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PubMed2000

Dermatoscopy in the diagnosis of pigmented skin lesions: a new semiology for the dermatologist.

Dermatoscopy or epiluminescence microscopy (ELM), is a noninvasive method that enables clinicians to evaluate fully--by means of a magnified oil immersion diascopy--numerous morphological features, not visible with the naked eye, which enhance the diagnosis of nearly all pigmented skin lesions. In recent years, a burst of research activity in this topic has been carried out, dealing with different aspects, and new frontiers, of this technique. First, a continuous refinement of dermatoscopic terminology is undertaken, paying particular attention to the diagnostic performance of dermatoscopy at peculiar anatomical sites and to the building of different dermatoscopic algorithms aimed at a simplified diagnosis of melanoma, even for less experienced observers. Another point of interest concerns the possible role of dermatoscopy in the pre-operative assessment of melanoma thickness. Finally, promising data about the role of digital equipment in the follow up of melanocytic skin lesions as well as in the automated diagnosis of pigmented skin lesions have been recently reported. This paper should enable readers to become familiar with the procedure and terminology of ELM in the diagnosis of pigmented skin lesions encouraging a greater understanding of different methods (pattern analysis, algorithms) in the diagnosis of melanoma using ELM.

Algorithms↗
PubMed2005

Automated segmentation of pigmented skin lesions in multispectral imaging.

The aim of this study was to develop an algorithm for the automatic segmentation of multispectral images of pigmented skin lesions. The study involved 1700 patients with 1856 cutaneous pigmented lesions, which were analysed in vivo by a novel spectrophotometric system, before excision. The system is able to acquire a set of 15 different multispectral images at equally spaced wavelengths between 483 and 951 nm. An original segmentation algorithm was developed and applied to the whole set of lesions and was able to automatically contour them all. The obtained lesion boundaries were shown to two expert clinicians, who, independently, rejected 54 of them. The 97.1% contour accuracy indicates that the developed algorithm could be a helpful and effective instrument for the automatic segmentation of skin pigmented lesions.

Adolescent↗
PubMed2002

Spectrophotometric intracutaneous analysis: a new technique for imaging pigmented skin lesions.

BACKGROUND: Spectrophotometric intracutaneous analysis (SIA) is a new technique for imaging pigmented skin lesions and for diagnosing melanoma. The SIAscope produces eight narrow-band spectrally filtered images of the skin over an area of 24 x 24 mm with radiation ranging from 400 to 1000 nm. OBJECTIVES: To present the early results of a clinical trial with SIA. METHODS: Spectrophotometric inputs from the skin were analysed using complex algorithms to return high-resolution information regarding total melanin content of the epidermis and papillary dermis, collagen and haemoglobin content as well as the presence of melanin in the papillary dermis. RESULTS: Simple, highly reproducible and reliable features were identified, e.g. the presence of dermal melanin, collagen holes and 'erythematous blush' with blood displacement. These simple features were found to be highly specific (80.1%) and sensitive (82.7%) for melanoma in a dataset of 348 pigmented lesions (52 melanomas) and compared very favourably with dermatoscopy when analysed using receiver-operator characteristic curves. CONCLUSIONS: This first clinical trial with SIAscopy has yielded very promising results and delivers new, useful information to the clinician diagnosing pigmented skin lesions.

Collagen↗
PubMed2002

Digital dermoscopy analysis of atypical pigmented skin lesions: a stepwise logistic discriminant analysis approach.

BACKGROUND: Digital microscopy is a non-invasive diagnostic technique enabling determination of characteristics that cannot be appreciated by direct observation. If correctly applied, this technique can be useful for the diagnosis of pigmented skin lesions. PURPOSE: To evaluate the utility of digital microscopy for analysing atypical benign and malignant pigmented skin lesions exploiting digital numerical filtering and automatic measurements. METHODS: Forty-eight parameters were identified as possible discriminating variables, and were grouped in four categories: geometries, colours, textures, and islands of colour. Statistical analysis was used to identify the variables with the highest discriminating power. RESULTS: The high quality of the digital image made it possible to observe diagnostic signs in pigmented skin lesion images, acquired by the present technique, in great detail. Specially designed filtering enhanced certain diagnostic patterns. Stepwise discriminant analysis selected only 10 variables (the means of these variables were higher in melanomas than in nevi). CONCLUSIONS: The combined use of digital dermoscopy and stepwise logistic discriminant analysis made it possible to single out the best objective variables for distinguishing atypical nevi and early melanoma.

Diagnosis, Computer-Assisted↗
PubMed1992

Pulmonary infiltrates and skin pigmentation associated with sulfasalazine.

A patient with ulcerative colitis developed skin pigmentation and diffuse pulmonary shadowing without respiratory symptomatology, while taking sulfasalazine. The clinical picture and radiological abnormalities disappeared spontaneously on discontinuation of the drug. Histopathological studies from specimens taken by transbronchial biopsy showed bronchiolitis obliterans with fibrosing alveolitis. Sulfasalazine-induced lung disorder is an extremely rare entity which must be considered in all ulcerative colitis patients while on sulfasalazine therapy, despite the absence of pulmonary symptomatology.

Aged↗
PubMed2003

Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet.

BACKGROUND: There is a need for better standardization of the dermoscopic terminology in assessing pigmented skin lesions. OBJECTIVE: The virtual Consensus Net Meeting on Dermoscopy was organized to investigate reproducibility and validity of the various features and diagnostic algorithms. METHODS: Dermoscopic images of 108 lesions were evaluated via the Internet by 40 experienced dermoscopists using a 2-step diagnostic procedure. The first-step algorithm distinguished melanocytic versus nonmelanocytic lesions. The second step in the diagnostic procedure used 4 algorithms (pattern analysis, ABCD rule, Menzies method, and 7-point checklist) to distinguish melanoma versus benign melanocytic lesions. kappa Values, log odds ratios, sensitivity, specificity, and positive likelihood ratios were estimated for all diagnostic algorithms and dermoscopic features. RESULTS: Interobserver agreement was fair to good for all diagnostic methods, but it was poor for the majority of dermoscopic criteria. Intraobserver agreement was good to excellent for all algorithms and features considered. Pattern analysis allowed the best diagnostic performance (positive likelihood ratio: 5.1), whereas alternative algorithms revealed comparable sensitivity but less specificity. Interobserver agreement on management decisions made by dermoscopy was fairly good (mean kappa value: 0.53). CONCLUSION: The virtual Consensus Net Meeting on Dermoscopy represents a valid tool for better standardization of the dermoscopic terminology and, moreover, opens up a new territory for diagnosing and managing pigmented skin lesions.

Algorithms↗
PubMed2001

A comparison of machine learning methods for the diagnosis of pigmented skin lesions.

We analyze the discriminatory power of k-nearest neighbors, logistic regression, artificial neural networks (ANNs), decision tress, and support vector machines (SVMs) on the task of classifying pigmented skin lesions as common nevi, dysplastic nevi, or melanoma. Three different classification tasks were used as benchmarks: the dichotomous problem of distinguishing common nevi from dysplastic nevi and melanoma, the dichotomous problem of distinguishing melanoma from common and dysplastic nevi, and the trichotomous problem of correctly distinguishing all three classes. Using ROC analysis to measure the discriminatory power of the methods shows that excellent results for specific classification problems in the domain of pigmented skin lesions can be achieved with machine-learning methods. On both dichotomous and trichotomous tasks, logistic regression, ANNs, and SVMs performed on about the same level, with k-nearest neighbors and decision trees performing worse.

Algorithms↗
PubMed2000

Fusiform incisional biopsy for pigmented skin lesions.

Current recommendations for biopsy of a pigmented skin lesion suspected of being melanoma include complete excision when possible. Because benign pigmented lesions do not warrant excisional biopsy, especially when they are large and/or on cosmetically sensitive sites, incisional biopsy is desirable. For such lesions we recommend a fusiform incisional biopsy. This tissue sampling technique not only yields an excellent cosmetic outcome, but also provides the pathologist with an optimal biopsy specimen in which he/she can assess the symmetry, circumscription, breadth, and depth of the lesion.

Biopsy↗
PubMed1996

Photography and densitometry to measure skin pigmentation caused by ultraviolet exposure.

This was a project that a final year physiotherapy student was undertaking. Part of the project required the measurement of skin pigmentation before and after treatment with a standard E2 UV dose. The measurement of skin redness was undertaken using an erythema meter, and it was necessary to use photographic and densitometric techniques to measure skin pigmentation. The results of this experiment proved to be consistent with other published papers on the way that skin types react on exposure to standard UV doses. This paper describes the photographic method and procedures that were used and the way the raw data was treated so that it could be used for statistical analysis by the physiotherapy student.

Densitometry↗
PubMed2003

Skin pigmentation, biogeographical ancestry and admixture mapping.

Ancestry informative markers (AIMs) are genetic loci showing alleles with large frequency differences between populations. AIMs can be used to estimate biogeographical ancestry at the level of the population, subgroup (e.g. cases and controls) and individual. Ancestry estimates at both the subgroup and individual level can be directly instructive regarding the genetics of the phenotypes that differ qualitatively or in frequency between populations. These estimates can provide a compelling foundation for the use of admixture mapping (AM) methods to identify the genes underlying these traits. We present details of a panel of 34 AIMs and demonstrate how such studies can proceed, by using skin pigmentation as a model phenotype. We have genotyped these markers in two population samples with primarily African ancestry, viz. African Americans from Washington D.C. and an African Caribbean sample from Britain, and in a sample of European Americans from Pennsylvania. In the two African population samples, we observed significant correlations between estimates of individual ancestry and skin pigmentation as measured by reflectometry (R(2)=0.21, P<0.0001 for the African-American sample and R(2)=0.16, P<0.0001 for the British African-Caribbean sample). These correlations confirm the validity of the ancestry estimates and also indicate the high level of population structure related to admixture, a level that characterizes these populations and that is detectable by using other tests to identify genetic structure. We have also applied two methods of admixture mapping to test for the effects of three candidate genes (TYR, OCA2, MC1R) on pigmentation. We show that TYR and OCA2 have measurable effects on skin pigmentation differences between the west African and west European parental populations. This work indicates that it is possible to estimate the individual ancestry of a person based on DNA analysis with a reasonable number of well-defined genetic markers. The implications and applications of ancestry estimates in biomedical research are discussed.

Africa↗
PubMed2004

Deoxypodophyllotoxin reduces skin pigmentation of brown Guinea pigs.

In this report, we have demonstrated that deoxypodophyllotoxin from Anthriscus sylvestris (L.) Hoffm decreases UV-induced skin pigmentation of brown guinea pigs. Deoxypodophyllotoxin (0.05 % in propylene glycol: ethanol: water = 5 : 3:2) was topically applied twice daily for two weeks to dorsal skin of brown guinea pigs that were exposed to UV irradiation using a solar simulator. Visual inspection and Fontana-Masson staining both demonstrated that deoxypodophyllotoxin reduced skin pigmentation and total epidermal melanin when compared to that of vehicle-treated areas, suggesting that deoxypodophyllotoxin maybe applicable to treat hyperpigmentation.

Administration, Cutaneous↗
PubMed2001

Dose response for UV-induced immune suppression in people of color: differences based on erythemal reactivity rather than skin pigmentation.

Ultraviolet radiation (UVR) is known to suppress immune responses in human subjects. The purpose of this study was to develop dose responses across a broad range of skin pigmentation in order to facilitate risk assessment. UVR was administered using FS 20 bulbs. Skin pigmentation and UVR sensitivity were evaluated using Fitzpatrick classifications, minimal erythemal dose (MED), slope of the erythemal dose response curve (sED), baseline pigmentation and tanning response. To assess immune responses dinitrochlorobenzene (DNCB) was applied to irradiated buttock skin 72 h after irradiation. Two weeks later DNCB was applied to the inside upper arm. Skin thickness was measured before and after challenge. Dose response was modeled (to obtain a regression line) for the entire group of 185 subjects. With the exception of sED none of the above-mentioned pigmentation indicators contributed significantly to variability around the regression line. Thus, differences in sensitivity for multiple skin types based on Fitzpatrick classification or MED were not observed. However, differences in immune sensitivity to UVR were detected between subjects with steep erythemal dose response curves and those with moderate or flat responses. For subjects with steep erythemal responses the dose calculated to suppress the immune response by 50% was 114 mJ/cm2. This group included individuals with Fitzpatrick skin types I-V, MED for these subjects ranged from 30 to 80 mJ/cm2. The 50% suppression dose for subjects with weak or no erythemal response could not be computed (the dose response was flat). This resistant group included subjects with skin types IV-VI and MED for these subjects ranged from 41 to > 105 mJ/cm2. This study provides a human dose response for UVR suppression of contact sensitivity that will be useful in risk assessment. It is the first study to provide this information using the FS sun lamp and is the first study to include people of color. The sED appears to be a new variable for identifying sensitive subjects at risk of UVR-induced immune suppression.

Adolescent↗
PubMed2001

Skin pigmentation enhancers.

The highest incidences of cancer are found in the skin, but endogenous pigmentation is associated with markedly reduced risk. Agents that enhance skin pigmentation have the potential to reduce both photodamage and skin cancer incidence. The purpose of this review is to evaluate agents that have the potential to increase skin pigmentation. These include topically applied substances that simulate natural pigmentation: dihydroxyacetone and melanins; and substances that stimulate the natural pigmentation process: psoralens with UVA (PUVA), dimethylsulfoxide (DMSO), L-tyrosine, L-Dopa, lysosomotropic agents, diacylglycerols, thymidine dinucleotides, DNA fragments, melanocyte stimulating hormone (MSH) analogs, 3-isobutyl-1-methylxanthine (IBMX), nitric oxide donors, and bicyclic monoterpene (BMT) diols. These agents are compared with regards to efficacy when administered to melanoma cells, normal human epidermal melanocytes, animal skin, and human skin. In addition, mechanisms of action are reviewed since these may reveal issues related to both efficacy and safety. Both dihydroxyacetone and topically applied melanins are presently available to the consumer, and both of these have been shown to provide some photoprotection. Of the pigmentation stimulators, only PUVA and MSH analogs have been tested extensively on humans, but there are concerns about the safety and side effects of both. At least some of the remaining pigmentation stimulators under development have the potential to safely induce a photoprotective tan.

Animals↗
PubMed2003

A new algorithm for border description of polarized light surface microscopic images of pigmented skin lesions.

The aim of this study was to provide mathematical descriptors for the border of pigmented skin lesion images and to assess their efficacy for distinction among different lesion groups. New descriptors such as lesion slope and lesion slope regularity are introduced and mathematically defined. A new algorithm based on the Catmull-Rom spline method and the computation of the gray-level gradient of points extracted by interpolation of normal direction on spline points was employed. The efficacy of these new descriptors was tested on a data set of 510 pigmented skin lesions, composed by 85 melanomas and 425 nevi, by employing statistical methods for discrimination between the two populations.

Algorithms↗
PubMed1967

Skin-pigment regulation of vitamin-D biosynthesis in man.

The known correlation between the color of human skin and latitude (Fig. 2) is explainable in terms of two opposing positive adaptations to solar ultraviolet radiation, weak in northern latitudes in winter yet powerful the year around near the equator. In northern latitudes there is selection for white skins that allow maximum photoactivation of 7-dehydrocholesterol into vitamin D at low intensities of ultraviolet radiation. In southern latitudes, on the other hand, there is selection for black skins able to prevent up to 95 percent of the incident ultraviolet from reaching the deeper layers of the skin where vitamin D is synthesized. Selection against the twin dangers of rickets on the one hand and toxic doses of vitamin D on the other would thus explain the world-wide correlation observed between skin pigmentation and nearness to the equator.

Adaptation, Physiological↗
PubMed2001

Long-pulsed Nd:YAG laser-assisted hair removal in pigmented skin: a clinical and histological evaluation.

OBJECTIVE: To determine the safety and effectiveness of a long-pulsed Nd:YAG laser at 1064 nm in effecting long-term hair reduction in patients with darkly pigmented skin. DESIGN: Nonrandomized before-after clinical and histological trial. SETTING: Private practice, ambulatory care facility. PATIENTS: Twenty women with skin phototypes IV through VI and dark brown to black terminal hair on the face, axillae, or legs. INTERVENTION: A series of 3 long-pulsed (50-millisecond) 1064-nm Nd:YAG laser treatments at fluences ranging from 40 to 50 J/cm(2) were delivered to the identified treatment areas on a monthly basis by a single operator. MAIN OUTCOME MEASURES: Global clinical grading scores of comparable before-after treatment photographs were determined by 2 independent medical assessors during each laser session and 1, 3, 6, and 12 months postoperatively. A dermatopathologist reviewed unmarked histological specimens obtained at baseline, immediately after the initial laser treatment, and at 1 and 6 months after the final laser session. RESULTS: Substantial hair reduction was seen after each of the 3 treatment sessions. Prolonged hair loss was observed 12 months after the final laser treatment (70%-90% hair reduction). Axillary hair was substantially more responsive to laser irradiation than was hair located on the legs and face. Adverse effects included mild to moderate treatment pain and rare occurrences of vesiculation and transient pigmentary alteration without fibrosis or scarring. Histological tissue changes mirrored clinical response rates, with evidence of selective follicular injury without epidermal disruption. CONCLUSION: The long-pulsed 1064-nm Nd:YAG laser is a safe and effective method of long-term hair reduction in patients with darkly pigmented skin.

Adult↗
PubMed1995

Laser resurfacing in pigmented skin.

BACKGROUND: Laser skin resurfacing is a very promising new treatment for solar elastosis and acne scars. The Ultrapulse carbon dioxide (CO2) laser and the SilkTouch flashscanner allow precise depth control and char-free ablation. Earlier studies have been done mainly on Caucasian skin types I and II, but very little data were available on pigmented skin. OBJECTIVE: The purpose of this study is to assess the efficacy and safety of laser skin resurfacing in skin types III and IV. METHODS: Thirty Asian and Hispanic patients were treated for facial rhytides and acne scars. All patients were instructed to use tretinoin cream 0.05%, hydroquinone 5%, and desonide 0.1% cream nightly for 2-4 weeks prior to the laser treatment. The Ultrapulse 5000C CO2 laser with the Truespot 3-mm collimated handpiece at the setting of 250-450 mJ per pulse, or the Silk-Touch flashscanner at the setting of 5-7 W, 0.2-second pulse duration, and 4-mm (M) spot size, was used. Patients were evaluated clinically, and global response was assessed by both clinicians and patients. RESULTS: The facial rhytides and acne scars improved 25-50% in all patients after one laser treatment. The most common side effects were persistent erythema that resolved on the average of 6 weeks. Hyperpigmentation occurred, but was reduced with regular use of tretinoin, hydroquinone, and desonide cream both pre- and postoperatively along with use of broad spectrum sunscreen after treatments. CONCLUSION: Laser skin resurfacing can be used to treat facial rhytides and acne scars in skin phototypes III and IV. When proper pre- and postoperative management is implemented, the risk of dyspigmentation can be reduced.

Acne Vulgaris↗