Consensus on melanonychia nail plate dermoscopy* * Paper produced by the International Study Group Meeting on Melanonychia (2010) - Miami, USA.

Consenso sobre dermatoscopia da placa ungueal em melanoniquias

Nilton Di Chiacchio Débora Cadore de Farias Bianca Maria Piraccini Sergio Henrique Hirata Bertrand Richert Martin Zaiac Ralph Daniel Pier Alessandro Fanti Josette Andre Beth S Ruben Philip Fleckman Phoebe Rich Eckart Haneke Patricia Chang Judith Dominguez Cherit Richard Scher Antonella Tosti About the authors

Abstracts

This statement, focused on melanonychia and nail plate dermoscopy, is intended to guide medical professionals working with melanonychia and to assist choosing appropriate management for melanonychia patients. The International Study Group on Melanonychia was founded in 2007 and currently has 30 members, including nail experts and dermatopathologists with special expertise in nails. The need for common definitions of nail plate dermoscopy was addressed during the Second Meeting of this Group held in February 2008. Prior to this meeting and to date (2010) there have been no evidence-based guidelines on the use of dermoscopy in the management of nail pigmentation.

Dermoscopy; Melanoma; Nails; Nail diseases


Este consenso, com foco em melanoníquia e dermatoscopia da lâmina ungueal, se destina a orientar os médicos que trabalham com melanoníquia e auxiliar no manejo destes pacientes. O grupo internacional de estudos sobre melanoníquia foi fundada em 2007 e tem agora 30 membros, incluindo dermatologistas e dermatopatologistas com conhecimento especializado em unhas. A necessidade de definições comuns de dermatoscopia da lâmina ungueal foi abordada durante a segunda reunião deste grupo, realizada em fevereiro de 2008. Antes desta reunião e até a presente, não existem orientações com base em evidências sobre a utilização de dermatoscopia da placa ungueal.

Dermoscopia; Doenças da unha; Melanoma; Unhas


This statement, focused on melanonychia and nail plate dermoscopy, is intended to guide medical professionals working with melanonychia and to assist choosing appropriate management for melanonychia patients.

The International Study Group on Melanonychia was founded in 2007 by Professor Antonella Tosti and Professor Nilton Di Chiacchio. The Group includes nail experts and dermatopathologists with expertise in nails from twelve different countries.

Prior to this meeting and to date there have been no evidence-based guidelines on the use of dermoscopy in the management of nail pigmentation.

16 members of the International Study Group on Melanonychia participated in this study.

A detailed literature search on nail dermoscopy, nail pigmentation and melanonychia including Medline, Embase, Cochrane and a hand search were carried out ( 11. Ronger S, Touzet S, Ligeron C, Balme B, Villard AM, Barrut D, Collin C, Thomas L. Dermatoscopic examination of nail pigmentation. Arch Dermatol. 2002;138:1327-33.

2. Haas N, Henz BM. Pitfall in pigmentation: pseudopods in the nail plate. Dermatol Surg 2002;28:966-7

3. Gencoglan G, Gerceker-Turk B, Kilinc-Karaarslan I, Akalin T, Ozdemir F. Dermoscopic findings in Laugier-Hunziker syndrome. Arch Dermatol. 2007;143:631-633

4. Caseret AS, Skowron F, Viallard AM, Balme B, Thomas L. Subungual blue nevus. J Am Acad Dermatol. 2003;49:310-2.

5. Hirata SH, Yamada S, Almeida FA, Enokihara MY, Rosa IP, Enokihara MM, et al. Dermoscopic examination of the nail bed and matrix. Int J Dermatol. 2006;45:28-30.

6. Imakado S, Sato H, Hamada K. Two cases of subungueal melanoma in situ. J Dermatol. 2008;35:754-8.

7. Antonovich DD, Grin C, Grant-Kels JM. Childhood subungual melanoma in situ in diffuse nail melanosis beginning as expanding longitudinal melanonychia. Pediatr Dermatol. 2005;22:210-2.

8. Iorizzo M, Tosti A, Di Chiacchio N, Hirata SH, Misciali C, Michalany N, et al. Nail melanoma in children: differential diagnosis and management. Dermatol Clin. 2008;34:974-8.

9. Braun RP, Baran R, Saurat JH, Thomas L. Surgical Pearl: Dermoscopy of the free edge of the nail to determine the level of nail plate pigmentation and the location of its probable origin in the proximal or distal nail matrix. J Am Acad Dermatol. 2006;55:512-3.
- 1010. Bilemjian APJ, Maceira JP, Barcaui CB, Pereira FB. Melanoniquia: importância da avaliação dermatoscópica e da observação da matriz / leito ungueal. An Bras Dermatol. 2009;84:185-9. ). Based on the available literature, the Group decided to develop an informal consensus process at S1 level.

The Group reviewed publications on melanonychia and nail plate dermoscopy (Pub med indexed or not), approved by the American Academy of Dermatology, Miami, 2010 (Table 1).

Table 1
Review of the literature

This clinical consensus statement proposes consideration of a number of important points. About the technique used for nail dermoscopy, devices, polarized and non- polarized that can be used for nail plate dermoscopy. No evidence or consensus exists on which instrument and what kind of light source is the most effective. The color and definition of the lines may vary among the different devices. The group suggests using the same device in the follow-up evaluation of the patient, with magnification of 10X (the best). This allows the whole nail plate to be seen in the field, as well as the regularity of lines to be evaluated. The best immersion fluid for the nail plate is ultrasound gel.

According to the patterns found, the group agrees that nail plate dermoscopy is useful to distinguish blood from melanin. Subungual hemorrhages have a distinct pattern of globules, with or without distal streaks, with a range of color varying from red to brown to black (Figure 1A). The risk of coincidental bleeding from a subungual tumor must be taken into consideration. The dermoscopic diagnosis of subungual hematoma does not rule out a coincident nail tumor.

FIGURE 1
A - Subungual hemorrhages showing pattern of globules: B - Benign melanonychia due to melanocyte activation - difficult to distinguish a light brown from a gray background: C - Benign lesions in children (nevus) showing a brown background with longitudinal lines of different color and width: D – A melanoma with dark background with areas of different hue of pigmentation

According to the literature, the pattern of benign melanonychia due to melanocyte activation (ethnic-type or drug-induced pigmentation) and lentigo exhibits a homogeneous gray coloration of the background with thin longitudinal gray lines. The group agrees that it is difficult to distinguish a light brown from a gray background and that a gray background is infrequently observed (Figure 1 B). The color of the background is not a distinctive feature of benign lesions due to melanocyte activation. The color due to the melanin deposition may vary depending on the thickness of the nail and melanin location within the nail plate because of the "Tyndall" effect.

The brown background associated with regular parallel lines of identical color, spacing, and width suggests a benign lesion, either nevus or lentigo. The group agrees, even though this regular pattern is not often observed. Most benign lesions in children and adults show a brown background with longitudinal lines of different color and width. Line distribution within the band is most frequently irregular (Figure 1 C).

The brown background associated with longitudinal lines that are irregular in color, width, spacing, and parallelism is suggestive of malignant melanoma. The group agrees that benign nevi in children often show this pattern. Even in benign lesions of adults, individual lines may be irregular in width and color. The important point is the homogeneity of color and width of each individual longitudinal line. If an individual line shows irregularity in color or width along its length this is considered suspicious of melanoma. Melanoma in adults often shows a diffuse dark background with barely visible lines (Figure 1 D). The group agrees that a dark background with areas of different hue of pigmentation is suggestive of melanoma even in the absence of irregular lines.

Other applications of dermoscopy at the nail apparatus are reported. Distal edge dermoscopy is helpful for identifying the origin of the pigment producing lesion (distal or proximal matrix). The group agrees that distal edge dermoscopy is not always useful, particularly when the nail plate is thin. The same applies to very dark or very light bands. Dermoscopy of the hyponychium allows to distinguish pigmentation due to melanocytic nevi characterized by linear pigmentation in the furrows or across the skin marks, from pigmentation associated with nail melanoma (Hutchinson's sign), where dermoscopy shows haphazard pigmentation distributed in a parallel ridge pattern in a disorderly fashion.1111. Kawabata Y, Ohara K, Hino H, Tamaki K. Two kinds of Hutchinson's sign, benign and malignant. J Am Acad Dermatol. 2001;44:305-7. The group agrees that dermoscopy of the hyponychium is useful in cases where melanonychia is associated with pigmentation of the hyponychium.

The group agrees that the nail plate dermoscopic patterns stated in the literature, as indicative of nail melanoma, need to be modified as follows:

  • Brown bands with lines irregular in color, width and spacing are not indicative of melanoma in children;

  • Benign lesions in adults can present with irregular lines and spacing; and

  • Melanoma in adults is often present with a very dark background where the lines are difficult to see.

The group also agrees that at present any decision to excise should be based on established clinical criteria (history and physical exam) and not on nail plate dermoscopy patterns. Dermoscopy of the hyponychium is very useful for differential diagnosis between nevi and melanoma in the case of pigmentation of the periungual tissues.

REFERENCES

  • 1
    Ronger S, Touzet S, Ligeron C, Balme B, Villard AM, Barrut D, Collin C, Thomas L. Dermatoscopic examination of nail pigmentation. Arch Dermatol. 2002;138:1327-33.
  • 2
    Haas N, Henz BM. Pitfall in pigmentation: pseudopods in the nail plate. Dermatol Surg 2002;28:966-7
  • 3
    Gencoglan G, Gerceker-Turk B, Kilinc-Karaarslan I, Akalin T, Ozdemir F. Dermoscopic findings in Laugier-Hunziker syndrome. Arch Dermatol. 2007;143:631-633
  • 4
    Caseret AS, Skowron F, Viallard AM, Balme B, Thomas L. Subungual blue nevus. J Am Acad Dermatol. 2003;49:310-2.
  • 5
    Hirata SH, Yamada S, Almeida FA, Enokihara MY, Rosa IP, Enokihara MM, et al. Dermoscopic examination of the nail bed and matrix. Int J Dermatol. 2006;45:28-30.
  • 6
    Imakado S, Sato H, Hamada K. Two cases of subungueal melanoma in situ. J Dermatol. 2008;35:754-8.
  • 7
    Antonovich DD, Grin C, Grant-Kels JM. Childhood subungual melanoma in situ in diffuse nail melanosis beginning as expanding longitudinal melanonychia. Pediatr Dermatol. 2005;22:210-2.
  • 8
    Iorizzo M, Tosti A, Di Chiacchio N, Hirata SH, Misciali C, Michalany N, et al. Nail melanoma in children: differential diagnosis and management. Dermatol Clin. 2008;34:974-8.
  • 9
    Braun RP, Baran R, Saurat JH, Thomas L. Surgical Pearl: Dermoscopy of the free edge of the nail to determine the level of nail plate pigmentation and the location of its probable origin in the proximal or distal nail matrix. J Am Acad Dermatol. 2006;55:512-3.
  • 10
    Bilemjian APJ, Maceira JP, Barcaui CB, Pereira FB. Melanoniquia: importância da avaliação dermatoscópica e da observação da matriz / leito ungueal. An Bras Dermatol. 2009;84:185-9.
  • 11
    Kawabata Y, Ohara K, Hino H, Tamaki K. Two kinds of Hutchinson's sign, benign and malignant. J Am Acad Dermatol. 2001;44:305-7.

  • *
    Paper produced by the International Study Group Meeting on Melanonychia (2010) - Miami, USA.

Publication Dates

  • Publication in this collection
    Apr 2013

History

  • Received
    05 Apr 2012
  • Accepted
    15 June 2012
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