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Congenital melanocytic nevi

Congenital melanocytic nevi
Literature review current through: Jan 2024.
This topic last updated: Jan 12, 2023.

INTRODUCTION — Congenital melanocytic nevi (CMN) are classically defined as melanocytic nevi present at birth or within the first few months of life. CMN and speckled lentiginous nevi (a subtype of CMN) will be discussed below. Acquired melanocytic nevi and other benign pigmented skin lesions are discussed separately. Atypical nevi are also discussed separately.

(See "Acquired melanocytic nevi (moles)".)

(See "Benign pigmented skin lesions other than melanocytic nevi (moles)".)

(See "Atypical (dysplastic) nevi".)

EPIDEMIOLOGY — In prospective studies conducted in the United States, Mexico, China, Finland, Australia, and Japan, 1 to 3 percent of newborns had pigmented lesions that were clinically compatible with a diagnosis of CMN [1]. Large or giant CMN occur in approximately 1 in 20,000 births [2].

PATHOGENESIS — CMN are hamartomas composed primarily of clonal proliferations of benign melanocytes that arise during embryogenesis [3,4]. Somatic BRAF V600E mutations have been found in a high proportion of small CMN as well as in acquired melanocytic nevi and cutaneous melanomas [5,6]. In contrast, 70 to 95 percent of large and giant CMN harbor somatic gain-of-function mutations in NRAS [7,8].

In patients with neurocutaneous melanocytosis (see 'Neurocutaneous melanosis' below), the same NRAS mutations have been found in multiple CMN and affected areas of melanocytic proliferation in the central nervous system [9]. Activating mutations of BRAF or NRAS result in cellular proliferation via increased signaling through several pathways, in particular mitogen-activated protein kinase (MAPK).

CLASSIFICATION — CMN lesions are categorized into subgroups based on the largest diameter that the nevus is projected to attain by adulthood [10] (see 'Projected estimate of adult size' below):

Congenital melanocytic nevi categories – CMN categories include:

Small – <1.5 cm (picture 1).

Medium-sized – M1 1.5 to 10 cm; M2 10 to 20 cm (picture 2).

Large – L1 >20 to 30 cm; L2 >30 to 40 cm (picture 3). In a neonate, large CMN are >9 cm on the head or >6 cm on the body.

Giant – G1 >40 to 60 cm; G2 >60 cm.

Satellite nevi – Large and giant CMN are further categorized by the number of satellite lesions present, as follows:

S – 0

S1 – <20

S2 – 20 to 50

S3 – >50

Additional features – Color heterogeneity, surface rugosity, the presence of dermal or subcutaneous nodules, and hypertrichosis can each be graded from 0 (none) to 2 (marked).

CLINICAL PRESENTATION

General features — CMN are generally present at birth or within the first few months of life. Small melanocytic nevi that become apparent during early childhood (especially between three months and two years of age) often have clinical and histologic features identical to those of "true" CMN and have been referred to as "tardive CMN," "early-onset nevi," and "congenital nevus-like nevi" [11].

Most CMN are small or medium-sized and solitary. The color ranges from tan to black or blue-black, and the borders are often geographic and irregular. Many, but not all, CMN have an increased density of dark, coarse (terminal) hairs, and the overlying hypertrichosis may develop over years.

Large CMN are frequently accompanied by multiple smaller, widely disseminated "satellite" nevi (picture 3). For large and giant nevi, the number of "satellite nevi" surrounding the nevus helps inform evaluation and monitoring for these patients.

Anatomic distribution — CMN can occur in any cutaneous area of the body. Because of their distribution, giant CMN are sometimes referred to as "garment" or "bathing trunk" nevi. Most giant CMN can be categorized into one of six anatomical distributions, termed the "six Bs" [12]:

Bolero – Upper back and neck

Back – Central back, spares buttocks and shoulders

Bathing trunk – Mainly genital area and buttocks, does not extend to shoulders or neck

Breast/belly – Localized to breast and/or abdomen

Body extremity – Only on extremity, spares genitals or shoulders

Body – Involves most of body, overlap of bolero and bathing trunk

Projected estimate of adult size — CMN grow proportionately with the child's growth. To project an estimated adult CMN size, the following factors are multiplied by the greatest length of the CMN as measured in the infant: 1.7-fold on the head, 3.3-fold on the lower extremities, and 2.8-fold on the trunk and upper extremities.

DERMOSCOPIC FEATURES — The main dermoscopic features seen in CMN, as well as in acquired melanocytic nevi, are pigment network; aggregated globules; and/or diffuse, homogeneous, brown pigmentation (figure 1) [13]. Common dermoscopic patterns seen in CMN are reticular, globular/cobblestoning, homogenous, and a mixture of these (ie, multicomponent) [14]. (See "Overview of dermoscopy" and "Dermoscopic evaluation of skin lesions".)

However, CMN may exhibit exaggerated dermoscopic features compared with acquired melanocytic nevi, such as perifollicular hypopigmentation (picture 4); skin furrow hyperpigmentation; and prominent, follicular structures [15,16]. Additional features include hypertrichosis (picture 5), perifollicular pigment changes (picture 6), target globules (picture 7), focal areas of hypopigmentation, and network thickening (picture 8). Some authors have noted that a target network with dots, globules, or blood vessels (picture 9) is a more distinctive feature of CMN [16].

Dermoscopic features detected in CMN of the palms and soles include the parallel furrow pattern, which is also common in acquired acral nevi (picture 10) [17]. A more prominent crista dotted pattern (picture 11) or peas-in-a-pod pattern (picture 12) may also be seen, reflecting an increased number of nevus cell nests around distal eccrine ducts. (See "Dermoscopy of pigmented lesions of the palms and soles".)

PATHOLOGY — Melanocytic nevi (moles) represent benign proliferations of a type of melanocyte known as a "nevus cell." The two major differences between ordinary melanocytes that reside in the basal layer of the epidermis and nevus cells are:

Nevus cells cluster as nests within the lower epidermis and/or dermis, whereas epidermal melanocytes are evenly dispersed as single units.

Nevus cells do not have dendritic processes (with the exception of nevus cells within blue nevi).

Both melanocytes and nevus cells produce the pigment melanin. In contrast to acquired melanocytic nevi, CMN tend to extend deeper into the dermis and subcutaneous tissues [18]. Melanocytes in CMN more often track along or within neurovascular and adnexal structures (eg, hair follicles, sebaceous glands, eccrine ducts) or are located between collagen bundles in a single-file array [19-21].

DIAGNOSIS — The diagnosis of a medium-sized, large, or giant CMN is usually straightforward, based upon the clinical appearance and a history of presence since birth or early infancy. Small congenital nevi may be difficult to distinguish from acquired nevi if history is uncertain. However, dermoscopic examination may be helpful in differentiating small CMN from atypical acquired nevi. (See "Dermoscopic evaluation of skin lesions" and "Atypical (dysplastic) nevi".)

DIFFERENTIAL DIAGNOSIS — The major entities in the differential diagnosis of a small or medium-sized CMN are a smooth muscle hamartoma and mastocytoma. The presence of a pseudo-Darier sign (surface induration occurring due to smooth muscle-based piloerection upon stroking lesion) or a Darier sign (wheal and flare reaction with erythema and edema due to mast cell degranulation upon stroking lesion (picture 13)) can help distinguish these entities, respectively. Dermoscopy and/or biopsy may be helpful if the clinical diagnosis is unclear. (See "Mastocytosis (cutaneous and systemic) in adults: Epidemiology, pathogenesis, clinical manifestations, and diagnosis".)

The differential diagnosis of medium-sized or large CMN may include a plexiform neurofibroma. A plexiform neurofibroma is favored if the lesion has a "bag of worms" texture on palpation or if there are other findings suggestive of neurofibromatosis type 1. (See "Neurofibromatosis type 1 (NF1): Pathogenesis, clinical features, and diagnosis".)

NATURAL HISTORY

Overview — CMN enlarge in proportion to the child's growth and tend to grow more rapidly during early infancy [22]. In addition to increasing in size, CMN undergo other age-related changes in appearance. They often begin as flat, evenly pigmented patches that later become elevated with a pebbly (picture 2), verrucous, or cerebriform surface and darker, lighter, mottled, or speckled pigmentation [23]. Dermal melanocytes within CMN may undergo peripheral nerve sheath differentiation or neurotization, which results in the development of soft nodules and large, plexiform, neurofibroma-like plaques [4].

CMN located on the scalp may have a particular tendency to gradually lighten and regress over time [24]. The halo phenomenon (ie, the development of a depigmented halo around the nevus), which is more commonly observed with acquired melanocytic nevi but does occur in CMN, represents another means by which CMN in any site can regress (picture 14) [25]. In some cases, the development of halo nevus depigmentation is preceded by dermatitis on and/or around the nevus [26].

During the neonatal period, transient erosions or ulcerations may arise at sites of obvious friction within medium-sized and large CMN as a reflection of increased skin fragility. (See 'Management' below.)

Proliferative nodules — Proliferative nodules are benign melanocytic proliferations that occasionally develop within large or giant CMN [27]. They may be congenital or appear during infancy or childhood.

Because of their rapid growth and clinical characteristics (eg, firmness or ulceration), biopsy is recommended to exclude melanoma (see 'Monitoring for melanoma' below). However, the histopathologic distinction of proliferative nodules from melanoma may prove difficult because of the presence of large, atypical melanocytes and mitoses (picture 15). This is a situation where evaluation by experienced dermatopathologists is essential. Techniques such as comparative genomic hybridization can help to distinguish proliferative nodules (usually having no chromosomal aberrations or only whole chromosomal copy number aberration) from melanoma (typically demonstrating gains/losses of chromosomal fragments) [27,28]. Mass spectroscopy imaging proteomic analysis may also help differentiate proliferative nodules from melanoma [28]. (See "Pathologic characteristics of melanoma", section on 'Genetic and molecular characterization of melanoma'.)

COMPLICATIONS

Risk of melanoma — Individuals with CMN, and especially those with large or giant CMN, have an increased risk of developing a melanoma [29]:

Small/medium-sized congenital melanocytic nevi – The risk of melanoma arising within small and medium-sized CMN is thought to be less than 1 percent over a lifetime [3]. In small and medium-sized CMN, melanoma most often occurs after puberty and tends to arise at the dermal-epidermal junction, in contrast to the earlier onset and deeper origin of many melanomas arising within large or giant CMN.

Large/giant congenital melanocytic nevi – For patients with large or giant CMN, the risk of developing melanoma (cutaneous or extracutaneous) is estimated to be approximately 2 to 5 percent over a lifetime, with approximately one-half occurring by five years of age [30,31]. Patients with a "giant" (>40 cm) CMN in a posterior axial location with numerous satellite nevi have the greatest risk of developing melanoma. In a cohort study including 349 children with CMN (145 with large CMN), 5 children (3.4 percent) developed a fatal melanoma at one to seven years of age [32]. In all cases, the projected adult size of the nevus was >60 cm, and satellite nevi were present at birth. Melanomas arise less often within CMN restricted to the head or an extremity. No documented primary cutaneous melanomas developing within satellite nevi have been reported.

Neurocutaneous melanosis — Patients with CMN may rarely develop neurocutaneous melanosis, a proliferation of melanocytes in the central nervous system as well as the skin. Neurocutaneous melanosis encompasses both leptomeningeal melanosis and central nervous system melanosis [33]. (See "Uncommon brain tumors", section on 'Primary melanocytic lesions'.)

Neurocutaneous melanosis may be asymptomatic (noted on screening magnetic resonance imaging [MRI]) or symptomatic [34]. Symptomatic neurocutaneous melanosis is associated with a poor prognosis, with a high mortality rate in the first few years of life [35,36].

Risk factors — Risk factors for neurocutaneous melanosis include [34,37-40]:

A large CMN, especially if the predicted final size is >40 cm

Numerous satellite nevi

More than three medium-sized CMN (especially if many)

In a study of 379 patients with large CMN, of whom 26 (7 percent) had been diagnosed with neurocutaneous melanosis, those with >20 satellites had a fivefold increased risk for neurocutaneous melanosis compared with those with ≤20 satellites [40]. Neurocutaneous melanosis can also develop in patients with nevus of Ota. (See "Benign pigmented skin lesions other than melanocytic nevi (moles)", section on 'Nevus of Ota'.)

Clinical manifestations — Symptomatic neurocutaneous melanosis develops in approximately 3 to 10 percent of infants and children with high-risk CMN [38]. Clinical presentation occurs at a median age of two years, and prognosis is often poor even in the absence of malignancy [41]. Neurologic manifestations (eg, hydrocephalus, seizures) may result from intracranial hemorrhage, impaired cerebrospinal fluid circulation, spinal cord compression, or malignant transformation of the melanocytes [3,42].

Developmental delay and/or seizures have been reported in up to 15 to 25 percent of children with large or multiple CMN (some of whom did not have MRI evidence of neurocutaneous melanosis) [32,38,43].

Structural abnormalities of the central nervous system (eg, Dandy-Walker malformation/posterior fossa cysts), defects of the vertebrae or skull, and intraspinal lipomas occasionally occur in association with neurocutaneous melanosis [43]. (See "Prenatal diagnosis of CNS anomalies other than neural tube defects and ventriculomegaly", section on 'Dandy-Walker malformation'.)

Diagnosis — Neurocutaneous melanosis is best detected by MRI with gadolinium contrast [34]. For very young infants, it may be possible to obtain initial high-quality MRI images without general anesthesia using "feed and wrap" techniques that allow a swaddled infant to sleep during the MRI imaging procedure [44].

MRI of the brain and spine should be performed in any high-risk patient exhibiting neurologic symptoms. However, we also suggest that asymptomatic, high-risk patients be screened for neurocutaneous melanosis with gadolinium-enhanced MRI of the brain and spine (ideally during the first six months of life) before myelination, which may obscure evidence of melanosis [41].

Asymptomatic neurocutaneous melanosis is detected by MRI in 5 to 25 percent of infants and children with high-risk CMN [4,45]. In a five-year, follow-up study, only 1 of 10 patients with MRI findings suggestive of central nervous system melanosis progressed to develop neurologic symptoms [33].

Referral — Patients with high-risk CMN and neurologic symptoms or abnormal MRI findings should be referred to a pediatric neurologist for evaluation and monitoring. If the diagnosis of neurocutaneous melanosis is confirmed, repeat MRIs should be performed with the frequency guided by the degree of involvement and clinical findings [11].

Other malignancies — Other malignancies, such as rhabdomyosarcoma, liposarcoma, and malignant peripheral nerve sheath tumors, have been reported in the setting of large CMN [46].

MANAGEMENT — The available evidence on treatment of CMN is limited to case series and small, observational studies [47,48].

Small/medium-sized congenital melanocytic nevi — Small and medium-sized CMN are generally considered nonproblematic. These lesions are managed on an individual basis depending on factors that affect ease of monitoring (eg, color, thickness/topography, and location), clinical history, parents' or caregivers' anxiety, and cosmetic concerns [4].

As an example, a multinodular, black CMN on the scalp that is partially obscured by dense hair growth would be difficult to follow clinically, whereas a thin, light brown lesion on the face would be relatively simple to observe. However, the latter might be removed for cosmetic reasons, and the former may spontaneously lighten during childhood:

Clinical observation – Observation is an option for CMN of any size. Regular skin examination is most important after puberty, since the risk of melanoma arising within these lesions during childhood is extremely low. Baseline photographs can be helpful, and dermoscopy is a useful tool for assessing changes. (See "Dermoscopic evaluation of skin lesions".)

Patients and parents/caregivers should be instructed to perform home skin examinations, including palpation, of all nevi and to bring focal changes in color, border, or topography (eg, a red or black papule, nodule, or crust) or any new symptoms (eg, itching, burning, bleeding) to the clinician's attention. (See "Screening for melanoma in adults and adolescents", section on 'Patient self-examination'.)

Surgical excision – In many cases, surgical removal of small or medium-sized CMN is desired to improve the esthetic appearance [49]. Careful consideration of the anatomic location and the potential cosmetic and functional impairment resulting from excision and scarring is mandatory. For small CMN, some experts suggest one-step excision with direct wound closure if feasible. Excision may be performed at any point in time [49].

Laser therapy – Pigment-specific lasers (eg, 694 nm quality-switched [Q-switched] ruby laser, 755 nm Q-switched alexandrite laser) and ablative lasers (eg, 10,600 nm carbon dioxide [CO2] laser, 2940 nm erbium-doped yttrium aluminum garnet [Er:YAG] laser) have been used in small series of patients with small and medium-sized CMN with variable results [50-52]. Recurrence is common, and ablative lasers carry a risk for significant scarring. In one report, treatment with dual-wavelength copper vapor laser (511 and 578 nm wavelengths) demonstrated cosmetic improvement after two to three sessions in two adult patients with small CMN on the face [53].

Large/giant congenital melanocytic nevi — Given the relative rarity of large or giant CMN, there are no randomized trials evaluating the efficacy and outcomes of conservative or interventional approaches. The decision to treat and the possible surgical approaches should be discussed in a multidisciplinary team, including a pediatric dermatologist, plastic surgeon, and as needed, a neuroradiologist, neurologist, and oncologist [54,55]. A crucial point of the decision-making process, which should include parents and caregivers, is whether the lesion should be observed or treated surgically in the attempt to mitigate stigmatization and psychosocial consequences [49].

Observation versus surgery — In most cases, close clinical observation with no surgical removal of the lesion is a favored choice, but shared decision-making with parents or caregivers that focuses on achievable results with either approach is paramount [48].

In general, early surgical treatment of CMN, including dermabrasion and curettage in the neonatal period, has fallen out of favor. Close clinical observation with no surgical removal of the lesion is encouraged for large and giant CMN, unless worrisome clinical features suspicious of malignancy are present [48,55,56].

Reasons for avoiding surgery include the following:

There is no evidence that surgical interventions for large CMN reduce the risk of melanoma compared with nonintervention. In a series of 250 patients treated with excision, dermabrasion, laser, or combination treatment, two patients developed melanoma over a median follow-up period of nine years [55]. There are reports of melanoma occurring in adult patients who underwent dermabrasion or surgical excision of CMN during childhood [57,58].

Elimination of every nevus cell may be impossible because of the large area of skin affected, anatomic site (eg, distal extremity, periocular area, genitalia), and involvement of deeper structures (eg, fat, fascia, muscle). Even theoretically complete surgical excision cannot eliminate future risk of melanoma, as some melanomas may develop in the central nervous system or retroperitoneum in these patients.

Although the short-term cosmetic outcomes of dermabrasion or curettage in the neonatal period seem favorable, repigmentation and extensive scarring occur in most cases [49].

Many untreated CMN spontaneously lighten over time [55].

Surgical approaches — For large CMN for which surgical excision is advised or feasible, some experts suggest serial excisions at four- to eight-month intervals, starting at the age of six months, as the preferred treatment approach [49]. Advantages of serial excision include a single, linear scar (when the size of the nevus allows) without the need for skin grafts or large flaps.

Full-thickness skin grafts or skin expansion and advancement flaps may be needed for patients requiring multiple partial excisions. However, skin expansion is associated with a high rate of complications (eg, hematoma, infection, flap necrosis) requiring additional reconstruction [59,60].

Other surgical approaches, including curettage and dermabrasion in the neonatal period, are associated with adverse outcomes, including scarring and frequent pigment recurrence [48].

Regardless of the treatments employed, patients with large or giant CMN who have undergone surgical excision should be monitored for melanoma development with periodic skin and general physical examinations. Palpation of the residual nevus or scar areas is essential for the detection of focal indurations. Firm nodules or indurated areas should be biopsied and sent for histopathologic examination. (See 'Monitoring for melanoma' below.)

Even a theoretically complete removal of a large CMN does not eliminate the risk of melanoma, since melanoma of the central nervous system and other visceral primary sites (eg, the retroperitoneum) may still occur [61].

Monitoring for melanoma — Regular follow-up visits early in life with skin photography, when possible, are helpful to identify changes in CMN. Particularly in large or giant CMN, cutaneous melanomas can arise subepidermally, making early recognition difficult.

Palpation of the entire nevus surface for the detection of focal induration is an important part of the physical examination to try to detect deep nodules. In some patients with large or giant CMN, the site of the primary melanoma is the central nervous system or retroperitoneum, whereas others have no identifiable primary site.

Biopsy is recommended if the following changes are noted:

Firm or rapidly growing nodules

Ulcerated nodules

Amelanotic, atypically pigmented, or friable nodules

Focally painful or persistently itchy lesions

Irregular lesions, especially when crossing the border of the large of giant CMN or nevus excision scar

Surveillance for neurocutaneous melanosis — Patients with a large or giant CMN plus multiple (especially >20) satellite nevi or with multiple medium-sized CMN are at risk for neurocutaneous melanosis and should be followed with serial head circumference measurements, neurologic examinations, and developmental assessments [3,38,40]. This monitoring includes evaluation for signs and symptoms of increased intracranial pressure, mass lesions, and spinal cord compression [3,40].

Given the poor prognosis, aggressive surgical procedures for CMN removal in patients with symptomatic neurocutaneous melanosis should generally be avoided. However, neurocutaneous melanosis discovered on imaging in an asymptomatic patient does not necessarily preclude CMN excision surgery.

SPECKLED LENTIGINOUS NEVUS — Speckled lentiginous nevus (or nevus spilus) is a hyperpigmented, macular, patch-type, tan or light brown patch that contains superimposed, darker brown macules and papules (picture 16A-B). The "background" tan patch (café-au-lait macule-like) of a speckled lentiginous nevus is usually noted at birth or soon after, with round, pigmented macules and thin papules appearing within the lesion over time.

The superimposed, pigmented macules and papules can range from lentigines; to junctional, compound, and intradermal nevi; Spitz nevi; and blue nevi. There are two distinct subtypes of speckled lentiginous nevus: those with only macular speckles and those with papular and macular speckles [62].

Several lines of evidence suggest that speckled lentiginous nevi, which have a prevalence of approximately 2 percent, represent a subtype of CMN [63]. Some speckled lentiginous nevi have patterns of distribution reflecting embryonic development (eg, block-like with a sharp demarcation at the midline or following the lines of Blaschko).

The risk of developing melanoma in speckled lentiginous nevus is thought to be similar to classic CMN of the same size range. Speckled lentiginous nevus should be followed clinically with periodic examinations and biopsy of suspicious areas. (See 'Management' above and "Melanoma: Epidemiology and risk factors", section on 'Congenital nevi'.)

SUMMARY AND RECOMMENDATIONS

Epidemiology and classification – Congenital melanocytic nevi (CMN) occur in 1 to 3 percent of newborn infants; large or giant CMN occur in approximately 1 in 20,000 births (see 'Epidemiology' above). Based on the largest diameter that the nevus is projected to attain by adulthood, CMN are classified as follows (see 'Classification' above and 'Projected estimate of adult size' above):

Small – <1.5 cm (picture 1)

Medium-sized – M1 1.5 to 10 cm; M2 10 to 20 cm (picture 2)

Large – L1 >20 to 30 cm; L2 >30 to 40 cm (picture 3)

Giant – G1 >40 to 60 cm; G2 >60 cm

In a neonate, large CMN are >9 cm on the head or >6 cm on the body.

Clinical presentation – The color of CMN ranges from tan to black, and the borders are often geographic and irregular. Many CMN have an increased density of dark, coarse hairs (picture 3). Giant CMN are sometimes referred to as "garment" nevi, including "bathing trunk" nevi (picture 3) and bolero nevi, and are frequently accompanied by multiple smaller, widely disseminated "satellite" nevi. (See 'Clinical presentation' above.)

Natural history – CMN enlarge in proportion to the child's growth and undergo other age-related changes in pigmentation or surface characteristics. Many untreated CMN spontaneously lighten over time. Superimposed papules and nodules can develop, which occasionally require histologic examination to exclude the development of a cutaneous melanoma. (See 'Natural history' above and 'Proliferative nodules' above.)

Risk of melanoma – The risk of melanoma developing within a CMN is correlated with the nevus size. For small and medium-sized CMN, the risk is controversial but thought to be less than 1 percent over a lifetime. For large and giant CMN, the risk of cutaneous or extracutaneous melanoma is estimated to be approximately 2 to 5 percent over a lifetime. (See 'Risk of melanoma' above and "Melanoma: Epidemiology and risk factors", section on 'Congenital nevi'.)

Risk of neurocutaneous melanosis – Patients with CMN may have proliferation of melanocytes in the central nervous system (neurocutaneous melanosis) as well as the skin. Patients with either a large CMN accompanied by satellite nevi or multiple medium-sized CMN (≥3, usually numerous) are at risk of neurocutaneous melanosis. Neurocutaneous melanosis can be asymptomatic or may present with neurologic symptoms, such as hydrocephalus and seizures. (See 'Neurocutaneous melanosis' above.)

Management:

Small/medium-sized congenital melanocytic nevi – Small and medium-sized CMN are managed on an individual basis depending upon ease of monitoring, clinical history, parents' or caregivers' anxiety, and cosmetic concerns. (See 'Small/medium-sized congenital melanocytic nevi' above.)

Large/giant congenital melanocytic nevi – For large or giant CMN, clinical observation is a reasonable choice in most cases. When possible, surgical excision of large areas of nevus may require serial excisions, with or without tissue expanders, skin grafts, or advancement flaps. The timing of surgery and the surgical techniques are based upon size, location, and anesthesia options. (See 'Large/giant congenital melanocytic nevi' above.)

Surveillance for melanoma and neurocutaneous melanosis – Regular follow-up visits early in life with serial skin photography, when possible, are helpful to identify changes in CMN. A biopsy is warranted for any changes suspicious of melanoma (eg, a nodule that is growing rapidly or is ulcerated or amelanotic). Patients with large/giant CMN at risk for neurocutaneous melanosis should be screened with gadolinium-enhanced MRI of the brain and spine during the first six months of life. (See 'Monitoring for melanoma' above and 'Surveillance for neurocutaneous melanosis' above.)

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Topic 4847 Version 14.0

References

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