Common Naevi Research Articles

Differential Immunoexpression of BRAF/V600E, Senescence Markers, PTEN, and T-type Calcium Channels in Acquired Naevi According to their Histopathological and Dermoscopic Classification.

BRAF/V600E mutation and other cell growth/growth-control mechanisms are involved in naevogenesis and melanomagenesis. Immunoexpression of BRAF/V600E and other molecules (p16, phosphatase and tensin homologue (PTEN), Ki67, hTERT and Cav3.1 and 3.2 calcium channels) were investigated in 80 histopathologically and dermoscopically classified acquired naevi. Regarding BRAF/V600E, dysplastic naevi showed lower immunostaining than common naevi, which was significant in comparison with intradermal naevi, which showed the highest BRAF/V600E histoscore. Junctional naevi showed the lowest BRAF/V600E levels. Globular/cobblestone and reticular dermoscopic patterns were consistently associated with high and low BRAF/V600E immunoexpression, respectively, but Zalaudek’s peripheral globule pattern (CR/PG) showed the highest BRAF/V600E immunoexpression. Among global patterns, the previously not investigated multicomponent pattern showed the lowest BRAF/V600E immunoexpression. Regarding the remaining biomarkers, new immunohistochemical features were found, in particular p16 and PTEN low expression in multicomponent pattern; and Ki67, hTERT and Cav.3.1 high expression in CR/PG. In conclusion, histopathology and dermoscopy provide complementary information regarding the biology of melanocytic naevi.

Estimating malignancy risk of melanocytic choroidal tumours detected in the Australian National Eye Health Survey

ABSTRACT Clinical relevance: The malignant potential of choroidal melanocytic tumours detected incidentally in the community is thought to be low, but this has not been assessed using a validated screening tool. An accurate characterisation of the malignant potential of these lesions has implications for resource allocation, service provision, education, and training. Background: MOLES (Mushroom shape, Orange Pigment, Large size, Enlargement, and Subretinal fluid) categorises tumours as ‘common naevus’, ‘low-risk naevus’, ‘high-risk naevus’, and ‘probable melanoma’. The MOLES system recommends that patients with common naevi (score = 0) undergo review by a community optometrist every two years, ideally with sequential colour photography. For the remaining patients (score ≥ 1), specialist imaging and assessment are recommended, with referral triaged as non-urgent for patients with low-risk (score = 1) or high-risk naevi (score = 2) and urgent for patients with probable melanoma (score > 2). Methods: Lesions flagged as choroidal melanocytic tumours on retinal photographs taken during the Australian National Eye Health Survey were retrospectively analysed by an ocular oncologist. Each lesion was assigned a MOLES score and categorised as common, low-risk, high-risk or probable melanoma. Results: Seventy-seven choroidal naevi were identified. Seventy-five (97%) of the choroidal naevi were categorised as common naevi, with a MOLES score of 0. Two (3%) choroidal naevi had a score of 1 and diagnosed as low-risk naevi due to their size. No naevi had a score of 2 or more. Conclusion: All choroidal naevi detected in this nationally representative population survey were innocuous. This suggests that the vast majority of choroidal melanocytic tumours that are incidentally detected in Australia can be managed in primary eye care settings without the need for specialist referral. MOLES provides a simple evidence-based method for choroidal naevi assessment in primary care.

Atopic dermatitis, naevi count and skin cancer risk: A meta-analysis

BackgroundThe risk of skin malignancy among atopic dermatitis (AD) patients is not well established. ObjectiveWe reviewed the epidemiological evidence on the association between AD, naevi count, and the risk of cutaneous melanoma and keratinocyte skin cancer (KSC). MethodsWe included all studies that compared the naevi count and the risk of skin cancer (melanoma and/or KSC) between AD patients and unaffected individuals. We calculated summary relative risks (SRRs) and 95% confidence intervals (CI) through random effects models; explored correlates of between-studies heterogeneity using sub-group and sensitivity analysis; and assessed publication bias using a funnel-plot-based approach. ResultsThe number of common naevi larger ≥2mm on the whole body was consistently lower among AD patients vs. unaffected individuals when measured by trained health professionals. The risk of melanoma was not increased among AD patients (SRR=0.77, 95%CI 0.44–1.35, I2=85%). We found a significantly increased risk of basal cell cancer (BCC) (SRR=1.34, 95%CI 1.03–1.75, I2=24.0%) but not for squamous cell cancer (SRR=1.91, 95% CI 0.74–4.91, I2=0.0%); however, only a few papers adjusted for phenotypic characteristics and/or sunlight exposure. We found no evidence of publication bias. ConclusionsAD patients may be at increased BCC risk; however, methodological limitations prevented from drawing definitive conclusions. Despite the lack of strong scientific evidence, AD patients should avoid excessive sun exposure, regularly perform skin self examination, and consult a doctor in case of a suspicious skin lesion.

Nævus éruptifs sur épidermolyse bulleuse héréditaire

EB naevus (EBN) are little-known, atypical, eruptive, pigmented melanocytic lesions that may occur in former sites of bullae occurring in epidermolysis bullosa hereditaria (EBH). We sought to describe the characteristics of such lesions and assess their course.This was a retrospective, two-centre study in which data was collated from the medical files of patients with EBN. We analyzed the patients' demographical data as well as the clinical, dermatoscopic, pathological features of EBN and their progression.Eight patients were studied: they were principally Caucasian (5/8), with a sex ratio of 1. All variants of EBH were represented and most were recessive (63%). We analysed 22 EBN, all atypical and emerging before the age of 10 years (73%), ubiquitously distributed and measuring greater than 5 cm(2) (25%). Of the 13 EBN subjected to dermatoscopy, 12 exhibited a benign reticular pattern. Four were biopsied, and analysis revealed three common naevi and one lentigo. After a median follow-up of 8 years, the EBN seen were either stable (68%), had regressed (23%) or had disappeared (one case). No cases of melanoma were diagnosed.EBN are acquired and atypical pigmented naevi. Sixty-four cases of EBN have been reported in the literature up to date. The dermatoscopic features may be evocative of melanoma (17/23 EBN), but to our knowledge no cases of melanoma at a naevus site have been reported. Recessive transmission of EBH appears to be a risk factor (63% of cases), a finding supported by certain pathophysiological hypotheses.EBN present atypical clinical and dermatoscopic features. However, while prophylactic total excision did not appear warranted in the absence of any reported cases of melanoma, regular clinical follow-up is recommended.

Predicting melanoma risk for the Australian population

As melanoma incidence in Australia continues to rise, targeting high-risk individuals for early detection is of paramount importance. We aimed to design a population-specific risk assessment tool to improve on the use of intuition alone for assignment of surveillance strategies for high-risk individuals and help communicate risk more accurately and effectively to patients. Methods used in the development of breast cancer risk models were adopted. Data from a large meta-analysis was used to determine risk estimates. Attributable risk was calculated for each risk factor using data from the Victorian Melanoma Service. Local prevalence data from state cancer registries was incorporated to estimate 5-year risk of melanoma. Independent risk factors identified were common naevi, atypical naevi, hair colour, freckles, family history of melanoma and personal history of non-melanoma skin cancer. Personal history of melanoma was the strongest risk factor for developing another (relative risk 7.28, 7.24). Absolute risk for individuals varies greatly with age, risk factor profiles and proximity to the equator. We have developed a melanoma risk assessment tool based on the best available information (http://www.victorianmelanomaservice.org/calculator). The tool is easily modified as new information becomes available.

Current patterns of the sun protection measures adopted by nurses and the risk factors influencing their compliance

The incidence of skin cancer is increasing worldwide. Included in high risk group are people who have light common phenotypic factors (hair, skin, eyes), have high number of naevi, report previous sunburns and have a family history of skin cancer. Protecting the skin from the sun by wearing protective clothing, using sunscreen and avoiding sun exposure are recommended among primary preventive activities. The purpose of this study was to describe the current patterns of sun protection measures adopted by nurses and to examine the association between compliance with sun protection measures and the main risk factors of melanoma. This cross sectional study was conducted in 2007 during the Annual Greek National Conference of Nursing. Nurses most commonly chose to use sunscreen, to wear glasses, to use an umbrella or to seek for shade in order to protect themselves against sun exposure. Finally, phenotypic factors, previous sunburns and common naevi presence were found to affect nurses’ attitude towards protective measures. This study poses the necessity of targeting high risk groups for melanoma through campaigns aiming to foster sun protection behaviours.

Dysplastic naevi: an update

Dysplastic naevi are clinically atypical and histologically are characterized by architectural disorder and cytological atypia. Their diagnosis is reproducible if criteria and thresholds are agreed upon. They are significant only in relation to melanoma, as simulants of melanoma, as markers of individuals at increased risk of developing melanoma, and as potential and occasional actual precursors of melanoma. Morphologically and biologically, they are intermediate between common naevi and melanoma. Individuals with dysplastic naevi may have deficient DNA repair, and dysplastic naevi lesions are associated with overexpression of pheomelanin, which may lead to increased oxidative damage and increased potential for DNA damage and tumour progression.

In vivo confocal scanning laser microscopy of common naevi with globular, homogeneous and reticular pattern in dermoscopy

A systematic examination and comparison of confocal scanning laser microscopy (CSLM) features of benign naevi showing different dermoscopic patterns has never been performed. Systematically to assess CSLM features of dermoscopically benign reticular, globular and homogeneous naevi and to correlate CSLM findings with dermoscopy and histopathology. CSLM was performed on 30 naevi in 29 patients including 10 reticular, 10 globular and 10 homogeneous naevi showing a uniform pigmentation pattern with dermoscopy. Cytomorphological and architectural features of each naevus were assessed and distinct characteristics for each group of naevi were defined. CSLM features were correlated with the histopathological findings and their applicability for the diagnosis of naevi with different dermoscopic patterns was assessed by two blinded observers. A correct diagnosis was made in 26 and 28 of 30 cases, respectively, by two blinded observers using previously defined CSLM features. Well-defined melanocytic caps, well-defined edged papillae and black papillae concurrently with the absence of white papillae were found in all reticular naevi (10 of 10). Numerous, large junctional/dermal melanocytic nests (10 of 10), ill-defined edged papillae (eight of 10) and white papillae (nine of 10) were found in globular naevi. Homogeneous naevi showed an intermediate pattern between reticular and globular naevi: ill-defined edged papillae (10 of 10), black and white papillae within the same naevus (eight of 10) and junctional/dermal melanocytic nests (three of 10) were seen. Different dermoscopic patterns of benign naevi are reflected in different architectural features in CSLM. As benign naevi show a regular architecture of monomorphous melanocytes in contrast to melanomas, similar dermoscopic features of naevi and early melanomas may be differentiated by CSLM.

Expression of matrilysin (matrix metalloproteinase-7) in primary cutaneous and metastatic melanoma

Matrilysin (MMP-7), a member of the matrix metalloproteinase (MMP) family of proteins, is expressed in various types of malignant tumours. There have been no previous studies of the correlation between matrilysin expression and melanoma. Protein expression of matrilysin was evaluated in human cutaneous melanomas, metastatic melanomas, acquired common melanocytic naevi and Spitz naevi, and the data were corrected with the clinicopathological factors. We retrospectively investigated 18 primary melanomas, 15 metastatic melanomas, 10 common melanocytic naevi and five Spitz naevi samples at our clinic using immunohistochemistry (IHC). Both promatrilysin and active matrilysin were found in the melanoma tissue extracts by Western immunoblotting. In situ hybridization demonstrated that melanoma cells selectively express matrilysin mRNA. Of the melanoma samples, 29 of 33 (87 x 9%) were positive for matrilysin, including 14 of 18 (77 x 8%) primary cutaneous melanomas and 15 of 15 (100%) metastatic melanomas. In contrast, matrilysin was not expressed in common naevi or Spitz naevi. The matrilysin IHC staining score in primary melanomas was associated with the presence of metastases, tumour thickness and TNM staging (P=0 x 001, 0 x 025 and 0 x 021, respectively). The 5-year overall survival was 26.3% for matrilysin-positive cases and 100% for matrilysin-negative cases among melanoma specimen. We found matrilysin expression in primary melanomas and in metastatic melanomas. We further demonstrated that the matrilysin IHC staining score was associated with invasive depth of primary melanoma lesions and metastases. Our observations indicate that matrilysin may be associated with melanoma progression, and may enhance melanoma tumour cell invasion. Therefore, matrilysin may be potentially valuable as a prognostic indicator to predict the clinical behaviour of melanoma.

Fluorescence in situ hybridization (FISH) evaluation of chromosomes 6, 7, 9 and 10 throughout human melanocytic tumorigenesis

Loss of the 9p21 region, 6q and 10q and gain of chromosome 7 are the most frequent chromosomal abnormalities found in human melanomas, but very few cytogenetic data are available regarding dysplastic and common naevi. To study the occurrence of the most consistent chromosomal changes during melanocytic tumorigenesis, archival samples from 30 common naevi and 30 naevus-associated melanomas were analysed by interphase fluorescence in situ hybridization (FISH) using centromeric probes for chromosomes 9 and 7 and locus-specific probes for 9p21, 6q11.1, 6q24.1, 10p15.3 and 10q23.1 regions. In naevus-associated melanomas, separate evaluations were made for sectors corresponding to residual naevus, dysplastic naevus, radial growth phase melanoma and vertical growth phase melanoma. No chromosomal aberrations were found in common naevi, but monosomy 7 was observed in one case. In naevus-associated melanomas, loss of the entire chromosome 9 or of the 9p21 region was observed in 56% of common and 54% of dysplastic naevus sectors, in 64% of radial growth phase melanoma and in 82% of vertical growth phase melanoma. Loss of the long arm of chromosome 6, monosomy 10 and deletion 10q were exclusively confined to radial (18% for both chromosomes) and vertical (29 and 59%, respectively) growth phase melanomas. Polysomy of chromosome 7 was detected only in melanoma sectors (radial growth phase, 14%; vertical growth phase, 59%). The high incidence of 9p21 loss in melanoma-associated naevi, which is maintained in all evolutionary phases of melanocytic tumorigenesis, and the complete absence of chromosomal aberrations in common naevi, strongly suggest that 9p21 loss may be regarded as a cytogenetic marker of melanocytic naevi with a high potential for progression.

VEGF and VEGFR-2 immunohistochemistry in human melanocytic naevi and cutaneous melanomas

Vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR-2) play a key role in vasculogenesis and angiogenic sprouting, which are crucial for tumour development and metastasis. In order to determine their possible role in the acquisition of metastatic potential throughout melanocytic tumour progression, VEGF and VEGFR-2 immunohistochemical expression were evaluated in 36 human melanocytic tumours of the skin (24 malignant melanomas and 12 common naevi). Different VEGFR-2 immunostaining patterns were detected in the vast majority of melanomas (21/24; 88%). A nuclear membrane-like pattern was mainly associated with in situ and microinvasive melanomas, whereas a combined cytoplasmic membrane and nuclear membrane-like pattern was seen in invasive melanomas. A nuclear membrane-like pattern was also observed in 83% (10/12) of common naevi. Cytoplasmic immunostaining for VEGF was observed in 72% (8/11) of in situ/microinvasive melanomas, 84% (11/13) of invasive melanomas and 91% (11/12) of naevi. CD31 was also investigated as an immunohistochemical marker for microvessel density (MVD) evaluation. No associations were found between MVD and VEGF/VEGFR-2 expression. Taken together, these data indicate that VEGF production is a common event in benign melanocytic tumours, whereas VEGFR-2 expression, co-localized in the cytoplasmic and nuclear membrane, is associated with progression towards invasive melanoma. The role exerted by VEGF/VEGFR-2, however, seems to be independent of the development of a tumour-related capillary network.

Skin abnormalities in the National Portrait Gallery.

Pathological changes in the human body have long been recognised in painting. To assess the frequency of potential physical abnormalities reflected in paintings, we reviewed portraits on display at one visit in the National Portrait Gallery in London. We identified a number of possible abnormalities, most of them dermatological, with the commonest finding being small facial papular lesions, most likely representing either common warts or dermal naevi. This exercise however, reflects a subjective interpretation of the different artists's perceptions of their models' physical appearances.

Spitz naevi may express components of the plasminogen activation system.

The plasminogen activation (PA) system is involved in the process of invasion and metastasis. Its major components are urokinase (uPA) and tissue-type plasminogen activator (tPA), plasminogen activation inhibitor type 1 and 2 (PAI-1 and PAI-2) and a receptor for urokinase (uPAR). In this study, the expression of plasminogen activation components in Spitz naevi was compared with that in common and dysplastic naevi on the one hand and primary cutaneous melanomas on the other. Spitz naevi had melanocytic positivity for uPA in 0% (0/36), tPA in 30% (6/20), PAI-1 in 10% (3/35), PAI-2 in 40% (8/21) and uPAR in 60% (13/21) of cases. This far exceeded the expression found in common (n = 25) and dysplastic (n = 15) naevi, which only showed melanocytic positivity for PAI-2 (20% and 15% respectively) and in one dysplastic naevus also for uPAR. This was much (for most components significantly) less than the proportion of primary melanomas with tumour cell positivity, which was 30% (11/38) for uPA, 80% (19/24) for tPA, 75% (28/38) for PAI-1, 80% (19/24) for PAI-2 and 80% (19/24) for uPAR. The main findings of this study are that Spitz naevi, firstly, may express plasminogen activator (tPA), inhibitors and the receptor of the PA system, but in a much smaller proportion than cutaneous melanomas; and secondly, do not express urokinase, whereas some of the melanomas do. uPA positivity may therefore be suggestive of melanoma. However, overlapping staining results imply that the PA system has limited value in the differential diagnosis between Spitz naevus and primary melanoma. As serine protease components are expressed, Spitz naevi may use this proteolytic machinery to accomplish matrix degradation, although in a more restricted, possibly transient manner than melanomas.

Quantitative in situ evaluation of telomeres in fluorescence in situ hybridization-processed sections of cutaneous melanocytic lesions and correlation with telomerase activity.

Telomere length is correlated with cellular ageing and immortalization processes. In some human cancers telomere length measurement has proved to be of diagnostic and prognostic value. Results comparable with the traditional terminal restriction fragment length determination by Southern blotting have been obtained in metaphase and interphase cells in some studies by fluorescence in situ hybridization (FISH) analysis; FISH additionally allows for the quantification of telomeres at the cellular level. In this study, 32 melanocytic lesions were analysed by FISH, aiming at investigating possible telomere differences among various benign and malignant lesions and correlation with telomerase activity (TA) level. FISH was performed on paraffin sections from six common naevi, eight Spitz naevi, 12 melanomas, six melanoma metastases and nine control samples of normal skin. Telomere mean maximum diameter (Feret max), area and number per nuclear area were calculated by image analysis on fluorescent images elaborated through KS400 and in situ imaging system (ISIS) for FISH analysis programs. Mean TA level was also calculated in all lesions and correlated with telomere parameters. Telomere number per nuclear area was significantly lower in melanomas and metastases than in benign common and Spitz naevi and in control skin (7 small middle dot24 +/- 3.3; 6.11 +/- 3 vs. 14.46 +/- 5.6; 16.92 +/- 7.8; and 12.59 +/- 3.4, respectively; P < 0 .001). No significant differences were found for the other telomere parameters. In common and Spitz naevi, telomere number was positively correlated with Feret max (P = 0.046 and P < 0.0001, respectively). TA was significantly higher in melanomas and metastases than in the other groups (70.18 +/- 25.2; 105.07 +/- 30 vs. 2.16 +/- 2.4; 2 .99 +/- 2.1; 2 +/- 1.2, respectively; P< or = 0. 001) and it was inversely correlated with telomere number per nuclear area in melanomas (P = 0.0041). No other significant correlations were found. Encouraging results have been obtained from quantitative telomere evaluation in the diagnosis of melanocytic lesions, although an analysis of a larger number of cases would be necessary to provide more reliable data. An extreme shortening of some telomeres probably results in the decrease of telomeric signals and the lower mean number of detectable telomeres in melanomas and metastases. In melanomas, telomere number per nuclear area is also inversely correlated with TA levels. Quantitative FISH of melanocytic lesions could give more specific information at the cellular level in telomere and telomerase fields of investigation.

Seasonal pattern of the excision rate of melanoma and naevi.

Based on available information that melanocytic skin lesions presenting a junctional component are more susceptible to the influence of ultraviolet radiation, this study compares the seasonal differences between the excision rates of melanocytic skin lesions with a junctional component to those without. The histological diagnoses of 1230 patients with melanocytic skin lesions were retrospectively analysed. Depending on the histological diagnosis four groups were formed: melanomas, dysplastic naevi, common naevi (junctional and compound naevi), and dermal naevi. All dates of operations were allocated to summer or winter halves of the year. The collected data were computer analysed for statistical description. The number of excisions of melanocytic lesions with a junctional component (melanoma, dysplastic naevi, common naevi) showed an impressive seasonal variation, with a peak during the summer months, while the excision frequency of dermal naevi was approximately constant during the year. In conclusion, we suggest that ultraviolet radiation may contribute to the seasonal pattern of excision of melanoma and naevi only when a junctional component is present.

Expression of neurotrophins and their receptors in pigment cell lesions of the skin.

The neurotrophins (NTs) are a group of growth factors involved in the development of the nervous system and presumed to play a role in neural crest-derived tumours. The expression of three NTs (NGF, BDNF, and NT-3) and their receptors (NTRs; i.e. low-affinity pan-NT receptor p75, Trk-B, and Trk-C) was studied in frozen sections of benign and malignant cutaneous pigment cell lesions, using immunohistochemistry. In order to understand the possible role of these growth factors and their receptors in the progression of primary cutaneous malignant melanomas (PCMMs), their distribution in the radial (RGP) and vertical (VGP) growth phases was particularly studied. While most of the common acquired naevi were unreactive, Spitz and blue naevi showed scattered immunoreactive cells, especially for the p75 NTR. Dysplastic naevi, but not common naevi, expressed NT-3 in their junctional component. PCMM and melanoma metastases often showed a diffuse pattern of immunostaining. NT-3 was significantly more frequently expressed in the RGP of PCMMs than in the junctional component of benign naevi, whereas more extensive immunoreactivity for NGF was found in the VGP of PCMMs, compared with the RGP; metastases more frequently expressed NGF, BDNF, and Trk-B than PCMMs. Interestingly, neurotropic melanoma expressed all NTs/NTRs except Trk-B. These immuunohistochemical data confirm suggestions from previous in vitro studies that autocrine loops of certain NTs and their respective receptors may be involved in melanoma progression; in addition, NT-3 may be involved in the junctional growth of dysplastic naevi. The precise role of these growth factors in melanoma, however, will await further functional studies.

Computer-aided epiluminescence microscopy of pigmented skin lesions: the value of clinical data for the classification process.

Early melanoma is often difficult to differentiate from benign pigmented skin lesions (PSLs). Digital epiluminescence microscopy (DELM) and automated image analysis could represent possible aids for inexperienced clinicians. We designed an automated computerized image analysis system that has the potential for use as an additional tool for the differentiation of melanoma from dysplastic naevi and common naevi. The PC-based pilot system was attached to a common DELM system as the image source. Digital images of PSLs were automatically segmented and a panel of 107 morphological parameters were measured. Additionally, seven clinical parameters were evaluated and used as an additional source of information. Neural networks were then trained to distinguish melanoma from benign PSLs. One class of networks was trained solely based on the morphometric features, whereas the second class of networks was trained on the combination of morphometric and clinical features. The automatic segmentation algorithm was correct in 96% of cases. Using three-way receiver operating characteristic (ROC) analysis, for networks trained solely on morphometric features the volume under surface (VUS) was 0.617 (SD 0.036). The performance was significantly better for networks trained on the combination of both morphometric and clinical features (VUS = 0.682, SD 0.035). In a dichotomous model, distinguishing benign lesion (common naevi + dysplastic naevi) from melanoma, the area under the curve (AUC) from two-way ROC analysis was 0.942 (SD 0.018) for networks trained solely on morphometric features and 0.968 (SD 0.012) for those trained on the combination of clinical and morphometric data (P= NS). Automated feature extraction from PSLs and the training of neural networks as classifiers has thus shown satisfactory performance in a large scale experiment. The addition of clinical data significantly increases the diagnostic performance for distinguishing three classes of lesions (i.e. common naevi, dysplastic naevi and melanoma). Such integrated systems hold promise as a decision aid for the diagnosis of PSLs.

Prevalence of pigmented naevi in a Swedish population living close to the Arctic Circle.

The prevalence of common naevi and dysplastic naevi was investigated in a Swedish population with a low incidence of melanoma. A total of 201 subjects aged 30-50 years living in northern Sweden participated. The median number of common naevi per individual was 15, and 11% had dysplastic naevi. Higher numbers of common naevi were found in individuals with dysplastic naevi (median 68) and in those who had spent their childhood in southern Sweden (median 44). The prevalence of common naevi and dysplastic naevi was significantly lower than reported from a previously studied population in southern Sweden, with a melanoma incidence 4 times higher than in the north. The strong variability in naevus phenotype, and in melanoma incidence, between different regions of Sweden seems to be due to different levels of sun exposure rather than to differences in constitutional factors.

Epiluminescence microscopy features of cutaneous malignant melanoma metastases

Especially small and/or initial cutaneous malignant melanoma metastases (CMMMs) are tumours with inconspicuous clinical and sometimes histological features which may be difficult to differentiate from benign melanocytic lesions or angiomas. Thus it would be very valuable to have additional criteria for the differential diagnosis of such lesions. Thirty histologically verified CMMMs were examined using epiluminescence microscopy (ELM) in order to visualize a large number of morphological features permitting the recognition of malignancy. One hundred primary cutaneous malignant melanomas (PCMMs), 50 dysplastic naevi, 50 common naevi, 30 blue naevi and 20 haemangiomas served as the control group; these were randomly selected from a large data base and were all reviewed for histological diagnosis. Four of the 24 features studied were shown to differ significantly between CMMMs and the control group. Two features of the malignant tumour group (CMMM and PCMM) differed significantly from the benign tumour group. A polymorphic angiectatic base pattern and/or vascular aneurysms, peripheral erythema, brown-grey coloration as a negative criterion (i.e. its absence is indicative of CMMM) and a light brown halo had a specificity of 86.7-96.0% for CMMM. Areas of polymorphic and/or horizontally dilated capillaries and a saccular pattern had a specificity of 97.3-99.2% for the malignant group (CMMM and PCMM). Three features - peripheral greyish patches, lesions surrounded by grey streaks (melanoma cell infarcts of the vessels) and microscopic ovoid blood lakes (spontaneous microhaemorrhages)--were absent in the benign group. The prevalence of distinct ELM criteria in CMMM represents a useful enhancement for the diagnosis of malignancy in melanocytic skin lesions.

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.