Observation is appropriate for the majority of lesions. If treatment is desired for aesthetic reasons, symptoms, or malignancy concerns, full thickness excision is the treatment of choice. For most lesions it is recommended that excision be carried down to the fascia. For larger lesions this may require serial excisions, skin grafts, or the use of tissue expanders. See Table 9.2.

Laser therapy may be an option to improve cosmesis in lesions not amenable to surgical excision. Various lasers, both pigment specific and nonselective, have been used with widely variable efficacy, ranging from poor to excellent. Scarring and dyspigmentation are potential complications and recurrence is very common. Multiple treatment sessions are necessary. There is some concern that laser treatment of CMN may mask the development or even increase the risk of melanoma, but this has not been proven in studies [6–8].

Curettage and dermabrasion have been advocated as procedures to remove the superficial portion of CMN, thereby lightening the lesion and decreasing the nevus cell burden. Results have been variable. Both of these procedures are done in the newborn period to take advantage of the natural cleavage plane between the epidermis and dermis. Recurrence and hypertrophic scarring are potential complications. There is some concern that the scarring induced by these procedures may mask the detection of melanoma (Table 9.3).

Spitz tumors are diagnosed based on clinical and/or histologic features. Ancillary immunohistochemical and genetic studies exist though without the sensitivity or specificity necessary to distinguish atypical Spitz tumors from melanoma.

Lesions without atypical features should be monitored every 3–12 months. Patients should return if the lesion changes appearance. Lesions concerning for atypical Spitz tumors or melanoma should be removed by simple excision with margins of 3–5 mm (Table 9.4). Atypical Spitz tumors with positive margins should be re-excised with clear margins of 1 cm if cosmetically feasible. Severely atypical Spitz tumors should be managed as melanomas. Sentinel lymph node biopsy in the case of atypical Spitz tumors is controversial, as there is no data to suggest this improves prognosis (Table 9.5).

A halo nevus is a melanocytic nevus surrounded by a zone of depigmentation, often resulting in spontaneous regression of the nevus [22]. This halo phenomenon is most often associated with acquired benign melanocytic nevi, but has been reported to occur around congenital nevi (Fig. 9.3), Spitz nevi, blue nevi, and melanoma. Halo nevi can be single or multiple, and most frequently occur on the trunk. They are common in children and young adults, with an estimated prevalence of 1 %; but occur at higher rates in patients with vitiligo and Turner syndrome [23, 24].

The diagnosis is usually evident clinically. Dermatoscopic examination most commonly shows a globular and/or homogeneous pattern encircled by a white structureless area [25]. Histological examination shows a dense, often band-like, infiltrate of lymphocytes in the papillary dermis intermingled with nests of nevus cells.

Because the majority of halo nevi in children are benign and typically regress over months to years, observation of halo nevi is usually sufficient [22, 26]. If the central nevus is atypical or the halo is asymmetrical, a biopsy of the nevus is indicated.

Observation is generally sufficient for halo nevi. Most are benign and spontaneously regress over time. If the central nevus or surrounding halo has any concerning features, a biopsy is indicated and further treatment is based on the histological findings. See Table 9.7.

Becker’s melanosis (also known as Becker’s nevus) is a cutaneous hamartoma which often develops in the peripubertal period, although has been noted in some cases to be present at birth [27]. Clinically, this benign hamartoma is typically hyperpigmented and unilateral with an irregular border and surface (Fig. 9.4). Common locations are the shoulders, scapula or anterior chest. In many cases increased overlying hair and/or acne are present. The hypertrichosis and acne tend to be more prominent in males because of androgen mediated effects [28]. Becker’s nevus syndrome has been described which is characterized by associated abnormalities including breast hypoplasia, limb asymmetry, scoliosis, and supernumerary nipples [29].

Observation is the primary approach to the lesions. Excision of overgrowths may be recommended if they are symptomatic. See Tables 9.8 and 9.9 for management options.

Nevus comedonicus is a hamartoma involving the pilosebaceous unit. It consists of grouped dilated follicular openings containing central keratotic plugs, resembling open comedones. Pustules, cysts, abscesses, secondary bacterial infection and scarring can occur. Lesions can be localized or extensive.

Nevus comedonicus syndrome refers to a neurocutaneous disorder that consists of nevus comedonicus with associated skeletal (scoliosis, fused vertebrae, spina bifida), ocular (cataracts), limb defects (absent fifth finger, polydactyly), or neurological abnormalities [31].

A variety of benign epithelial tumors, including trichoepithelioma, syringocystadenoma papilliferum, hidradenoma papilliferum, and keratoacanthoma, have been reported to occur in nevus comedonicus. Malignant tumors are rare, but basal cell and squamous cell carcinoma have been reported [32].

The diagnosis is usually evident clinically. Histological examination shows hairless dilated follicular ostia filled with lamellar keratin, epidermal invaginations, rudimentary sebaceous glands, and absent arrector pili muscles.

Nevus comedonicus is a benign lesion, therefore treatment is not required, unless desired for aesthetic purposes or for lesions complicated by recurrent inflammation and/or infection. The only definitive treatment is surgical excision. Numerous medical and surgical treatments have been reported, with incomplete responses. The treatment of extensive lesions is very challenging and often disappointing.

Complete surgical excision is curative and is the treatment of choice for lesions that are bothersome and amenable to surgical excision. Various topical therapies, including emollients, topical keratolytics (ammonium lactate 12 %, salicyclic acid), topical retinoids (tretinoin, tazarotene), topical vitamin D analogs (calcipotriene, talcalcitol), alone or in combination may improve cosmesis in some patients [31–33]. Commercial pore remover strips may be helpful for removing keratin plugs [34]. Inflammatory lesions may respond to treatment with topical or intralesional corticosteroids. Oral antibiotics are indicated if secondary infection is present. Incision and drainage or excision of localized abscesses or cysts is effective (See Table 9.11) [35].

Laser treatment with various lasers, including 1,450 nm diode laser, ultrapulsed CO₂ laser, and erbium:YAG laser, have been reported to be effective in adults. Laser therapy can be considered for bothersome lesions not amenable to surgical excision or for extensive lesions [36, 37].

Isotretinoin has been reported to be helpful for decreasing the number of cystic flares associated with inflammatory lesions, but has not been effective as a therapy for non-inflamed lesions (Table 9.12) [34].

Dermabrasion, shave excision, and manual comedone extraction have poor efficacy and often produce unacceptable scarring and recurrence (Table 9.13).

Nevus sebaceous (NS) is a hamartoma of the pilosebaceous unit. NS occurs in approximately 0.3 % of newborns and is usually evident at birth as an oval or linear, hairless, yellow-brown plaque on the scalp (Fig. 9.5a) or less frequently on the face and neck. At puberty, NS becomes more papillomatous or verrucous, due in part to androgen stimulation of the aberrant sebaceous glands (Fig. 9.5b).

It is estimated that approximately 20 % of lesions will develop secondary, mostly benign, tumors. The most common tumor is trichoblastoma, followed by syringocystadenoma papilliferum. Basal cell carcinoma is estimated to occur in approximately 1 % of lesions and is extremely unlikely to appear before puberty. Squamous cell carcinoma, adenocarcinoma, and sebaceous carcinoma have also been reported [38–40].

Nevus sebaceous syndrome (Schimmelpenning syndrome) refers to the association of an extensive linear nevus sebaceous that follows the lines of Blaschko with neurological (seizures, developmental delay, hemimegalencephaly), ocular (lipodermoid, coloboma), and skeletal (skull deformity, scoliosis, short stature) anomalies. Patients with nevus sebaceous syndrome are also at risk for Vitamin D-resistant hypophosphatemic rickets, which should be suspected in patients with an extensive nevus sebaceous along with growth retardation, bone pain, fractures or bone deformities [41].

The diagnosis of nevus sebaceous can usually be made clinically. A biopsy can be done if the diagnosis is uncertain. In prepubertal children, histopathology reveals mild epidermal acanthosis and papillomatosis with immature sebaceous glands and pilosebaceous units. After puberty, there is more prominent acanthosis and papillomatosis of the epidermis, prominent sebaceous glands often located high in the dermis, immature hair follicles and ectopic apocrine glands in the lower dermis.

Historically, excision prior to puberty was recommended due to the perceived high rate of basal cell carcinoma. Given that the rate of malignant transformation is actually quite low, especially in children, prophylactic excision of all lesions before puberty is no longer recommended. However, lesions should be observed for suspicious changes, and new localized growths or ulceration should be biopsied and completely excised if necessary. Prophylactic removal may be desirable in some cases for cosmetic concerns, and the timing of such excision should be evaluated on an individual basis.

Full thickness excision, when feasible, with 2–3 mm margins, is the treatment of choice for lesions that are symptomatic or cosmetically concerning. Staged excision or tissue expansion can be done if necessary. The timing of excision is dependent on the age of the child, size and location of the lesion, and the risks and benefits of general anesthesia versus local anesthesia later in life (see Table 9.15) [40].

Nonsurgical options for the treatment of NS include photodynamic therapy and various lasers. These treatments produce variable results and should be reserved for extensive lesions or lesions not amenable to surgical excision. Photodynamic therapy using various photosensitizers (aminolevulinic acid 20 % or methylaminolevulinate) and light sources (light emitting diodes device, 630-nm argon tunable dye laser, intense pulsed light), have resulted in cosmetic improvement in a small number of patients with facial NS. Laser ablation or curettage of thicker lesions or nodules was done prior to photodynamic therapy in some patients [42, 43]. Different lasers, including continuous wave CO₂ laser, fractional CO₂ laser, and erbium:YAG laser, have been reported to be useful in single case reports [40, 44]. Multiple treatment sessions were necessary for all of these modalities (Table 9.16). It is important to realize that these modalities do not completely remove the lesion, leaving a risk for recurrence and development of secondary neoplasms; therefore continued monitoring is necessary.

Adnexal tumors are a diverse group of benign neoplasms originating from adnexal epithelium. The most common adnexal tumors in children include pilomatricomas, trichoepitheliomas, and syringomas [45]. These tumors are often solitary, but can be multiple, especially when associated with an underlying syndrome (Table 9.17).

Pilomatricomas are most common on the head and extremities and present as hard, mobile subcutaneous nodules, often with a pink or blue hue. Due to calcification in the tumor, they may show a “teeter-totter” sign or “tent” sign when the overlying skin is stretched. Trichoepitheliomas appear as skin-colored papules with a predilection for the central face. Syringomas present as small, yellow-white translucent papules most commonly on the lower eyelids, neck, upper chest and genitalia (Fig. 9.6). They may occur in an eruptive manner. The clinical presentation of other adnexal tumors is summarized in Table 9.18.

Adnexal tumors are benign and therefore treatment is not necessary, but may be desired for aesthetic or symptomatic reasons. Solitary lesions are best treated by surgical excision.

Treatment of multiple adnexal tumors is often difficult, but electrodessication, electrosurgery, cryosurgery, dermabrasion, chemical peels and laser ablation have been reported with variable success.

Surgical excision is the treatment of choice for isolated lesions. The recurrence rate after complete excision is extremely low (Table 9.19) [46].

Laser ablation using various CO₂ lasers (continuous wave, pulsed, fractional) or erbium:YAG has been reported for patients with multiple syringomas or trichoepitheliomas (see Table 9.20). Several treatment sessions may be necessary, and recurrence and scarring are potential complications [47]. Other destructive methods have also been reported in small numbers of patients.

Mastocytosis is characterized by infiltration of mast cells in the dermis. Maculopapular cutaneous mastocytosis lesions (MPCM) have a “peau d’orange” clinical appearance (Fig. 9.7). The lesions urticate and become reddened with rubbing (positive Darier’s sign) and some may become vesicular. Cutaneous lesions of mastocytosis may present as: (1) a single lesion (Solitary mastocytoma); (2) multiple maculopapular lesions (maculopapular cutaneous mastocytosis-MPCM aka Urticaria pigmentosa); or (3) diffuse infiltrative lesions [48].

The lesions are often present before 2 years of age and may affect any area of the body. Spontaneous resolution of hyperpigmentaiton is often seen by 10–12 years of age, although urticarial changes are usually difficult to elicit after 4 years of age [49].

Familial mastocytosis are rare, with fewer than 100 cases reported in the literature [50]. Individual lesions are clinically similar between different subtypes of cutaneous mastocytosis, however, familiar mastocytosis often persist into adulthood. Over 90 % of patients with mastocytosis have mutations of the c–kit gene that often occur spontaneously. Mutations have been found on exons 8, 9, 10, 11, 13, 17, and 18 of c–kit.

Childhood-onset mastocytosis has a better prognosis than adult-onset disease and has less systemic involvement that is mastocytosis related [48].

Basal cell nevus syndrome (BCNS; also known as Gorlin syndrome) is an autosomal dominant multi-system disorder caused by mutations in the PTCH1 gene. The main features are: (1) multiple basal cell carcinomas (BCCs); (2) odontogenic keratocysts of the jaw; (3) palmar/plantar pits; (4) skeletal abnormalities (most commonly of the ribs and spine); (5) ectopic calcification of the falx cerebri; (6) ocular abnormalities; and (7) medulloblastoma. Macrocephaly and typical facial features, including frontal bossing and hypertelorism, are frequent and early findings. Young children often have multiple facial milia and skin lesions that resemble nevi (“basal cell nevi”) or skin tags, but with the typical histological appearance of BCC (Fig. 9.8) [56]. These lesions generally lack aggressive behavior in childhood. Invasive BCC usually presents during late teens and early adulthood and becomes more frequent with age. Crusting, ulceration, and enlargement are signs of invasion. The diagnosis of a BCC before the age of 20 should signal an evaluation for BCNS.

The management of BCNS requires a multidisciplinary and individualized approach, which entails appropriate surveillance for complications, minimizing exposure to radiation, treatment of tumors, and genetic counseling. Several surgical and nonsurgical options exist for the treatment of BCCs. Often a combination of treatment modalities is necessary and the choice of treatment is dependent on many factors, including the age of the patient, location, size and number of BCCs, as well as the histological subtype. Aggressive treatment of BCCs in younger children may not be necessary, as most of these lesions will not become invasive. The optimal treatment of BCCs in patients with BCNS remains to be defined.

Exposure to radiation should be minimized as much as possible as soon as the diagnosis is suspected. Approximately 5–10 % of children develop medulloblastoma and treatment with radiation therapy should be avoided, if feasible, because of the high numbers of BCCs that may develop in the field of radiation. All patients should be counseled on the importance of strict sun protection. This involves the use of protective clothing and glasses, SPF 30+ sunscreens, and avoidance of sun during midday hours. Radiographs should be minimized as much as possible and performed only as needed for diagnosis or management of valid medical issues.