: 0,52/0,05 mm, G4: 0,58/0,10 mm. The general average thickness for all the specimens/lesions was 0,59/0,08 mm. We concluded that the tangential excision, for longitudinal melanonychia, provides an adequate material for histopathological diagnosis.