Proliferative nodules of undifferentiated spindle cells arising in a large congenital melanocytic naevus

Proliferative nodules (PN) are benign lesions that arise in large congenital melanocytic naevi (LCMN). Clinically and histologically they can be difficult to differentiate from malignancies, which are also associated with LCMN. The PN in this case consisted of undifferentiated spindle cells and exhibited unusual histological features including negative stains for melanocytic markers (S100, HMB45 and MelA), negative stain for c‐Kit, high mitotic index and unusual morphology of the lesional cells. As a result, a firm histological classification could not be made, which posed a challenge for the clinical management.     

Clinical characteristics and risks of large congenital melanocytic naevi: A review of 31 patients at the Sydney Children's Hospital

Large congenital melanocytic naevi (LCMN) are associated with an increased risk of malignancy and neurocutaneous melanocytosis (NCM). This Australian study aims to assess both the clinical characteristics of LCMN and the risks associated with it. The authors reviewed medical records of the Sydney Children's Hospital Dermatology Outpatient Clinic for the past 10 years and identified 31 eligible patients. A total of 14 boys and 17 girls with a median age of 0.13 years were assessed; 18 lesions were on the trunk, five were on the head, five were on the lower limbs and three were on the upper limbs. In all 20 patients had satellite naevi (the median number of the satellite naevi was 7.5). The patients were followed up for a median duration of 12 months. Central nervous system magnetic resonance imaging was performed on 19 patients and two (6.5%) were found to have NCM. Biopsies were performed on five patients; one patient (3.2%) was found to have benign proliferative nodules of undifferentiated spindle cells but no patient (0%) was found to have a malignancy. The clinical characteristics for the two patients with NCM and the patient with benign proliferative nodules suggest that the risk of both NCM and benign proliferative nodules may be greater with an increased number of satellite naevi and with the LCMN being larger in size.     

Distinct phenotypic changes between the superficial and deep component of giant congenital melanocytic naevi: a rationale for curettage

BACKGROUND: Giant congenital melanocytic naevi (GCMN) convey a 14-fold increased melanoma risk. In contrast, medium congenital melanocytic naevi (MCMN) are rarely associated with malignant transformation. Management of patients with GCMN is challenging and there is no consensus on the most appropriate strategy for treating these patients. OBJECTIVES: To provide a rationale for performing curettage of GCMN in the neonatal period in order to reduce the risk of malignant transformation to melanoma. METHODS: Twenty-six infants with GCMN who underwent biopsies before excisional surgery (n = 7) or curettage (n = 19) during the past 14 years (Academic Hospital, Vrije Universiteit Brussel) and 10 MCMN patients who underwent excision biopsies (Radboud University Nijmegen Medical Centre) were included in this study. Using these biopsies, we performed genetic and detailed immunohistochemical evaluations of changes that are associated with malignant transformation. Variables of interest included melanoma-associated BRAF mutations, proliferative activity, vascularity, cellular context and extracellular matrix architecture. RESULTS: GCMN and MCMN did not show oncogenic BRAF mutation and displayed similar features with respect to the amount of nonmelanocytic cells within the naevus and matrix architecture. Naevus cells in the superficial component of the GCMN, however, were more proliferative, and this component was more vascular compared with its deep component and with MCMN. In this study, none of the 19 newborn patients who underwent curettage developed a melanoma within a mean follow-up time of 7 years. CONCLUSIONS: The data presented here support the idea that curettage of GCMN in neonates has the potential for lowering the risk of developing cutaneous melanoma by not only obtaining an important numerical reduction of naevus cells but also removing the 'active' melanocytes.     

Association of melanoma and neurocutaneous melanocytosis with large congenital melanocytic naevi--results from the NYU-LCMN registry

BACKGROUND: Large congenital melanocytic naevi (LCMN), which develop in utero and are present in approximately one in 20,000 newborns, are associated with markedly increased risks of cutaneous melanoma, leptomeningeal melanoma and neurocutaneous melanocytosis (NCM). OBJECTIVES: This study examined clinical characteristics associated with melanoma and NCM among patients with LCMN, and estimated the risk of developing melanoma and NCM in these patients. METHODS: Two hundred and five LCMN patients enrolled in the New York University registry were studied. One hundred and seventy of these patients were followed prospectively. The remaining 35 patients had either melanoma at the time of entry into the registry (n = 6), or had insufficient follow-up information (n = 29). The outcome measures were the occurrence of melanoma and NCM. The associations between these outcomes and the clinical covariates (anatomical location of the LCMN, size of the LCMN, number of satellite lesions, family history of melanoma, patient sex and treatment) were assessed. RESULTS: Four of 170 (2.3%) prospectively followed patients developed melanomas, representing a standardized morbidity ratio of 324. Among the entire cohort (n = 205), there were associations between increasing numbers of satellite naevi and the occurrence of melanoma (P = 0.04), and the presence of NCM (P = 0.06). Compared with patients who did not develop these diseases, median LCMN diameters were larger among patients who developed melanoma (49 vs. 39 cm) and NCM (55 vs. 46 cm). CONCLUSIONS: In LCMN patients, increasing numbers of satellite lesions and larger LCMN diameters are associated with melanoma and NCM.     

Melanoma risk in congenital melanocytic naevi: a systematic review

BACKGROUND: The risk of malignant melanoma in congenital melanocytic naevi (CMN) is a matter of controversial and ongoing debate. OBJECTIVES: The purpose of this systematic review is to provide a careful and detailed summary of the published data, including several recently published studies. METHODS: Articles on CMN (n=1424) were retrieved from Medline, 1966-October 2005. Case reports and studies lacking relevant clinical information were excluded. Only systematic collections of cases were taken into consideration. Series with fewer than 20 patients or studies with a mean follow-up of <3 years were regarded as epidemiologically less significant. RESULTS: Fourteen articles were finally chosen for further analysis. The studies varied significantly with respect to study design (source of cases; retrospective vs. prospective analysis), age of patients, follow-up time, and naevus characteristics. The frequency of melanomas ranged between 0.05% and 10.7% and was significantly higher in smaller studies (P<0.0001). In a total of 6571 patients with CMN who were followed for a mean of 3.4-23.7 years, 46 patients (0.7%) developed 49 melanomas. The mean age at diagnosis of melanoma was 15.5 years (median 7). By comparison with age-adjusted data from the Surveillance, Epidemiology and End Results database, we calculated that patients with CMN carry an approximately 465-fold increased relative risk of developing melanoma during childhood and adolescence. Primary melanomas arose inside the naevi in 33 of 49 cases (67%). In seven cases (14%), metastatic melanoma with unknown primary was encountered; in four cases (8%) the melanoma developed at an extracutaneous site. The risk of developing melanoma and the rate of fatal courses were by far highest in CMN>or=40 cm in diameter. CONCLUSIONS: The overall risk of melanoma of 0.7% in all 14 studies was lower than expected. The higher incidence of melanomas in smaller studies indicates selection bias. The melanoma risk strongly depends on the size of CMN and is highest in those naevi traditionally designated as garment naevi. The median age of 7 years at diagnosis of melanoma points to a risk maximum in childhood and adolescence. Future studies on CMN should report: (i) diameter, percentage of body surface, and localization of the CMN; (ii) percentage of naevus area removed by excision or subject to dermabrasion or other superficial treatments; (iii) mean and median age at entry into the study; (iv) mean and median follow-up time; (v) details on each melanoma case; (vi) standardized morbidity ratio of melanoma; and (vii) percentage of neurocutaneous melanosis.     

Desmoplastic hairless hypopigmented naevus: a variant of giant congenital melanocytic naevus

Desmoplasia has been described in melanoma and Spitz naevus but not in giant congenital melanocytic naevus (GCMN). In melanoma desmoplasia is associated with a better survival. Four paediatric patients with hard, ligneous, progressively hypopigmented and alopecic GCMN were seen among 143 cases of GCMN at the Department of Dermatology of the National Institute of Paediatrics, Mexico City. Clinically, induration was progressive in three patients and regressive in one. Pigmentation was regressive in all. Histopathologically, all four patients showed intense dermal fibrosis, scarce naevus cells, and hypotrophic or absent hair follicles. Follow-up and serial biopsies in three patients documented the progressive nature of fibrosis and naevus cell depletion. No evidence of malignant transformation was found. Naevus cell depletion resulted in pigment loss and may have reduced the risk of malignant transformation. Although the cause of fibrosis is unknown, the possibility of an immune reaction to naevus cells is postulated.     

Congenital melanocytic nevi needing treatment

Patients presenting with congenital melanocytic nevi (CMN) need individualized treatment based upon nevus size, thickness, location, risk for developing melanoma, and psychological characteristics of the patient and family. The present authors review CMN types and prognoses, as well as absolute and relative indications for treatment. Risks and benefits of several treatment options are discussed, including surgical options, such as excision, chemical peels, dermabrasion and curettage, and laser therapy. The main focus of treatment is, in all cases, to address the concern for developing melanoma, at the same time optimizing the aesthetic and functional outcomes.     

Frequency and distribution pattern of melanocytic naevi in Estonian children and the influence of atopic dermatitis

BACKGROUND: There is a strong correlation between naevus number and prospective melanoma risk. Melanoma is one of the most rapidly increasing cancers in Estonia and primary prevention programmes for melanoma that target risk behaviour in the sun have so far not been launched. METHODS: The naevus profile was examined in 549/700 9-year-old Estonian children (282 boys and 267 girls) and the presence of active atopic dermatitis (AD) was registered. RESULTS: There was a wide range of naevi (4-121) and a median total body count of 26. There was no difference in naevus count between boys and girls. No dysplastic naevi were found. Thirty-nine of 549 children (7%) had at least one lesion clinically diagnosed as a congenital naevus. Boys had more naevi on the face (median 4) and trunk (median 12) than girls (median 3 and 9, respectively, P < 0.001). Girls had more naevi on the legs compared with boys (median 4 and 3, respectively, P < 0.01). Fifty-four out of 549 (9.8%) had naevi on the palms and 18/549 (3.3%) on the soles. Children with fair skin, freckles and light hair and eye colours had significantly more naevi than those with darker colours. Thirty-one of 549 (6%) children had AD diagnosed on the examination day and they had a lower total naevus count (median 20) compared with children with no AD (median 27, n = 518, P < 0.05). CONCLUSIONS: The naevus situation in Estonian children today might constitute a starting point for evaluating the efficiency of coming preventive measures as a change of naevus number in children might serve as an early marker for a change in melanoma incidence.     

Distribution of congenital melanocytic naevi and congenital naevus-like naevi in a survey of 3406 Italian schoolchildren

Background  Scanty information is available on the prevalence of congenital melanocytic naevi (CMN) and congenital naevus-like naevi (CNLN), particularly the small ones.
Objectives  To estimate the prevalence of CMN/CNLN in Italian schoolchildren, and to assess variations according to potential risk factors for melanoma.
Methods  We conducted a survey in 13 Italian areas on 3406 schoolchildren aged 12–17 years. Children were examined by dermatologists who assessed pigmentary traits and made a count of small (6–15 mm in diameter) and medium/large (> 15 mm) CMN/CNLN on 19 anatomical areas.
Results  Overall, 592 children (17·4%) had one or more CMN/CNLN. Prevalence of small CMN/CNLN was 16·1%, and that of medium/large CMN/CNLN was 1·8%. There was no difference between age groups and sexes. CMN/CNLN were more frequent in children with a higher number of common melanocytic naevi (multivariate odds ratio, OR = 7·1 for the highest vs. the lowest quartile), consistent in small (OR = 7·2) and medium/large CMN/CNLN (OR = 6·0). Family history of malignant melanoma (OR = 1·4) and personal history of diabetes (OR = 4·4) appeared to be directly, and sun exposure inversely associated with CMN/CNLN. No relation was evident between CMN/CNLN and pigmentary traits, anthropometric characteristics, dietary habits, freckles, sunburns, sunscreen use or history of selected diseases.
Conclusions  The association with family history of melanoma, the strong association with acquired melanocytic naevi, and the lack of association with pigmentary traits and sunburns suggest that CMN/CNLN may act as an independent risk marker for subjects at increased risk for cutaneous melanoma later in life.     

Spitz naevi misdiagnosed histologically as melanoma: Prevalence and clinical profile

A Spitz naevus is a benign melanocytic tumour that may histologically resemble a malignant melanoma. Data was retrospectively gathered from patients who attended the Victorian Melanoma Service to determine the prevalence of Spitz naevi pathologically misdiagnosed as melanoma. Assessment of the clinical characteristics of these patients was also performed and compared to those with correctly diagnosed melanoma. It was found that 6.5% of all melanomas referred were in fact Spitz naevi and that Spitz naevi represented the majority of pathologically misdiagnosed melanomas. The Spitz naevi were more likely to be on the lower extremities and were on average, considerably smaller than the melanomas. Patients with Spitz naevi were more likely to be younger, female, have fewer dysplastic naevi and have brown eyes. One hundred per cent of the Spitz naevi were brought to the attention of the initial doctor by the patient compared to 72% of the melanomas. This study concludes that Spitz naevi that are pathologically misdiagnosed as melanomas retain the clinical characteristics of other Spitz naevi and mat greater clinicopathological communication may reduce the frequency of diagnostic error.     

Proposal of a new classification system for melanocytic naevi

The lack of consensus among clinicians and pathologists due to the mixture of clinical and histopathological features used to define the various melanocytic naevi underscores the need of a better classification system for these benign lesions. We describe a dermoscopic classification system for melanocytic naevi that is directed to clinicians dealing with the early diagnosis of melanoma, as well to pathologists, in order to promote better communication between these different specialists.     

Benign melanocytic proliferative nodule within a congenital naevus

A neonate presented with a deeply pigmented papule within a medium-sized congenital naevus. Histologically, this proved to be a benign proliferative nodule in a congenital naevus. This case is presented to highlight the occurrence of this lesion, the main differential of which is the rare entity of true congenital melanoma.     

Surgical approach to benign small papular and dome-shaped melanocytic naevi on the face

Patients frequently request removal of benign papular and dome-shaped naevi for cosmetic or functional reasons. Melanocytic naevi can be removed by elliptical, round, punch or shave excision or destroyed using electrodessication or cryotherapy. Total elliptical excision is probably the most widely used method of removal. If malignancy is suspected, adequate specimens for histological interpretation are required. When malignancy is not suspected, the cosmetic result becomes the first priority. Smaller incisions minimize tissue trauma and so give cosmetically superior results. Round excision has been recommended for the removal of moles but has not been widely practised. Round excision and punch excision may be better alternatives than conventional fusiform excision of benign dome-shaped or papular naevi of the face, as more tissue is preserved. Shave excision of naevi may be preferable to elliptical excision in sites where the incidence of hypertrophic scarring is high, as preservation of some thickness of the dermis may result in a more acceptable scar or even avoid a scar entirely. Expedient and simple surgery with excellent cosmetic results can be accomplished by the use of punches. Cryotherapy with cutting or curetting and electrodesiccation combined with shaving have been described. Round excision may be a better alternative to conventional fusiform or shave excision of benign papular or dome-shape nevus of the face because it leaves an almost imperceptible scar. In this technique, less skin is excised and histopathological examination can be done.     

Clinically equivocal melanocytic skin lesions with features of regression: a dermoscopic-pathological study

BACKGROUND: Benign melanocytic skin lesions may be difficult to differentiate from melanoma both clinically and dermoscopically. One of the most confounding dermoscopic features, commonly seen in melanoma but in our experience also in melanocytic naevi, is represented by the so-called blue-white structures (BWS). OBJECTIVES: To evaluate diagnostic significance and histopathological correlates of BWS seen by dermoscopy in a series of clinically equivocal melanocytic skin lesions that were excised. METHODS: Patients were recruited from six specialized pigmented lesion clinics in Austria, Italy and Spain over a period of 9 months. All consecutive patients showing one or more melanocytic lesions with BWS, but not classified as melanoma dermoscopically, were included. Each lesion was photographed clinically and dermoscopically. All images were reviewed by one of us and the degree, type and location of BWS evaluated for each lesion. A panel of four experienced dermatopathologists independently reviewed all specimens for diagnosis and one of them evaluated presence and degree of melanosis and/or fibrosis. The main outcome measures were the percentage and histopathological correlates of lesions with different degree, type and location of BWS. RESULTS: All included lesions with BWS (n = 158) showed partial or focal regression histopathologically. One hundred and thirty-five (85.4%) lesions were diagnosed as melanocytic naevi (complete histopathological interobserver agreement), whereas 23 (14.6%) were defined as equivocal because at least one of four pathologists diagnosed the given lesion as melanoma. Only one lesion was diagnosed as melanoma by all four pathologists. The majority of naevi exhibited blue areas (84.4%) with a central distribution (57%) and involving < 50% of the lesion surface (89.6%). By contrast, 78.3% of equivocal lesions revealed a combination of white and blue areas with an irregular distribution (60.9%) and involving > 50% of the lesion surface (47.8%). CONCLUSIONS: Using degree and type of BWS, an algorithm was constructed that can be applied for the management of lesions exhibiting dermoscopic features of regression.     

Treatment of acquired junctional melanocytic naevi by Q-switched and normal mode ruby laser

BACKGROUND: Acquired junctional melanocytic naevi are harmless pigmented lesions of the epidermis, which can be of cosmetic concern. Various therapeutic approaches have been used in the treatment, but all these methods produce postoperative scarring or alterations in skin texture. Pigment laser treatment of benign pigmented lesions has shown a low potential for scarring by selectively targeting melanosomes in melanocytes and keratinocytes. OBJECTIVE: To find a fast, effective and safe treatment for the removal of acquired junctional melanocytic naevi. PATIENTS/METHODS: We first studied the effect of the Q-switched and normal mode ruby laser on 12 patients (eight women and four men) with acquired melanocytic naevi. The effect was monitored by histology and clinical photography. RESULTS: If the response to one treatment with the Q-switched laser mode was not completely effective, the lesions were subsequently treated with one or two sessions with the laser in normal mode. All flat lesions responded completely. After a follow-up period of 1 year they had not recurred. Slightly elevated lesions showed only a partial response, e.g. disappearance of the junctional part of the naevus but recurrence of the dermal part of the naevus. Red-brown junctional naevi as seen in skin types I and II did not respond well to ruby laser treatment. CONCLUSIONS: The Q-switched ruby laser was very successful in completely removing flat (non-palpable) acquired junctional melanocytic naevi, but not compound naevi, with one to three treatment sessions, without any scarring or pigmentary disturbance.     

Atopic dermatitis and melanocytic naevi

A study was performed to test the clinical impression that adults with severe atopic dermatitis (AD) have a low number of common naevi (CN). The number of CN > or = 2 mm was investigated in 51 Caucasian patients aged 20-63 years with severe AD since early childhood. The control group consisted of 379 randomly selected subjects, aged 30-50 years, investigated in an earlier study. Patients with AD had a significantly (P < 0.0001) lower total body count of CN (mean 9, median 5) compared with the control group (mean 67, median 53). It was also found that in the AD group there was a significant (P < 0.001) negative correlation between serum IgE and number of CN [r(s) = -0.50, 95% CI (-0.69; -0.24)]. The explanation for the low number of naevi that we have found in this highly selected subgroup of AD patients is not known. The atopic inflammation in the skin, genetics and treatment used for eczema are possible factors that may influence the formation of melanocytic naevi.     

The prevalence of melanocytic naevi among schoolchildren in South Hungary

Background Malignant melanoma is an increasing public health problem worldwide; accordingly, identification of the constitutional and environmental factors which contribute to the development of the disease, and hence identification of the individuals at high risk of melanoma, is an indispensable step in all primary prevention efforts. Objectives This paper aims to assess the prevalence of different pigmented lesions among schoolchildren and to investigate their relationship with phenotypic pigmentary characteristics, sun exposure and other factors. Patients/methods A cross‐sectional study was performed in two secondary schools in Szeged, Hungary. A total of 1320 schoolchildren, aged 14 to 18 years, underwent a whole‐body skin examination. A standardized questionnaire was used to collect data on phenotypic, sun exposure and other variables. Results One to 10 common melanocytic naevi were found in 27% of the participants, and the naevus numbers were in the range of 10–100 in 67%; 5.4% of them had more than 100 common melanocytic naevi. The prevalence of clinically atypical naevi was 24.3%. Statistically significant associations were found between the number of pigmented lesions and gender, hair colour, eye colour, skin phototype, a history of severe painful sunburns and a family history of a large number of melanocytic naevi. Conclusion Our study population displayed a markedly high prevalence of clinically atypical melanocytic naevi. Moreover, a considerable proportion of the investigated individuals had multiple common melanocytic naevi. Since the presence of a large number of melanocytic naevi is a strong predictor for future melanoma development, health educational programmes on melanoma prevention should be aimed at young age groups.