Clinicopathological correlation of pigmented skin lesions using dermoscopy

Dermoscopy (dermatoscopy, epiluminescence microscopy) is an additional measure for making the diagnosis of pigmented skin lesions more accurate. It enables the clinician to visualize features not discernible by the naked eye. By applying enhanced digital dermoscopy and a standardized gross pathology protocol to pigmented skin lesions, a precise clinicopathological correlation of relevant dermoscopic features can be made. Histological specimens of four pigmented skin lesions (melanoma in situ, Clark's nevus, Reed's nevus, seborrheic keratosis) were processed using a standardized gross pathology protocol and viewed along with the clinical photographs and digital dermoscopic images that were magnified and enhanced to better visualize the corresponding dermoscopic structures. Furthermore, measurements of dermoscopic structures using digital equipment were correlated with histometric findings. Our understanding of dermoscopic features, especially the broadened pigment network - a specific dermoscopic criterion for melanoma - was refined by this detailed case-by-case correlation. In addition, some not yet fully characterized dermoscopic features, such as black lamella, radial streaks, and exophytic papillary structures, were described in detail dermoscopically and histopathologically. Moreover, measurements of these dermoscopic features and the underlying histological structures were found to be similar. Linking dermoscopy more closely with cutaneous pathology may help refine the definitions and diagnostic criteria of pigmented skin lesions for dermatologists as well as dermatopathologists.     

Dermoscopic findings in Laugier-Hunziker syndrome

BACKGROUND: Laugier-Hunziker syndrome (LHS) is a rare, acquired mucocutaneous hyperpigmentation often associated with longitudinal melanonychia. The clinical behavior of mucocutaneous pigmented lesions ranges from benign to highly malignant. Therefore, in most cases, the clinical diagnosis should be confirmed by further diagnostic methods. Dermoscopy is a noninvasive technique that has been used to make more accurate diagnoses of pigmented skin lesions. Nevertheless, to our knowledge, the dermoscopic features of the pigmented lesions in LHS have not been described previously. Herein, we report a case of LHS together with its dermoscopic features. OBSERVATIONS: The clinical examination revealed macular hyperpigmentation on the oral and genital mucosa, conjunctiva, and palmoplantar region together with longitudinal melanonychia. Dermoscopic examination of mucosal lesions on the patient's lips and vulva revealed a parallel pattern. Longitudinal homogeneous pigmentation was observed on the toenails. The pigmented macules on the palms and the sole showed a parallel furrow pattern. A skin biopsy sample taken from the labial lesion was compatible with a diagnosis of mucosal melanosis. CONCLUSIONS: By means of this case report, the dermoscopic features of the pigmented lesions in LHS are described for the first time, which facilitates diagnosis with a noninvasive technique. Future reports highlighting the dermoscopic features of this syndrome may simplify the diagnosis of LHS, which is thought to be underdiagnosed.     

The seven features for melanoma: a new dermoscopic algorithm for the diagnosis of malignant melanoma.

The clinical diagnosis of melanoma has a mean sensitivity of 67%, dermoscopy or dermatoscopy is a non invasive technique which improves this sensitivity. Our purpose was to create a simple dermoscopic method for the diagnosis of melanoma useful in daily office practice. For this reason a training set of 218 cutaneous pigmented lesions was used and scored for 16 dermoscopic features: for each feature sensitivity, specificity and statistical significance were evaluated. The results were used to create a simple dermoscopic diagnostic method of only seven dermoscopic features (7FFM). The method was used to evaluate a test set of 713 pigmented skin lesions consecutively observed. The diagnostic dermoscopic method developed gave a sensitivity of 94.6%, a specificity of 85.5% and an efficiency of 87.6%. Our method improves the sensitivity in the diagnosis of melanoma and can be used for the screening of pigmented skin lesions.     

Dermoscopy in general dermatology

Dermoscopy improves the diagnostic accuracy in the clinical evaluation of pigmented skin lesions, but it is also useful for the assessment of vascular structures that are not visible to the naked eye. As a consequence, dermoscopy has been employed more and more for the differential diagnosis of nonpigmented skin disorders, including tumors but also inflammatory and infectious diseases. This article provides a review of the dermoscopic features seen in various nonpigmented tumoral and nontumoral skin lesions as well as the dermoscopic criteria used for monitoring skin reactions to various treatments.     

Key points in dermoscopic diagnosis of basal cell carcinoma and seborrheic keratosis in Japanese

Basal cell carcinoma (BCC) and seborrheic keratosis (SK) are representative pigmented skin tumors, and they are differentiated as non-melanocytic lesions in the two-step dermoscopy algorithm proposed by the Consensus Net Meeting on Dermoscopy. Because most BCC in Japanese patients are pigmented clinically, dermoscopy plays an important role in their differential diagnosis. The dermoscopic criteria for BCC include the lack of a pigment network and the presence of at least one positive feature for BCC, such as large blue-gray ovoid nests, multiple blue-gray globules, leaf-like areas, spoke wheel areas, arborizing vessels and ulceration. Whereas various dermoscopic features are seen in SK, comedo-like openings, milia-like cysts, and fissures and ridges are especially important features. It is necessary for clinicians to consider the pathological conditions causing the dermoscopic features of BCC and SK. In addition, the sensitivity and specificity of each feature should be taken into consideration to ensure an accurate dermoscopic diagnosis.     

Dermoscopic features of cutaneous local recurrent melanoma

We describe for the first time the dermoscopic features of cutaneous recurrent melanoma including a globular pattern and a diffuse nonhomogeneous pigmentation. These findings greatly differ from those observed in primary cutaneous melanoma and should be considered in the dermoscopic differential diagnosis of pigmented skin lesions.     

Dermoscopic features of actinic keratosis and follow up with dermoscopy: A pilot study

Actinic keratosis (AK) is a common precursor of sun‐related squamous cell carcinoma. AK is difficult to be differentiated from other malignancies with the naked eyes. Dermoscopic features of AK were previously described in some studies, but not extensively investigated. We investigated the dermoscopic features of AK in Asians and assessed dermoscopy as a post‐treatment monitoring tool of AK. We retrospectively examined 34 AK lesions which had been diagnosed by histology. The changes of dermoscopic features and histopathological findings were assessed in all these lesions before and after treatment. Before treatment, 18 lesions were pigmented and 16 lesions were non‐pigmented AK dermoscopically. The frequent dermoscopic features of AK were keratin/scales (79.4%), red pseudonetwork (73.5%), targetoid‐like appearance (55.9%), rosette sign (38.2%) and absent fissures/ridges, crypts and milia‐like cysts. All the lesions had been treated with either photodynamic therapy, cryotherapy or 5% imiquimod cream. After treatment, dermoscopic features of 33 AK lesions were decreased or disappeared, and skin biopsies confirmed that atypical keratinocytes disappeared. One lesion showed accentuated and new dermoscopic features after treatment, and skin biopsy also showed progressing squamous cell carcinoma. In conclusion, scales, red pseudonetwork, targetoid‐like appearance and rosette sign were common dermoscopic findings of AK in Asians. In most cases, the treatment response correlated with the changes in dermoscopic features. These findings suggest that dermoscopy is a useful tool to monitor AK.     

Key points in dermoscopic differentiation between early acral melanoma and acral nevus

Acral skin is the most prevalent site of malignant melanoma in non-Caucasian populations. On acral skin, other various kinds of pigmented lesions are also detected. Particularly, melanocytic nevus is commonly seen on acral volar skin; approximately 10% of Japanese have a nevus on their soles. Prognosis of acral melanoma is still generally poor because of delayed detection in the advanced stages. To improve the prognosis, early detection is essential. Early acral melanoma is seen as a brownish macule, which is clinically quite similar to acral nevus. Therefore, clinicians often face a dilemma when they see a pigmented macule on acral volar skin. Introduction of dermoscopy was a great epoch in this field. Pigmentation pattern on dermoscopy is completely opposite between early acral melanoma and acral nevus; pigmentation on the ridges of the surface skin markings is detected in early acral melanoma, whereas pigmentation along the furrows of the skin markings is seen in acral nevus. We termed these dermoscopic patterns the parallel ridge pattern and the parallel furrow pattern, respectively. These features are highly helpful in the differentiation between the two biologically distinct entities. The sensitivity and specificity of the parallel ridge pattern in diagnosing early acral melanoma is 86% and 99%, respectively. However, we must be aware that dermoscopic features in acral nevus sometimes mimic the parallel ridge pattern and that other conditions also could show dermoscopic features similar to the parallel ridge pattern. In this review article, we summarize key points of the dermoscopic diagnosis of early acral melanoma and then describe the three-step algorithm for the management of acral melanocytic lesions, which surely aids us in effectively detecting early acral melanoma and in reducing unnecessary resection of benign nevus.     

Dermoscopy of Bowen's disease

BACKGROUND: Dermoscopy improves the diagnostic accuracy in pigmented skin lesions, but it is also useful in the evaluation of nonpigmented skin tumours as it allows the recognition of vascular structures that are not visible to the naked eye. Bowen's disease (BD) or squamous cell carcinoma in situ is usually nonpigmented, but may also rarely be pigmented. Objective To describe the dermoscopic features in a series of pigmented and nonpigmented BD. METHODS: Dermoscopic images of 21 histopathologically proven BD were evaluated for the presence of various dermoscopic features. Each lesion was photographed using the Dermaphot (Heine Optotechnik, Herrsching, Germany), at 10-fold magnification, and the colour slides were scanned to digital format using a Kodak Photo CD system. RESULTS: The majority of cases of BD revealed a peculiar dermoscopic pattern characterized by glomerular vessels (90%) and a scaly surface (90%). In addition, in pigmented BD small brown globules regularly packed in a patchy distribution (90%), and structureless grey to brown pigmentation (80%) were observed. CONCLUSIONS: Dermoscopy can be helpful for diagnosing BD because of the presence of repetitive morphological findings such as glomerular vessels and a scaly surface. In pigmented BD, small brown globules and/or homogeneous pigmentation can be seen as well.     

Typical dermoscopic patterns of benign melanocytic nevi

Dermoscopy often is an effective diagnostic tool for differentiating benign and malignant pigmented skin lesions. The observed dermoscopic structures and patterns of lesions provide valuable sources of information that are not accessible by routine clinical examination. Recognition and interpretation of these dermoscopic structures and patterns require training and experience. Mentioned here are some fundamental guidelines for differentiating malignant and benign lesions. Some of the classic patterns associated with a list of benign melanocytic nevi also have been illustrated. Additional research is needed to identify other patterns of these benign lesions. More importantly, analysis of the prevalence of various patterns associated with the various benign lesions will be helpful to clinicians having the responsibility of making in vivo diagnoses of benign compared with malignant melanocytic neoplasms.     

Histopathologic correlates of dermoscopic criteria

The correct interpretation of dermoscopic features requires an understanding of the corresponding histopathologic correlates. This articles addresses the importance of performing an exact dermoscopic-pathologic correlation when evaluating pigmented lesions of the skin. The histopathologic structures underlying most dermoscopic criteria are extensively described.     

Dermoscopic features of actinic keratosis

Actinic keratosis (AK) is a keratinocytic neoplasm that typically develops on sun‐damaged skin of elderly individuals. Only a few reports so far have described the dermoscopic diagnostic features of AK, mainly focusing on facial non‐pigmented AKs. A typical feature of facial non‐pigmented AK is a composite pattern named “strawberry pattern”, characterized by a background erythema/red pseudonetwork consisting of unfocused, large vessels located between the hair follicles, associated with prominent follicular openings surrounded by a white halo. Dermoscopic characteristics of pigmented AK on the face include multiple slate‐gray to dark‐brown dots and globules around the follicular ostia, annular‐granular pattern and brown to gray pseudonetwork. Recognizing specific dermoscopic features of AK can be useful in guiding the clinician in the differential diagnosis of AK with melanocytic skin lesions such as LM and non‐melanocytic lesions. Histopathologic examination should be performed whenever clinical and/or dermoscopic differential diagnosis is inconclusive.     

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.     

Pre-operative diagnosis of pigmented skin lesions: in vivo dermoscopy performs better than dermoscopy on photographic images

BACKGROUND: Epiluminescence microscopy (ELM) (dermoscopy, dermatoscopy) is a technique for non-invasive diagnosis of pigmented skin lesions that improves the diagnostic performance of dermatologists. Little is known about the possible influence of associated clinical features on the reliability of dermoscopic diagnosis during in vivo examination. OBJECTIVE: To compare diagnostic performance of in vivo dermoscopy (combined clinical and dermoscopic examination) with that of dermoscopy performed on photographic slides (pure dermoscopy). DESIGN: This case series comprised 256 pigmented skin lesions consecutively identified as suspicious or equivocal during examination in a general dermatological clinic. Clinical examination and in vivo dermoscopy were performed before excision by two trained dermatologists. The same observers carried out dermoscopy on photographic slides at a later time, and these three diagnostic classifications were reviewed together with the histological findings for the individual lesions. This was carried out in a university hospital. RESULTS: In vivo dermoscopy performed better than dermoscopy on photographic slides for classification of pigmented skin lesions compared with histological diagnosis, and both performed better than general clinical diagnosis. In vivo dermoscopic diagnosis of melanoma showed 98.1% sensitivity, 95.5% specificity and 96.1% diagnostic accuracy while dermoscopic diagnosis of melanoma on photographic slides was less reliable with 81.5% sensitivity, 86.7% specificity and 85.2% diagnostic accuracy. In particular, diagnosis of melanoma based on photographic slides led to nine false negative cases (three in situ, six invasive; thickness ranges 0.2-1.5 mm). CONCLUSIONS: In vivo dermoscopy, i.e. combined clinical and dermoscopic examination, is more reliable than dermoscopy on photographic slides. In clinical practice, therefore, in vivo dermoscopy cannot be considered independent from associated clinical characteristics of the lesions, which help the trained observer to reach a more precise classification. This may have implications on the reliability of ELM diagnosis made by an observer not fully trained in the clinical diagnosis of pigmented skin lesions or by a remote observer during digital ELM teleconsultation.     

Características dermatoscópicas del poroma ecrino

Eccrine poroma is a benign adnexal neoplasm that clinically may mimic malignant skin tumors such as squamous cell carcinoma and amelanotic melanoma. The dermoscopic features of pigmented and nonpigmented eccrine poroma have recently been described. We present 2 cases of eccrine poroma, with their dermoscopic features. The lesions were characterized by multiple red lacunes and a polymorphous vascular pattern in both cases. Dermoscopy can improve the clinical diagnosis of this benign adnexal skin tumor.     

Melanocytic aggregation in the skin: diagnostic clues from lentigines to melanoma

Pigmented skin lesions are among the most common skin lesions. Among them, melanocytic proliferations are morphologically diverse and their behavior may be difficult to discern with certainty. Researchers must be able to distinguish melanocytic from nonmelanocytic pigmented skin lesions and, in particular, benign from malignant lesions. The majority of these lesions can be diagnosed with ease; however, a minority of cases is difficult and have potential for error. The authors have systematically analyzed the clinical and dermoscopic features of melanocytic skin lesions, so as to increase in vivo diagnostic accuracy.     

Evaluation of dermoscopic and histopathologic features and their correlations in pigmented basal cell carcinomas

BACKGROUND: Because of their clinical similarities, pigmented basal cell carcinomas (BCCs) can be confused with melanocytic pigmented lesions especially with melanoma. Since special dermoscopic features have been described for pigmented BCCs, dermoscopy is accepted as a useful tool for the diagnosis of pigmented BCCs. OBJECTIVE: To investigate dermoscopic and corresponding histopathologic features of BCCs and to evaluate their correlations in pigmented BCCs. METHODS: In this study, 32 pigmented BCCs in 30 patients whose diagnoses were confirmed with clinical and histopathologic features were included. Before the histopathologic evaluation, the lesions were analysed for dermoscopic features. Histopathologic correlations of dermoscopic features of BCCs and the localization of pigment accumulation in tumour mass were investigated. RESULTS: In addition to ulceration, large grey-blue ovoid nests, multiple grey-blue globules, maple leaf areas and arborizing telangiectasia; dermoscopically yellow-brown, whitish-yellow, and black-dark brown colour showed statistically significant correlation with their histopathologic counterparts (P < 0.05). Whitish veil, which is among dermoscopic features of BCCs, did not show significant correlation with its histopathologic counterpart (P > 0.05). It was histopathologically determined that pigmentation is found within the tumour mass as well as in the tumour stroma and in the hyperplastic epidermal melanocytes. CONCLUSIONS: Ulceration, large grey-blue ovoid nests, multiple grey-blue globules, maple leaf-like areas and arborizing telangiectasia, which are specific dermoscopic features for the diagnosis of pigmented BCC, were found to correlate with their histopathologic counterparts. In conclusion, dermoscopy can be described as a valuable tool for the diagnosis of pigmented basal cell carcinomas.     

Dermoscopic features of Bowen’s disease in Asians

Background Previously, dermoscopic features of Bowen’s disease (BD) were extensively investigated in two studies, but there were some discrepancies. The dispute necessitated a further study concerning the dermoscopic features of BD. Objective To describe the dermoscopic features of BD in Asians and to assess dermoscopy as a post‐treatment monitoring tool of BD. Materials and methods Dermoscopic examinations of histopathologically diagnosed 26 BD lesions were performed to evaluate for the presence of various dermoscopic features. In addition, the correlating changes of dermoscopic features and histopathological results before and after treatments were assessed in five patients with BD. Results Dermoscopically, 10 lesions were pigmented and 16 lesions were non‐pigmented. The most frequent dermoscopic findings of BD were vascular structures (96%) and a scaly surface (96%). Among vascular structure, glomerular vessels were most frequently observed (77%). The other vascular structures in our study were linear irregular vessels, dotted vessels, polymorphous/atypical vessels and arborizing vessels. Among five patients who had been treated with either photodynamic therapy or 5% imiquimod cream, four patients revealed disappearance of dermoscopic vascular structures, but one patient showed remaining vascular structures after treatment. Skin biopsy from treated lesions disclosed clearance of BD in four patients who had no vascular structures but remaining BD in the patient whose dermoscopic finding displayed no disappearance of vascular structures. Conclusions Vascular structures, especially glomerular vessels plus a scaly surface, were common dermoscopic findings of BD in Asians. In addition, existence of dermoscopic vascular structures after treatment appears to be associated with residual disease.     

Dermoscopy

First, a brief introduction about types of dermoscope and an explanation on the theory of dermoscopy are provided. Second, some introduction on the difference of dermoscopic pictures between benign and malignant neoplasm is given. Basically, benign lesions tend to show symmetrical dermoscopic structures and colors, whereas malignant lesions have a tendency to present irregular and atypical dermoscopic structures. Third, the relationship between dermoscopic images and anatomical structures will be shown. Acral melanocytic lesions have site-specific dermoscopic patterns, namely parallel furrow pattern or parallel ridge pattern. These parallel patterns are due to different distribution of benign and malignant melanocytes. Benign melanocytes (nevus cells) are mainly found on the tips of crista profunda limitans and supply melanin granules to the furrows of stratum corneum, making a parallel furrow pattern. To the contrary, melanoma cells proliferate mainly on the tips of crista profunda intermedia or rather diffusely and randomly, and supply melanin granules irregularly and diffusely to the ridges of stratum corneum, having parallel ridge pattern. Fourth, the global features of dermoscopic findings are described respectively with definitions of the technical terms. To analyze dermoscopic structures, it is easier to look at global features first and local features next. Basic global features include reticular, globular, cobblestone, homogeneous, starburst and parallel patterns. If a given dermoscopy image has two patterns, the more prominent pattern might be chosen. If it has more than three dermoscopic patterns, then multi-component pattern is the reasonable selection. If there are no particular dermoscopic structures, then the unspecific pattern will be selected. Finally, some comments on the relationship between dermoscopy and dermatopathology are given briefly. It is always useful to imagine dermatopathological features when examining a dermoscopic image. There are considerable relations between dermoscopy and dermatopathology.     

Dermoscopy patterns of fibroepithelioma of pinkus

BACKGROUND: Fibroepithelioma of Pinkus (FeP) is a rare variant of basal cell carcinoma that may clinically mimic a number of benign skin tumors. While the dermoscopic features of basal cell carcinoma have been studied extensively, little is known about the dermoscopic features of FeP. OBSERVATIONS: Retrospective evaluation of clinical records and digital clinical dermoscopic images of 10 histopathologically proved FePs (6 nonpigmented and 4 pigmented) was performed. Clinically, no FeP was correctly identified and, in half of all patients, a clinical differential diagnosis of purely benign skin lesions was made. Dermoscopy enabled the correct diagnosis in 9 of 10 FePs, based on the presence of fine arborizing vessels, either alone or associated with dotted vessels, and white streaks (in 100%, 70%, and 90% of lesions, respectively). In the 4 pigmented FePs, a structureless gray-brown area of pigmentation and variable numbers of gray-blue dots were observed, in addition. CONCLUSIONS: Dermoscopy is helpful in diagnosing FeP and in differentiating this variant of basal cell carcinoma from other benign skin tumors commonly included in the clinical differential diagnosis. This presumes, however, that dermoscopy is used as a first-line examination for all skin lesions, not only for those that are clinically suspect.