Modified ABC-point list of dermoscopy: A simplified and highly accurate dermoscopic algorithm for the diagnosis of cutaneous melanocytic lesions

BACKGROUND: The use of dermoscopy (epiluminescence microscopy, surface microscopy, dermatoscopy) improves clinical diagnostic sensitivity by 10% to 27%, particularly achieved by different algorithms or scores. OBJECTIVE: We sought to develop a simplified and highly accurate dermoscopic-point list for cutaneous melanocytic lesions. METHOD: We studied consecutive patients with suspicious melanocytic lesions, which were excised and histopathologically examined at our institution. On the basis of the ABCD rule of Stolz, Menzies score, and the modified ABCD rule of Kittler, a simplified ABC-point list was developed. Simple points were given for the following: asymmetry of outer shape (A) or differential structures inside the lesion in at least 1 axis ((A)); the abrupt cutoff of network at the border in at least one quarter of circumference (B); 3 or more colors (C); 3 or more differential structures (D); or noticed change (evolution) in the last 3 months (E). Using 20-fold magnification of computer dermoscopy, the sensitivity, specificity, and diagnostic accuracy were examined in 269 cutaneous melanocytic lesions. Of these, 84 (31.2%) were cutaneous melanomas. Also, the sensitivity, specificity, and diagnostic accuracy were investigated with a 7-point checklist and the 7 features for melanoma. RESULTS: With the ABC-point list for the diagnosis of cutaneous melanoma, sensitivity was 90.5%, specificity was 87%, and diagnostic accuracy was 88.1%, confirmed by cross-validation. The ABCD rule resulted in 90.5%, 72.4%, and 78.1%; Menzies score in 95.2%, 77.8%, and 83.3%; 7-point checklist in 90.5%, 87%, and 88.1%; and 7 features for melanoma in 94%, 74.6%, and 80.7%, respectively, CONCLUSIONS: The ABC-point list is simpler than the already established algorithms. Despite its simplicity, a high sensitivity, specificity, and diagnostic accuracy was achieved. This simplified approach in dermoscopic diagnostics may contribute to further spread and enable to learn and use this method more easily.     

Diagnostic imaging of melanocytic skin tumors

BACKGROUND: In tissue counter analysis, digital images are dissected into subregions (elements), and the digital information in each element is used for statistical analysis. The aim of this study was to test the applicability of tissue counter analysis and CART (Classification and Regression Tree) to the diagnostic discrimination of benign common nevi and malignant melanoma in dermatopathology. METHODS: Two hundred cases each of benign nevi and malignant melanoma were consecutively sampled. CART analyses of background versus tissue elements, cellular versus 'other' tissue elements and benign versus malignant cellular elements were performed. For diagnostic assessment, only the percentage of cellular elements suggestive for malignancy in each case was used. RESULTS: CART analysis led to a correct classification of 99% of background versus tissue elements, 96% of cellular versus 'other' tissue elements and 79.1% of benign versus malignant cellular elements. When the percentage of cellular elements suggestive for malignancy in each case was evaluated, 29.5 +/- 14% (range 4.1-62.4) 'malignant' elements were found in benign nevi (n = 200), in contrast to 75.9 +/- 13.9% (range 32.8-97.3) in melanoma (n = 200; z =-16.72, p < 0.001). It turned out that a threshold level of 52.51% provides a correct classification of 192 nevi and 186 melanoma out of 200 each (specificity 96%, sensitivity 93%, positive predictive value 95.9%). CONCLUSIONS: Tissue counter analysis combined with CART may be a useful method for diagnostic purposes in histopathology.     

Morphometric diagnosis of melanocytic skin tumors

Checking consecutively sampled routine sections of 206 melanocytic lesions with a maximum vertical diameter of at least 1 mm (133 benign dermal nevi, 20 Spitz's nevi, 53 primary malignant melanomas), we measured the morphometric features of at least 60 nuclei each from the superficial and the deep dermal tumor portion using a computer-assisted interactive image analysis system. Furthermore we calculated the so-called maturation parameter (MP) in each case as the ratio of the mean nuclear area in the deep portion and the superficial portion. When we compared the results with those obtained in a training set, we found that the lowest evidence for the discrimination of benign and malignant melanocytic lesions resulted from the application of the mean values of the nuclear area in the superficial layer (efficiency = 62.1%). The efficiency was higher when we used the mean values of the nuclear area in the deep layer (96.1%) and the maturation parameter (85.4%). By applying the mean nuclear area in the deep portion and the maturation parameter simultaneously, we gained the highest efficiency, specificity, and sensitivity for the distinction between benign dermal nevi and malignant melanomas (0.968, 0.955, 1) as well as for the distinction between Spitz's nevi and malignant melanomas (0.986, 0.950, 1). Our study shows that morphometry provides reliable diagnostic results in routinely sampled melanocytic skin tumors.     

常见非黑素细胞性皮肤肿瘤皮肤镜特征与组织病理表现的对应关系专家共识

【摘要】 皮肤镜在皮肤病诊疗中的应用日益广泛,大多数皮损皮肤镜下结构特征与组织病理学表现有对应关系,因此皮肤镜可作为皮肤病临床和病理之间联系的桥梁。本共识详细阐述非黑素细胞性皮肤肿瘤的皮肤镜特征和组织病理的对应关系,希望有助于皮肤镜被更为规范、高效、精准地应用,为临床诊断和治疗决策提供有价值的临床信息。     

Clinical and dermoscopic features of congenital melanocytic nevi

BackgroundCongenital melanocytic nevi (CMN) are nevomelanocytic nevi which are present at birth. In this study, we set out to determine the clinical and dermoscopic properties of CMN.MethodsA total of 239 lesions were diagnosed as CMN. Dermoscopic properties were noted. Age, sex, nevus location and nevus size of the patients were also collected from the patient records.ResultsA total of 239 lesions were diagnosed as CMN in 239 patients (age ranged from 1 month to 63 years (20.79 ± 13.76 yr); 114 [47.7%] males and 125 [52.3%] females). Most of the lesions were medium-sized CMN, followed by small and large ones. The most common localization was upper extremities (23.8%), followed by head and neck, back, and lower extremities respectively. Dark brown was the most common colour seen in dermoscopy (115 patients, 48.1%), followed by light brown (69 patients, 28.9%) and black (55 patients, 23%) respectively. The most common dermoscopic findings of CMN was hair follicles followed by dots (70%) and perifollicular hypopigmentation (51%).ConclusionsOur study describes the normal clinical and dermoscopic features of CMN. It should be kept in mind that, CMNs are quite common lesions, and melanomas can arise from them. Knowing and being familiar with the normal properties of these common nevi will help us determine whether a nevus is suspicious or not.     

Digital computer analysis of dermatoscopical images of 260 melanocytic skin lesions; perimeter/area ratio for the differentiation between malignant melanomas and melanocytic nevi

BACKGROUND: Digital computer analysis of dermatoscopical images has been reported to facilitate the differential diagnosis of pigmented skin lesions in recent years. OBJECTIVE: The aim of our study was to perform digital computer analysis of a set of different melanocytic lesions and compare the objective results. METHODS: The set of 260 melanocytic lesions (150 excised difficult cases (46 melanomas, 47 atypical nevi, 57 common nevi and 110 unexcised common nevi) was automatically analysed by the digital dermatoscopical system microDERM. We searched for differences in asymmetry, size, compactness and colour distribution. Perimeter/area ratio was calculated. RESULTS: The perimeter/area ratio was detected as the most important criterion for differentiation between malignant and benign melanocytic lesions (sensitivity 91.3% and specificity 90.7% for malignant melanomas vs. all benign nevi; sensitivity 91.3% and specificity 80.8% for melanomas vs. clinically atypical nevi). Differences in size of the lesion, shape and asymmetry of colour were found and statistically verified. Using step-wise logistic regression the formula for calculation of probability of malignant nature of every analysed lesion was constructed. CONCLUSION: The perimeter/area ratio is a simple parameter for the differential diagnosis of melanocytic skin lesions.     

Melanotic pigmentation in excision scars of melanocytic and non-melanocytic skin tumors

The appearance of pigmented lesions in melanoma surgical scars is a frequent finding that in some instances may cause confusion with a melanoma persistence. Nevertheless, only a few papers have dealt with this subject in the dermatologic literature. The melanoma surgical scars of 60 consecutive patients were reviewed with special attention to the presence of pigmentation and its clinical characteristics. Simultaneously, the scars of 60 consecutive patients who had been subjected to excision of a non-melanoma skin tumor were also studied. Biopsies were performed in representative clinical cases of pigmented lesions arising on the scars of both groups, as well as in non-pigmented scars, and processed for hematoxylin-eosin and immunohistochemistry. Pigmented lesions were present in a similar percentage in both groups (30% in melanoma scars (18/60) and 25% in non-melanoma scars (15/60)). Clinically, three types of clinical pigmentation were observed: lentigine-like lesions; pigmented streaks in scars after direct closure; and diffuse pigmentation in grafts. Histologically, two patterns emerged: one with lentiginous epidermal hyperplasia, hyperpigmentation, and a normal or moderately increased number of melanocytes; and a second one characterized by melanocytic hyperplasia of a variable degree. The scar process itself, irrespective of the tumor excised, seems to be responsible for the pigmentation. We suggest the existence of an induction process of scar tissue acting on melanocytes of the overlying epidermis.     

Tubulin expression in melanocytic skin tumors. An immunohistochemical study

The microtubulus system as a part of the cellular cytoskeleton contributes to cell movement. Microtubulus assembly and disassembly is considered to be essential for tumor invasion and serves as a target for tumor chemotherapy. Using immunohistochemical methods, we investigated the distribution of tubulin in normal skin and 34 melanocytic skin tumors. In normal skin, tubulin was strongly expressed in dermal nerves, melanocytes, fibroblasts within the papillary dermis and in myoepithelial cells. In melanocytic skin tumors, nevus cells and melanoma cells stained positive, particularly at the periphery of the lesions, where there were single cells and small nests. The main difference between benign and malignant melanocytic tumors was found in the stromal cells: In melanocytic nevi, the stromal fibroblasts were entirely tubulin negative; whereas, adjacent to the invasive edge in primary and metastatic malignant melanoma, the stroma fibroblasts were strongly positive. Our results show that tubulin is regularly expressed in melanocytic skin tumors and may serve as a prerequisite for cell movement. The pronounced expression of tubulin in fibroblasts surrounding malignant melanocytic skin lesions reflects a stromal alteration that might contribute to tumor invasion.     

Key points in dermoscopic differentiation between lentigo maligna and solar lentigo

A clinical diagnosis of lentigo maligna at an early stage is often difficult even for experienced dermatologists. Differential diagnoses would include solar lentigo, early lesions of seborrheic keratosis, lichen planus-like keratosis, pigmented actinic keratosis and melanocytic nevus. Dermoscopy has been shown to have higher diagnostic accuracy, especially in the diagnosis of pigmented skin lesions, in the past two decades. To aim of the present study was to review the diagnostic key points on dermoscopy in the published work to differentiate lentigo maligna from other differential diagnoses and reassess these important features on dermoscopy for specificity by describing the findings in detail. Diagnostic key points for lentigo maligna/lentigo maligna melanoma on dermoscopy are asymmetrical pigmented follicular openings, rhomboidal structures, annular-granular structures and gray pseudo-network. Lentigo maligna, at first, seems to occur as asymmetrical pigmented follicular openings and/or annular-granular structures, then expand and develop into the rhomboidal structures. Annular-granular structures and gray pseudo-network seem to be observed also in regressive areas of solar lentigo/initial seborrheic keratosis, lichen planus-like keratosis and pigmented actinic keratosis. The four important criteria on dermoscopy for the diagnosis of lentigo maligna have been reviewed, and the former two criteria seem to be more specific, but it might be difficult to recognize these findings without misinterpretation. The latter two seem to be not so specific as they would also be demonstrated in other pigmented epidermal lesions, although the distribution of the structures in these disorders would be inclined to be more homogeneous than that of lentigo maligna.     

Diagnostic tissue elements in melanocytic skin tumors in automated image analysis

In tissue counter analysis, digital images are divided into subregions (elements), and the digital information in each element is used for statistical analysis. In this study, we assessed the morphologic details of tissue elements that have turned out to be of diagnostic significance in the discrimination of benign common nevi and malignant melanoma. After creation of a data set based on a total of 12,000 cellular elements obtained from 100 benign common nevi and 100 malignant melanomas, classification and regression tree (CART) analysis was performed to differentiate between cellular elements of nevi and melanoma. In a second step, the slides were re-evaluated by the decision tree; cellular elements suggestive either for benign common nevi or for malignant melanoma were highlighted on zoomed images of the whole sections, and the individual elements were displayed in galleries. Eight groups of elements (so-called terminal nodes) seemed to indicate benign common nevi, whereas seven terminal nodes were suggestive for malignant melanoma. The elements of nodes suggestive for benign nevi largely contained nevus cells with amphiphilic cytoplasm intermingled with fibrillary material, whereas the elements of the nodes suggestive for malignant lesions often showed hyperchromatism, perinuclear halos, heavy pigmentation, or a lymphohistiocytic infiltrate. Tissue counter analysis automatically detects tissue elements that are in accordance with morphologic criteria used in conventional histopathology for diagnostic discrimination.     

Comparative performance of 4 dermoscopic algorithms by nonexperts for the diagnosis of melanocytic lesions

OBJECTIVE: To assess 4 dermoscopy methods in a nonexpert setting. DESIGN: Sixty-one medical practitioners, mainly primary care physicians in Australia, were trained in 4 dermoscopy algorithms. Participants then assessed macroscopic and dermoscopic images of 40 melanocytic skin lesions. Each of the dermoscopic images was assessed with pattern analysis, the 7-point checklist, the ABCD rule, and the Menzies method. RESULTS: The Menzies method showed the highest sensitivity, 84.6%, for the diagnosis of melanoma, followed by the 7-point checklist (81.4%), the ABCD rule (77.5%), pattern analysis (68.4%), and assessment of a macroscopic image (60.9%). Pattern analysis and assessment of the macroscopic image showed the highest specificity, 85.3% and 85.4%, respectively. The ABCD rule showed a specificity of 80.4%; the Menzies method, 77.7%; and the 7-point checklist, 73%. The Menzies method had a diagnostic accuracy of 81.1%; the ABCD rule, 79.0%; the 7-point checklist, 77.2%; pattern analysis, 76.8%; and clinical assessment, 73.2%. CONCLUSIONS: All algorithms performed well in the hands of relatively inexpert practitioners who had undertaken self-guided training provided on compact disc. The Menzies method showed the highest diagnostic accuracy and sensitivity for melanoma diagnosis and was preferred by study participants.