AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Congenital nevi are present at birth and result from a proliferation of benign melanocytes in the dermis, epidermis, or both. Occasionally, nevi that are not present at birth but are histologically identical to congenital nevi may develop during the first 2 years of life. This is referred to as congenital nevus tardive (Clemmensen, 1988).

Congenital nevi are one of several known risk factors for the eventual development of melanoma. Fortunately, melanoma remains an uncommon malignancy in prepubertal children, with an annual incidence of 0.7 cases per million children aged 0-9 years. Patient concerns regarding changing or worrisome-looking nevi are, nonetheless, very common. Moreover, by the time a child reaches adolescence, the incidence of melanoma increases substantially, with a rate of 13.2 cases per million children aged 15-19 years.

While many sources have noted the so-called melanoma epidemic in adults, only in recent years have data documented an alarming increase in melanoma in adolescents. This increase, combined with the recognition of clearly identifiable melanoma risk factors in childhood, allows physicians of the 21st century to play a crucial role in the identification of children at risk for melanoma and to aid in the prevention of melanoma through education regarding the risks of ultraviolet light exposure.

Pathophysiology

The etiology of congenital melanocytic nevi remains unclear. The melanocytes of the skin originate in the neuroectoderm, although the specific cell type from which they derive remains unknown. One hypothesis is that pluripotential nerve sheath precursor cells migrate from the neural crest to the skin along paraspinal ganglia and peripheral nerve sheaths and differentiate into melanocytes upon reaching the skin (Cramer, 1988). One possible explanation for the presence of congenital melanocytic nevi is that an external insult results in a mutation that affects the morphogenesis of the embryonic neuroectoderm and migration of precursor cells to the skin.

Congenital nevi have been stratified into 3 groups according to size. Small nevi are less than 1.5 cm in greatest diameter, medium nevi are 1.5-19.9 cm in greatest diameter, and large or giant nevi are greater than 20 cm in greatest diameter. Giant nevi are often surrounded by several smaller satellite nevi. An alternate definition is that a small congenital nevus is one for which primary closure is possible after excision.

Congenital nevi may also be seen as a component of neurocutaneous melanosis, a rare congenital syndrome characterized by the presence of congenital melanocytic nevi and melanotic neoplasms of the central nervous system. Rokitansky first described neurocutaneous melanosis in 1861. The current diagnostic criteria for neurocutaneous melanosis are (1) large (>20 cm) or multiple (>3) congenital nevi in association with meningeal melanosis or melanoma, (2) no evidence of meningeal melanoma except in patients in whom cutaneous lesions are histologically benign, and (3) no evidence of cutaneous melanoma except in patients in whom meningeal lesions are histologically benign (Kadonaga, 1991).

Neurocutaneous melanosis may result from an error in the morphogenesis of the neuroectoderm, which gives rise to the melanotic cells of both the skin and meninges. Clinically, patients may present with increased intracranial pressure due to hydrocephalus or a mass lesion. The prognosis of patients with symptomatic neurocutaneous melanosis is very poor, even in the absence of malignancy. In one review of 39 reported cases of symptomatic neurocutaneous melanosis, death occurred in more than half the patients within 3 years of the onset of neurological symptoms, and most deaths were in patients younger than 10 years (Kadonaga, 1991).

Frequency

International

Congenital nevi are present in 1-2% of newborn infants.

Mortality/Morbidity

Congenital nevi, depending on size and location, may have a significant impact on cosmesis. Giant congenital nevi place individuals at an increased risk for the development of melanoma at the site of the nevus. For giant congenital melanocytic nevi, the risk of developing melanoma has been reported to be as high as 5-7% by age 60 years (Rhodes, 1981; Bett, 2005). One study suggests that the risk of melanoma may be greater in those with giant congenital melanocytic nevi with more satellite lesions or a larger diameter (Hale, 2005). However, while the general consensus regarding smaller nevi is that they pose a greater risk for the development of melanoma than normal skin, this risk has not been quantified.

Race

No racial predilection is recognized.

Sex

Congenital nevi occur in both sexes, with no known predilection.

Age

To be considered congenital nevi, lesions must be present at birth.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

History

The presence of congenital nevi may be reported by adults, adolescents, or the parents of infants and children.

Physical

Nevi may be located anywhere on the body. Classification as a congenital nevus depends in large part on an accurate history or photographs or medical reports from birth.

Causes

The etiology of congenital melanocytic nevi has not been elucidated. One possible cause is a mutation due to an external insult.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Other Problems to be Considered

Becker nevus
Epidermal nevus
Nevus spilus
Pigmented non-melanoma carcinoma

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Biopsy confirms a benign or malignant nature in suggestive lesions.

Imaging Studies

• In cases associated with a high index of suspicion for the presence of neurocutaneous melanosis, magnetic resonance imaging of the central nervous system is a useful diagnostic tool.

Other Tests

• Dermoscopy usually reveals a heterogenous globular pattern.

Histologic Findings

Because of the increased risk of melanoma associated with congenital nevi, attempts have been made to distinguish congenital nevi from acquired nevi on the basis of histology. Distinguishing histologic features include (1) involvement by nevus cells of deep dermal appendages and neurovascular structures (including hair follicles, sebaceous glands, arrector pili muscles, and within walls of blood vessels), (2) extension of nevus cells to deep dermis and subcutaneous fat, (3) infiltration of nevus cells between collagen bundles, and (4) a nevus cell–poor subepidermal zone (Mark, 1973; Rhodes, 1985; Everett, 1989). In contrast to congenital nevi, acquired nevi are usually composed of nevus cells that are limited to the papillary and upper reticular dermis and do not involve the appendages.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

The management of congenital melanocytic nevi depends on a number of factors, including the size of the lesion, the location of the lesion, the age of patient, the effect on cosmesis, and the potential for malignant transformation.

• Although the risk of malignant transformation in small and medium-sized congenital melanocytic nevi has not been established, many physicians agree that the risk is probably not significant enough to warrant the prophylactic removal of all of these lesions. However, some patients may desire removal of these lesions to improve cosmesis. Until evidence is presented on which to base definitive treatment guidelines, many physicians are managing small and medium-sized congenital melanocytic nevi with baseline photography and regular follow-up.

Surgical Care

Surgical removal of congenital melanocytic nevi is performed for 2 main reasons, (1) to improve the cosmetic appearance of the patient and (2) to reduce the likelihood of malignant transformation. The increased risk of malignant transformation associated with giant congenital melanocytic nevi is well established. Ideally, these lesions are removed whenever possible. Barriers to removal may include the size of the lesion and its proximity to vital structures. Several different procedures are available to remove these lesions.

• Surgical excision of giant congenital melanocytic nevi, depending on the size and location of the lesion, may be challenging. Often, the size of the lesion necessitates a staged excision. Tissue expanders, tissue grafts, and tissue flaps are often necessary to close the large defects following excision. Because the melanocytes in such cases may extend deep into underlying tissues (including muscle, bone, and central nervous system), removing the cutaneous component may not eliminate the risk of malignancy.
• Curettage of the lesions may be performed during the neonatal period (De Raeve, 2002), but long-term studies suggest the nevus will, in part, recur. This is likely due to those components of the epidermis that are deep to the level of curettage.
• Laser treatment of the lesions has been performed with a number of different types of lasers, including the systems noted below. Because of the lack of penetrance to deeper tissue levels, long-term recurrence is also an issue with these techniques.
• • High-energy pulsed carbon dioxide laser (Michel, 2001; Michel, 2003; Reynolds, 2003)
  • Erbium:YAG laser (Lapiere, 2002; Michel, 2003)
  • Normal-mode ruby laser (Kono, 2003; Michel, 2003; Kono, 2005)
  • Q-switched ruby laser (Michel, 2003; Kono, 2005)
  • Switched alexandrite laser (Kono, 2003; Kim, 2005)

Consultations

Because of the risk of neurocutaneous melanosis in patients with giant congenital nevi or multiple smaller congenital nevi, consultation with a neurologist, pediatrician, or both may be useful to detect possible early neurologic manifestations of the disease. Even in the absence of malignancy, neurocutaneous melanosis may cause problems such as obstructive hydrocephalus.

Diet

No specific dietary recommendations are necessary for patients with congenital nevi.

Activity

No specific activity restrictions are necessary for patients with congenital nevi. However, because of the increased risk for the development of melanoma, especially in patients with giant congenital nevi, proper protective measures should be taken to minimize ultraviolet light exposure. Maintaining the ability to take part in normal activities should be a consideration when planning surgical removal of a congenital nevus.

FOLLOW-UP

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Complications

• Patients with giant congenital melanocytic nevi have an increased risk of developing melanoma (as high as 5-7% by age 60 y). The lifetime risk of malignant transformation associated with smaller nevi is surely smaller than that for giant nevi but is unknown at this time.

Prognosis

• The prognosis for patients with small or medium-sized congenital melanocytic nevi is good. Although the risk of developing melanoma in these lesions has not been quantified, it is generally regarded as only slightly higher than that of normal skin. Despite the increased risk for melanoma in patients with giant congenital melanocytic nevi, the vast majority of patients never develop melanoma. Therefore, prognosis remains good in these patients, especially if the lesions are examined regularly for signs of atypia.
• Prognosis in cases of symptomatic neurocutaneous melanosis is quite poor.

Patient Education

• All people need to be educated on the importance of protection from ultraviolet light exposure. This is especially important in people who have congenital melanocytic nevi, particularly the giant type, because they are already at an increased risk for the development of melanoma.
• For excellent patient education resources, visit eMedicine's Skin, Hair, and Nails Center. Also, see eMedicine's patient education articles Skin Cancer and Mole Removal.

MISCELLANEOUS

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failure to detect neurocutaneous melanosis in patients with giant congenital melanocytic nevi or multiple smaller congenital nevi
• Failure to diagnose malignancy in congenital melanocytic nevi
• Misdiagnosis of other lesions as a congenital melanocytic nevus

MULTIMEDIA

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  The photomicrograph shows a symmetrical broad proliferation of melanocytes in the papillary and reticular dermis with maturation with progressive descent; splaying between collagen bundles; and permeation of muscles of hair erection, blood vessels, and adnexa (hematoxylin and eosin stain, 20X magnification).
	View Full Size Image
Media type:  Image

Media file 2:  Higher-power view of Image 1 (hematoxylin and eosin stain, 40X magnification).
	View Full Size Image
Media type:  Image

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

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• Kono T, Ercocen AR, Chan HH, et al. Effectiveness of the normal-mode ruby laser and the combined (normal-mode plus q-switched) ruby laser in the treatment of congenital melanocytic nevi: a comparative study. Ann Plast Surg. Nov 2002;49(5):476-85. [Medline].
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• Kono T, Ercocen AR, Nozaki M. Treatment of congenital melanocytic nevi using the combined (normal-mode plus Q-switched) ruby laser in asians: clinical response in relation to histological type. Ann Plast Surg. May 2005;54(5):494-501. [Medline].
• Krengel S, Hauschild A, Schafer T. Melanoma risk in congenital melanocytic naevi: a systematic review. Br J Dermatol. Jul 2006;155(1):1-8. [Medline].
• Lapiere K, Ostertag J, Van De Kar T, Krekels G. A neonate with a giant congenital naevus: new treatment option with the erbium:YAG laser. Br J Plast Surg. Jul 2002;55(5):440-2. [Medline].
• MacLachlan WWG. Extensive pigmentation of the brain associated with nevi pigmentosi of the skin. J Med Res. 1913;29:433-47.
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• Michel JL. Laser therapy of giant congenital melanocytic nevi. Eur J Dermatol. Jan-Feb 2003;13(1):57-64. [Medline].
• Michel JL, Caillet-Chomel L. Treatment of giant congenital nevus with high-energy pulsed CO2 laser. Arch Pediatr. Nov 2001;8(11):1185-94. [Medline].
• Patterson WM, Lefkowitz A, Schwartz RA, et al. Melanoma in children. Cutis. May 2000;65(5):269-72, 275. [Medline].
• Reynolds N, Kenealy J, Mercer N. Carbon dioxide laser dermabrasion for giant congenital melanocytic nevi. Plast Reconstr Surg. Jun 2003;111(7):2209-14. [Medline].
• Rhodes AR, Silverman RA, Harrist TJ, Melski JW. A histologic comparison of congenital and acquired nevomelanocytic nevi. Arch Dermatol. Oct 1985;121(10):1266-73. [Medline].
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• Rokitansky J. Ein ausgezeichneter Fall von Pigment-mal mit ausgebreiteter Pigmentierung der inneren Hirn- und Ruchenmarkshaute. Allg Wien Med Z. 1861;6:113-6.
• Silfen R, Skoll PJ, Hudson DA. Congenital giant hairy nevi and neurofibromatosis: the significance of their common origin. Plast Reconstr Surg. Oct 2002;110(5):1364-5. [Medline].
• Wiltz H, Kollmer WL, Rauscher GE, et al. Excision of the large congenital melanocytic nevus facilitated by the use of the tissue expander. J Surg Oncol. Jun 1988;38(2):104-7. [Medline].
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Article Last Updated: Dec 4, 2006