Diagnostic utility of magnetic resonance imaging in malignant melanoma.

BACKGROUND: Dermatologists sometimes have difficulty in making the diagnosis of a melanocytic tumor. OBJECTIVE: Our purpose was to establish a noninvasive method for the diagnosis of malignant melanoma. We investigated the diagnostic usefulness of magnetic resonance imaging (MRI) in 23 lesions of primary malignant melanoma, metastatic malignant melanoma, and benign pigmented skin tumors. METHODS: The morphologic characteristics and the signal intensity of the tumors were analyzed to differentiate malignant and benign pigmented skin tumors by means of the tumor-to-fat contrast ratio of the signal intensity. RESULTS: The morphologic characteristics of the tumors obtained by MRI were not an absolute criterion for diagnosis of malignant melanoma, but the signal intensity of the tumor assessed by the tumor-to-fat contrast ratio on T2-weighted images clearly differentiated between primary malignant melanoma and benign pigmented skin tumors. CONCLUSION: These findings indicated that MRI is useful for noninvasive diagnosis of malignant melanoma.     

Laypersons' perceptual discrimination of pigmented skin lesions

BACKGROUND: Most cutaneous malignant melanomas of the skin are visible and should, at least in theory, be possible to detect with the naked eye. OBJECTIVE: This study was conducted to learn more about laypersons' ability to discriminate between benign pigmented lesions and malignant ones. METHODS: Four groups of laypersons (n = 120) were asked to evaluate pictures of different types of pigmented skin lesions, before and after they received information about the ABCD (asymmetry, border irregularity, color variegation, and diameter greater than 6 mm) criteria, with respect to the necessity of action. RESULTS: The respondents made adequate assessments of melanomas but overestimated the danger of benign pigmented skin lesions. Information about the ABCD criteria enhanced their ability to make adequate assessments. CONCLUSION: People seem to make adequate decisions concerning how to act if they have a melanoma. On the other hand, common moles and dysplastic nevi were harder to discriminate. Providing information to the public about the features of melanomas, in accordance with the ABCD criteria, might help laypersons in their perceptual discrimination of skin lesions.     

Optical transfer diagnosis of pigmented lesions: a pilot study

Objective: To evaluate the potential of a novel imaging technology, optical transfer diagnosis (OTD), for differentiation of benign from malignant pigmented melanocytic lesions.
Design: Patients with pigmented lesions suspicious for melanoma were referred for OTD. After scanning, lesions were biopsied for histopathologic examination, each by two separate dermatopathologists. To create morphologic–physiologic maps, the imaging system used the morphologic and physiologic parameters derived from prediction models of light absorption and scattering by chromophores such as hemoglobin, keratin, and melanin at different epidermal and dermal depths. The relative entropies were analyzed for output prediction of malignancy vs. nonmalignancy.
Setting: General dermatology clinic in a tertiary care academic medical center.
Patients: Fifty patients with suspected melanoma.
Intervention: OTD of pigmented lesions suspicious for melanoma, followed by biopsies for histopathologic examination.
Main outcome measures: Histopathologic confirmation of malignant lesions identified by OTD as melanoma.
Results: Sixty-three pigmented suspicious lesions were scanned before being biopsied for histopathologic examination by the two dermatopathologists. Of the 63 lesions, five were identified as melanoma and 58 were found to be benign (including three seborrheic keratoses and 55 melanocytic nevi). OTD was able to identify the malignant lesions with 100% sensitivity and 94.8–96.6% specificity.
Conclusions: Further study is indicated, but this technology is a promising adjunct to clinical skin cancer screening. Additionally, if the physiologic prediction models can be validated, OTD may facilitate the noninvasive study of some aspects of cutaneous physiology.     

Assessment of pigmented skin lesions in terms of blood perfusion estimates

Background/aims: Cutaneous malignant melanoma is a disease of increasing clinical and economical importance. The prognosis is good with early diagnosis. The chief differential diagnosis is benign melanocytic naevus, a common lesion in Caucasians. Attempts have been made to use bioengineering techniques to aid in the initial diagnosis. The present study proposes a method of extracting possibly discriminative blood perfusion properties in pigmented skin lesions by combining information on the lesions' blood perfusion with optical or visual information of their spatial extent. Methods: A total of 46 blood perfusion measurements were performed on 22 pigmented skin lesions, the ultimate diagnosis of which was three histologically proven malignant melanomas, four histologically proven benign naevi and fifteen naevi assessed by two specialist dermatologists as being benign. Laser Doppler perfusion imaging gave two different types of two‐dimensional data sets (64×64 pixels), one representing the total backscattered light intensity at each measurement point (TLI image) and the second corresponding to perfusion values. The boundaries of each examined lesion were derived from the TLI image employing greyscale thresholding, thus resulting in an estimated region of interest (ROI) approximating the optical extent of the lesion. The ROI was superimposed on the perfusion image and extraction of perfusion features was then performed. Results: The processing of the TLI images was successful in delineating the lesions' boundaries. The first hypothesis that the mean perfusion quotients in MM and benign naevi are equal could not be rejected at the chosen 5% level of significance. The second hypothesis that the mean percent‐age of elevated perfusion values (image pixels) within the ROI shows no difference between MM and benign naevi could be rejected at a 5% level of significance. Conclusions: This study has presented a method of extracting blood perfusion parameters of pigmented skin lesions by combining blood perfusion information with information on the lesion's optical extent. The proposed method of presenting data could prove to be a useful discriminative adjunct in the assessment of pigmented skin lesions.     

A relative color approach to color discrimination for malignant melanoma detection in dermoscopy images

BACKGROUND: Skin lesion color is an important feature for diagnosing malignant melanoma. In previous research, skin lesion color was investigated for discriminating malignant melanoma lesions from benign lesions in clinical images. Colors characteristics of melanoma were determined using color histogram analysis over a training set of images. Percent melanoma color and color clustering ratio features were used to quantify the presence of melanoma-colored pixels within skin lesions for skin lesion discrimination. METHODS: In this research, the relative color histogram analysis technique is used to evaluate skin lesion discrimination based on color feature calculations in different regions of the skin lesion in dermoscopy images. The histogram analysis technique is examined for varying training set sizes from the set of 113 malignant melanomas and 113 benign dysplastic nevi images. RESULTS: Experimental results show improved discrimination capability for feature calculations focused in the interior lesion region. Recognition rates for malignant melanoma and dysplastic nevi as high as 87.7% and 74.9%, respectively, are observed for the color clustering ratio computed using the outer 75% uniformly distributed area with a 10% offset within the boundary. CONCLUSIONS: Experimental results appear to indicate that the melanoma color feature information is located in the interior of the lesion, excluding the 10% central-most region. The techniques presented here including the use of relative color and the determination of benign and malignant regions of the relative color histogram may be applicable to any set of images of benign and malignant lesions.     

Benign acral lesions showing parallel ridge pattern on dermoscopy

One of the recent advances in dermoscopy is the significance of parallel ridge pattern (PRP), which has 99% specificity in detecting both melanoma in situ and advanced melanoma on the acral volar skin. This review features exceptionally benign acral lesions showing PRP on dermoscopy. These benign lesions can be distinguished from malignant melanoma, because of the typical clinical history and associated symptoms. However, it is sometimes difficult for dermatologists to exclude malignant melanoma and a subsequent skin biopsy should be strongly recommended. These benign lesions include pigmentation due to a dye such as para-phenylenediamine, acral pigmented macules associated with Peutz-Jeghers syndrome, anti-cancer drug-induced hyperpigmentation on the volar skin, acral subcorneal hemorrhage and pigmented warts.     

Differentiation of common benign pigmented skin lesions from melanoma by high-resolution ultrasound

BACKGROUND: There are potential clinical benefits if non-invasive methods can be used to diagnose or exclude melanoma. OBJECTIVES: We investigated high-resolution ultrasound (HRU) as a potential non-invasive diagnostic aid for pigmented skin lesions. METHODS: Using a 20-MHz ultrasound B-scan imaging system interfaced to a computer, we assessed acoustic shadowing and entry echo line enhancement (EEE) for 29 basal cell papillomas (BCPs) and 25 melanomas. Acoustic shadowing was estimated by the dermal echogenicity ratio (DER), comparing mean echogenicity below the lesion with that of adjacent dermis. Histological features were scored independently. RESULTS: DER < 3 correctly distinguished melanoma from BCP with 100% sensitivity and 79% specificity. Specificity increased to 93% if the presence of EEE was included as a discriminator. Shadowing correlated most significantly with histological extent of hyperkeratosis (P < 0.0001). Consequently, this method falsely identified non-keratotic acanthotic BCP (n = 3) as melanoma. Highly significant differences between benign naevi (n = 15) and melanomas (n = 24) were found. The SD of retrolesional echogenicity was higher for naevi than melanomas (P < 0.0001), but such an analysis was poorly specific for the diagnosis of melanoma (30%). CONCLUSIONS: Overall, HRU has considerable potential as a high-performance screening tool to assist in the discrimination between BCP, but not benign naevi, and melanoma. In particular, it may be possible to exclude melanoma with 100% certainty in the differentiation of BCP from melanoma.     

Immunohistochemical expression of cyclooxygenage-2 in melanocytic skin lesions

Background Several reports have shown expression of cyclooxygenase‐2 (COX‐2) in malignant skin tumors. COX‐2 has also recently been reported as a marker of malignant melanoma (MM). Objective Our aim was to investigate whether there is a difference in the immunohistochemical expression of COX‐2 between malignant and benign melanocytic lesions of the skin. Methods We selected 40 archival cases of MM including 10 cases of superficial spreading melanoma, 10 of lentigo maligna melanoma, 10 of nodular melanoma, and 10 of acral lentiginous melanoma. For comparison, we also selected 35 benign melanocytic lesions, which included 15 nonatypical nevi and 10 atypical nevi. The remaining 10 cases were Spitz nevi. COX‐2 immunohistochemical staining was performed, and intensities were assessed quantitatively. Results The MM group and the benign melanocytic nevi group showed a highly statistically significant difference in the intensity of COX‐2 expression (P < 0.0001). Staining intensity in the dermal component of MM cases also showed a tendency to increase with increasing tumor depth. By contrast, the intensity of the dermal component in the melanocytic nevi group decreased with increasing depth as the nevus cells matured from type A to type C cells. No statistical difference was noted between the MM and Spitz nevi cases (P = 0.20). Conclusions Malignant melanoma shows stronger immunohistochemical expression of COX‐2 than benign melanocytic nevi. Although COX‐2 cannot be used alone to differentiate MM from melanocytic nevi, it may serve as an aid in the differential diagnosis of melanocytic skin lesions.     

A basis function feature‐based approach for skin lesion discrimination in dermatology dermoscopy images

Background: Skin lesion color is an important feature for diagnosing malignant melanoma. New basis function correlation features are proposed for discriminating malignant melanoma lesions from benign lesions in dermoscopy images. The proposed features are computed based on correlating the luminance histogram of melanoma or benign labeled relative colors from a specified portion of the skin lesion with a set of basis functions. These features extend previously developed statistical and fuzzy logic‐based relative color histogram analysis techniques for automated mapping of colors representative of melanoma and benign skin lesions from a training set of lesion images. Methods: Using the statistical and fuzzy logic‐based approaches for relative color mapping, melanoma and benign color features are computed over skin lesion region of interest, respectively. Luminance histograms are obtained from the melanoma and benign mapped colors within the lesion region of interest and are correlated with a set of basis functions to quantify the distribution of colors. The histogram analysis techniques and feature calculations are evaluated using a data set of 279 malignant melanomas and 442 benign dysplastic nevi images. Results: Experimental test results showed that combining existing melanoma and benign color features with the proposed basis function features found from the melanoma mapped colors yielded average correct melanoma and benign lesion discrimination rates as high as 86.45% and 83.35%, respectively. Conclusions: The basis function features provide an alternative approach to melanoma discrimination that quantifies the variation and distribution of colors characteristic of melanoma and benign skin lesions.     

Patient acceptance and diagnostic utility of automated digital image analysis of pigmented skin lesions

Background Computerized analysis of pigmented skin lesions may help to increase diagnostic accuracy for melanoma, help to avoid unnecessary procedures and reduce health care costs. Objectives We evaluated both the patient acceptance and diagnostic utility of such an analysis tool in a real clinical setting. Methods Two hundred nine consecutive patients (median age: 34 years, range: 2–73 years), who were concerned about a pigmented skin lesion, answered a questionnaire about their attitude towards computerized analysis and their confidence in the resulting findings. Using a dermoscopy analyser, their skin lesions (n = 219) were then grouped into the categories, benign, suspicious and malignant, and results were compared with those obtained by in‐person examination of dermato‐oncologic experts. Results More than half of the patients (n = 114) would accept the use of computer analysis for melanoma screening; although 16 (14.0%) patients would accept this method solely, 98 (86.0%) patients would prefer an additional in‐person examination by a dermatologist. Of the 219 pigmented skin lesions, the dermoscopic experts rated 171 (78.1%) as benign, 36 (16.4%) as suspicious and 12 (5.5%) as malignant, whereas computer analysis revealed 102 (46.6%) benign, 78 (35.6%) suspicious and 39 (17.8%) malignant lesions. At the expense of specificity (48.8%), the sensitivity of computerized analysis was excellent (100%) and equal to that of in‐person examination. Conclusions Most patients would accept computer analysis for melanoma screening, some of them even without reservations. However, due to a high rate of false positive computer assessments, it cannot be recommended as a screening tool at this time.     

The misdiagnosis of malignant melanoma

Despite the increasing awareness of malignant melanoma over the last 40 years, clinical diagnostic accuracy remains disappointing. Malignant melanoma can masquerade clinically as benign lesions (false negatives), and benign pigmented lesions can clinically simulate malignant melanoma (false positives). Histologic examination of pigmented lesions is therefore important to ensure proper diagnosis and treatment. We review many of the published reports of benign lesions mimicking melanoma and melanoma masquerading as other entities as well as present additional cases of clinical misdiagnoses of melanoma.     

Diagnostic and prognostic role of galectin 3 expression in cutaneous melanoma

Many of the histopathologic criteria used to diagnose melanoma overlap with atypical but otherwise benign naevi such as dysplastic or Spitz naevi. Galectin-3 is a member of the galectin gene family and is expressed at elevated levels in a variety of neoplastic cell types. The aim of the present study was to investigate the diagnostic value of galectin-3 expression compared with homatropine methyle bromide-45(HMB-45) (one of the established and widely used immunohistochemical melanocytic markers) together with assessment of its prognostic value in melanoma lesions. This study was carried out on 21 cases of melanoma and 20 benign pigmented naevi. Galectin-3 was expressed in all the examined benign and malignant melanocytic lesions. The nucleocytoplasmic pattern of galectin-3 appeared in malignant cases only with 42.86% sensitivity, 100% specificity, and 70.73% accuracy. This pattern tended to be associated with thick melanoma (P = 0.08) and reduced survival (P = 0.22). The intensity of galectin-3 assessed by H-score was significantly of higher values in malignant lesions compared with benign lesions (P < 0.0001). The best cut-off value for discrimination between benign and malignant melanocytic lesions was 295 with 95% sensitivity, 70% specificity, and 83% accuracy. The diagnostic power of galectin-3 in distinguishing between benign and malignant melanocytic lesions relies on the pattern and the intensity of its expression. The nucleocytoplasmic pattern of galectin-3 expression carries greater probability of a malignant phenotype and a poor prognostic impact on patients' outcome.     

Pre-diagnostic digital imaging prediction model to discriminate between malignant melanoma and benign pigmented skin lesion

Background: Malignant cutaneous melanoma is the most deadly form of skin cancer with an increasing incidence over the past decades. The final diagnosis provided is typically based on a biopsy of the skin lesion under consideration. To assist the naked-eye examination and decision on whether or not a biopsy is necessary, digital image processing techniques provide promising results.
Hypothesis and aims: The hypothesis of this study was that a computer-aided assessment tool could assist the evaluation of a pigmented skin lesion. Hence, the overall aim was to discriminate between malignant and benign pigmented skin lesions using digital image processing.
Methods: Discriminating algorithms utilizing novel well-established morphological operations and methods were constructed. The algorithms were implemented utilizing graphical programming (LabVIEW Vision). Verification was performed with reference to an image database consisting of 97 pigmented skin lesion pictures of various resolutions and light distributions. The outcome of the algorithms was analysed statistically with MATLAB and a prediction model was constructed.
Results/Conclusion: The prediction model evaluates pigmented skin lesions with regards to the overall shape, border and colour distribution with a total of nine different discriminating parameters. The prediction model outputs an index score, and by using the optimal threshold value, a diagnostic accuracy of 77% in discriminating between malignant and benign skin lesions was obtained. This is an improvement compared with the naked-eye analysis performed by professionals, rendering the system a significant assistance in detecting malignant cutaneous melanoma.     

Dermoscopy of skin lesions in two patients with xeroderma pigmentosum

BACKGROUND: Xeroderma pigmentosum (XP) is a rare disorder produced by a genetic defect in the repair of DNA damage caused by ultraviolet radiation. The early diagnosis of malignant skin tumours is crucial in the survival of patients with XP, but this is not easy even for experienced dermatologists due to the presence of a high number of actinic lesions. Dermoscopy is a new diagnostic method that increases the diagnostic accuracy for skin tumours. OBJECTIVES: To describe the clinical and dermoscopic features of different benign and malignant lesions [focusing on malignant melanoma, basal cell carcinoma (BCC) and benign melanocytic naevi] in two patients with XP. METHODS: Three dermatologists with experience in pigmented skin lesions and dermoscopy examined two siblings with XP over a period of 54 months. Diagnosis of skin tumours was obtained using clinical examination and dermoscopy with 10-fold magnification and digital images. All the tumours with criteria of malignancy were excised for further histopathological analyses. RESULTS: Multiple skin tumours showing some degree of pigmentation were detected in the patients. Clinical and dermoscopic examination allowed the discrimination of four melanomas (three of them in situ), 26 BCCs and five dysplastic naevi from other pigmented skin lesions. The features and parameters previously described for dermoscopy were shown to be appropriate for the recognition of tumours in our patients with XP. Generalized actinic lentigos were distinguished from BCCs by the presence of a delicate brown pigmented network. Fine vessels from poikiloderma were differentiated from the arborizing telangiectasia of BCC. CONCLUSIONS: The dermoscopic findings in the tumours were similar to those previously described in patients not affected by XP. Diagnosis by dermoscopic pattern analyses allowed a correct classification of malignant tumours in these cases.     

Impact of dermoscopy and short‐term sequential digital dermoscopy imaging for the management of pigmented lesions in primary care: a sequential intervention trial

Background Studies have shown the benign to malignant ratio of excised pigmented skin lesions is suboptimal in primary care. Objectives To assess the impact of dermoscopy and short‐term sequential digital dermoscopy imaging (SDDI) on the management of suspicious pigmented skin lesions by primary care physicians. Methods A total of 63 primary care physicians were trained in the use of dermoscopy and SDDI (interventions) and then recruited pigmented lesions requiring biopsy or referral in routine care by naked eye examination. They were then given a dermatoscope and the option of a SDDI instrument, and change of diagnosis and management was assessed. Results Following the use of the interventions on 374 lesions a total of 163 lesions (43·6%) were excised or referred, representing a reduction of 56·4%. Of the 323 lesions confirmed to be benign, 118 (36·5%) were excised or referred, leading to a reduction of 63·5% (P < 0·0005) in those requiring excision or referral. The baseline naked eye examination benign to melanoma ratio was 9·5 : 1 which decreased to 3·5 : 1 after the diagnostic interventions (P < 0·0005). Of the 42 malignant lesions included in the study (34 melanoma, six pigmented basal cell carcinoma and two Bowen disease) only one in situ melanoma was incorrectly managed (patient to return if changes occur) resulting in the correct management of 97·6% and 97·1% of malignant pigmented lesions and melanoma, respectively. Conclusions In a primary care setting the combination of dermoscopy and short‐term SDDI reduces the excision or referral of benign pigmented lesions by more than half while nearly doubling the sensitivity for the diagnosis of melanoma.     

Melanocytic nevi clinically simulating melanoma

Melanoma and other benign or malignant pigmented skin tumors can significantly overlap in their clinical and dermoscopical presentations. Thus, pigmented skin lesions may be misdiagnosed in a large number of cases. An extensive review of the published work provides numerous examples of benign lesions mimicking melanoma. Although a number of melanocytic nevi may have been identified as melanomas, information about their clinical appearance is limited. In this report, we present the clinical appearances of two melanocytic nevi on the vulva and the upper extremity that were difficult to diagnose clinically. Detecting melanoma at an early stage is of the utmost importance. However, more attention should be given to the diagnostic accuracy of benign pigmented skin lesions, which otherwise may be diagnosed and treated as melanoma.     

In vivo epiluminescence microscopy of pigmented skin lesions. I. Pattern analysis of pigmented skin lesions

The importance of recognizing early melanoma is generally accepted. Because not all pigmented skin lesions can be diagnosed correctly by their clinical appearance, additional criteria are required for the clinical diagnosis of such lesions. In vivo epiluminescence microscopy provides for a more detailed inspection of the surface of pigmented skin lesions, and, by using the oil immersion technic, which renders the epidermis translucent, opens a new dimension of skin morphology by including the dermoepidermal junction into the macroscopic evaluation of a lesion. In an epiluminescence microscopy study of more than 3000 pigmented skin lesions we have defined morphologic criteria that are not readily apparent to the naked eye but that are detected easily by epiluminescence microscopy and represent relatively reliable markers of benign and malignant pigmented skin lesions. These features include specific patterns, colors, and intensities of pigmentation, as well as the configuration, regularity, and other characteristics of both the margin and the surface of pigmented skin lesions. Pattern analysis of these features permits a distinction between different types of pigmented skin lesions and, in particular, between benign and malignant growth patterns. Epiluminescence microscopy is thus a valuable addition to the diagnostic armamentarium of pigmented skin lesions at a clinical level.     

Computerized Digital Image Analysis: An Aid for Melanoma Diagnosis

Both digital imaging and epiluminescence microscopy hold promise for improved early detection of cutaneous melanoma. Several centers have been actively working in these areas during the past decade. These experiences and preliminary work based on the image capture of 83 pigmented lesions at our center using a prototype digital imaging system (SKINVIEW) are described. This system is based, in part, on the analysis of lesional morphologic features, such as shape, border, and radii. Histopathologic correlation was matched against these features to assess the efficacy of diagnosis. At our center, these parameters alone were not sufficient to discriminate between benign and malignant lesions, in part, because the melanomas were, in general, early lesions and many of the nevi were sufficiently clinically atypical to require removal for discrimination from melanoma. In addition, technical improvements in the image capturing and processing mechanism are needed. Rapid progress in this area is anticipated.     

Combination of features from skin pattern and ABCD analysis for lesion classification

BACKGROUND/PURPOSE: It is known that the standard features for lesion classification are ABCD features, that is, asymmetry, border irregularity, colour variegation and diameter of lesion. However, the observation that skin patterning tends to be disrupted by malignant but not by benign skin lesions suggests that measurements of skin pattern disruption on simply captured white light optical skin images could be a useful contribution to a diagnostic feature set. Previous work using both skin line direction and intensity for lesion classification was encouraging. But these features have not been combined with the ABCD features. This paper explores the possibility of combing features from skin pattern and ABCD analysis to enhance classification performance. METHODS: The skin line direction and intensity were extracted from a local tensor matrix of skin pattern. Meanwhile, ABCD analysis was conducted to generate six features. They were asymmetry, border irregularity, colour (red, green and blue) variegations and diameter of lesion. The eight features of each case were combined using a principal component analysis (PCA) to produce two dominant features for lesion classification. RESULTS: A larger set of images containing malignant melanoma (MM) and benign naevi were processed as above and the scatter plot in a two-dimensional dominant feature space showed excellent separation of benign and malignant lesions. An ROC (receiver operating characteristic) plot enclosed an area of 0.94. CONCLUSIONS: The classification results showed that the individual features have a limited discrimination capability and the combined features were promising to distinguish MM from benign lesion.     

Predictive power of irregular border shapes for malignant melanomas

BACKGROUND/PURPOSE: The Irregularity Index is a measure of border irregularity from pigmented skin lesion images. The measure attempts to quantify the degree of irregularity of the structural indentations and protrusions along a lesion border. A carefully designed study has shown that the parameters derived from the Irregularity Index were highly correlated with expert dermatologists' notion of border shape. This paper investigates the predictive power of these parameters on a set of data with known histological diagnosis. METHODS: A set of 188 pigmented skin lesions (30 malignant melanomas and 158 benign lesions) was selected for the study. Their images were segmented and their border shapes were analysed by the Irregularity Index, producing four border irregularity parameters. The predictive power of these four parameters was estimated by a series of statistical tests. RESULTS: The mean values of the four border irregularity parameters were significantly different between the melanoma group and the benign lesion group. When using the four parameters to predict its disease status, the leave-one-out classification rate was 82.4%, and the area under the receiver operating characteristic curve was 0.77. A malignant melanoma was 8.9 times more likely to have an irregular border than a benign lesion. CONCLUSION: This study confirmed that border irregularity is an important clinical feature for the diagnosis of malignant melanoma. It also indicates that the computer-derived measures based on the Irregularity Index capture to certain extent the kind of irregularity which is exhibited by melanomas.