BRIEF REPORT Pediatric Dermatology 1–2, 2012
Congenital Nevus of the Nail Apparatus—Diagnostic Approach of a Case through Dermoscopy Abstract: Melanonychia striata in childhood is primarily due to congenital nevi, but melanoma should be excluded. We report a case in which dermoscopy was used in an attempt to avoid incisional biopsy.
at the age of 18 months as a narrow pigmented streak. Clinical and dermoscopic follow-up revealed irregular longitudinal pigmented streaks of variant color and width over a brown background (Fig. 1). Pigmentation extended to the periungual skin (Hutchinson’s sign) and demonstrated a parallel furrow pattern. Because clinical and dermoscopic appearance were suggestive of benign lesion, and the parents were reluctant to consent to nail matrix biopsy, a conservative approach was initially adopted, but because of evolving changes, including the marked irregularity of the pigmented streaks, it was decided to proceed with biopsy. This confirmed the diagnosis of a congenital melanocytic nevus. DISCUSSION
Melanonychia striata is brown, black, or gray pigmentation of the nail plate, forming parallel bands, occasionally extending to the periungual skin. In childhood, congenital melanocytic nevi are the primary cause, but when a single band of pigmentation is evident, melanoma is an important diagnostic consideration (1,2). Dermoscopy is a valuable tool in the diagnosis and management of these lesions (1–5). CASE REPORT We report the case of an 8-year-old boy with a pigmented lesion on the right fourth toenail. Pigmentation appeared
Melanonychia striata in Caucasian children is usually a benign lesion such as lentigo or subungual nevus. Effectively, subungual melanoma in Caucasian children is rare, with only two cases of melanoma in situ published so far among a total of 12 published cases. These were two cases of longitudinal melanonychia demonstrating irregular streak in dermoscopy (1). All the other melanoma cases were diagnosed in dark-skinned or Asian children. This low incidence makes it unclear whether there is a racial predisposition in childhood melanoma. Based on the fact that risk of melanoma is small, some authors suggest watchful waiting, performing biopsies only if dermatoscopic features of melanoma or
Figure 1. Dermoscopic images of the affected nail at different ages. DOI: 10.1111/j.1525-1470.2012.01813.x
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2 Pediatric Dermatology 2012
rapidly evolving changes are present (2,4–6), but the accuracy of dermoscopic patterns has not been established, and follow-up intervals need to be determined. The concern is with congenital lesions demonstrating constant changes with irregular patterns of longitudinal streaks; irregularity in spacing, thickness, and color of the lines; and Hutchinson’s sign (1,2). Hutchinson’s sign, although it has been associated with melanoma, can also be present in subungual nevi, especially of the congenital type (7). Because there have not been many cases of subungual melanoma in children, Hutchinson’s sign types observed in benign and malignant lesions cannot be compared, although the parallel furrow pattern on the periungual skin, as in the case described, could be an indicationg that a lesion is benign, as is the case in acral skin nevi. Therefore, although in many cases of congenital melanonychias, nail plate dermoscopy cannot provide guidance on the management of these lesions, the dermoscopic features of the perionychium can be useful. Our case suggests that dermoscopy and digital dermoscopic monitoring, not only of the nail plate, but also of the periungual skin, can guide clinicians in the management of congenital melanonychias, although in ambiguous cases, biopsy is warranted. Future studies are needed to better define the dermoscopic patterns of congenital melanocytic nevi of the nail matrix and their changes during digital dermoscopic follow-up.
REFERENCES 1. Tosti A, Piraccini BM, Cagalli A et al. In situ melanoma of the nail unit in children: report of two cases in fair-skinned Caucasian children. Pediatr Dermatol 2012;29:79–83. 2. Luc T, Dalle S. Dermoscopy provides useful information for the management of melanonychia striata. Dermatol Ther 2007;20:3–10. 3. Antonovich DD, Grin C, Grant-Kels JM. Childhood subungual melanoma in situ in diffuse nail melanosis beginning as expanding longitudinal melanonychia. Pediatr Dermatol 2005;22:210–212. 4. Iorizzo M, Tosti A, Di Chiacchio N et al. Nail melanoma in children: differential diagnosis and management. Dermatol Surg 2008;34:974–978. 5. Ronger S, Touzet S, Ligeron C et al. Dermoscopic examination of nail pigmentation. Arch Dermatol 2002;138:1327– 1333. 6. Tosti A, Argenziano G. Dermoscopy allows better management of nail pigmentation. Arch Dermatol 2002; 138:1369–1370. 7. Tosti A, Piraccini BM, de Farias DC. Dealing with melanonychia. Semin Cutan Med Surg 2009;28:49–54. Elizabeth Lazaridou, M.D.* Christina Giannopoulou, M.D.* Christina Fotiadou, M.D.* Efterpi Demiri, M.D. Demetrios Ioannides, M.D.* Departments of *Dermatology and Venereology and Plastic Surgery, Aristotle University Medical School, Thessaloniki, Greece Address correspondence to Elizabeth Lazaridou, M.D., 133 Tsimiski street, 546 21 Thessaloniki, Greece, or e-mail:
[email protected].
