Histological features used in the diagnosis of melanoma are frequently found in benign melanocytic naevi

Primary non-cutaneous melanomas of the head and neck: Case series and review of the literature

Primary non-cutaneous melanoma is a rare type of melanoma that occurs mostly on mucosal surfaces. The head and neck region is the most common site for these melanomas. The following cases described herein include patients diagnosed with primary non-cutaneous melanomas. The locations included the parotid gland (one case), the submandibular gland (one case), and the nasal cavity and paranasal sinuses (three cases). Among these patients, one patient developed lymph node metastasis and one patient had distant metastasis. Treatment included endoscopic surgery (one case), endoscopic surgery with adjuvant radiotherapy (one case), open surgery (one case), and palliative chemotherapy (one case). One patient refused to receive treatment. After treatment, one patient had local recurrence. A local and distant recurrence was noted in one case. This report aims to describe clinical features, treatment options, and prognosis of primary non-cutaneous melanomas of the head and neck.

Clinical and histopathological features of lentigo maligna and lentigo maligna melanoma: a retrospective analysis in Korea

Introduction

Lentigo maligna (LM) and lentigo maligna melanoma (LMM) are rare in Asian countries. The histopathological diagnosis of LM is often challenging, and misdiagnosis is common. Although histopathologic features of LM/LMM are known, statistical analysis of them were scarcely reported. In this study, we aimed to investigate the histopathological characteristics of LM/LMM in Korean patients and identify key histopathological clues distinguishing LM from benign lentigo.

Methods

We performed a retrospective study of the clinical and histopathological features of patients diagnosed with LM/LMM at our center between 2011 and 2022. We assessed the histopathological features in each case based on 16 pathological criteria according to previous literature. Pathologically confirmed cases of benign lentigo were analyzed for comparison.

Results

Twenty-one patients (10 with LM and 11 with LMM) were analyzed. Several statistically significant difference existed between the features of LM and benign lentigo (N = 10), including asymmetry of overall structure (p < 0.001), cytologic atypia (p < 0.001), predominant single-cell proliferation (p < 0.001), melanocytic nests (p = 0.033), melanocytes forming rows (p = 0.003), pagetoid spread of melanocytes (p < 0.001), and hair follicle invasion by atypical melanocytes (p < 0.001). Degree of solar elastosis was more severe in group "Age ≥ 60" (p = 0.015), and group "Diameter ≥ 20 mm" (p = 0.043). Presence of elongated rete ridges were less common in the older than 60 age group (p = 0.015) and group "Diameter ≥ 20 mm." Invasion was associated with mitosis (p = 0.001, OR 49.285), multinucleated cells (p = 0.035, OR 17.769), and degree of lymphocyte infiltration (p = 0.004).

Conclusion

This study investigated the clinical and histopathologic characteristics of LM and LMM in Koreans. Although histopathological diagnosis is challenging, especially in the early stages of LM, our data showed essential histopathological changes in architectural, cytological, and dermal patterns. Considering the potential aggressiveness of LM/LMM, it is essential to recognize its histopathological features and provide timely management.

Differentiating between early melanomas and melanocytic nevi: A state-of-the-art review

Clinicians and dermatologists are challenged by accurate diagnosis of melanocytic lesions, due to melanoma's resemblance to benign skin conditions. Several methodologies have been proposed to diagnose melanoma, and to differentiate between a cancerous and a benign skin condition. First, the ABCD rule and Menzies method use skin lesion characteristics to interpret the condition. The 7-point checklist, 3-point checklist, and CASH algorithm are score-based methods. Each of these methods attributes a score point to the features found on the skin lesion. Furthermore, reflectance confocal microscopy (RCM), an integrated clinical and dermoscopic risk scoring system (iDscore), and a deep convoluted neural network (DCNN) also aids in diagnosis. RCM optically sections live tissues to reveal morphological and cellular structures. The skin lesion's clinical parameters determine iDscore's score point system. The DCNN model is based on a detailed learning algorithm. Therefore, we discuss the conventional and new methodologies for the identification of skin diseases. Moreover, our review attempts to provide clinicians with a comprehensible summary of the wide range of techniques that can help differentiate between early melanomas and melanocytic nevi.

Follicular colonization in melanocytic nevi and melanoma: A literature review

The lentiginous spread of melanocytes into the hair follicle can be observed in a number of benign melanocytic neoplasms such as in nevi but also in sun-induced melanocytic hyperplasia and melanoma. The follicular colonization by melanocytes in melanoma is classified into three distinct patterns: primary follicular melanoma, melanoma with folliculotropism, and invasive melanoma arising from melanoma in situ with folliculotropism. The role of follicular colonization in melanoma pathologic staging is still a matter of debate though the description of the latter has been recommended by the International Collaboration on Cancer Reporting. In this review, we will discuss the role of follicular colonization in melanoma and melanocytic nevi as well as the facts and controversies regarding this topic.

Vulvar and Vaginal Melanomas-The Darker Shades of Gynecological Cancers

Melanomas of the skin are poorly circumscribed lesions, very frequently asymptomatic but unfortunately with a continuous growing incidence. In this landscape, one can distinguish melanomas originating in the mucous membranes and located in areas not exposed to the sun, namely the vulvo-vaginal melanomas. By contrast with cutaneous melanomas, the incidence of these types of melanomas is constant, being diagnosed in females in their late sixties. While hairy skin and glabrous skin melanomas of the vulva account for 5% of all cancers located in the vulva, melanomas of the vagina and urethra are particularly rare conditions. The location in areas less accessible to periodic inspection determines their diagnosis in advanced stages, often metastatic. Moreover, despite the large number of drugs newly approved in recent decades for the treatment of cutaneous melanoma, especially in the category of biological drugs, the mortality of vulvo-vaginal melanomas has remained almost constant. This, together with the absence of specific treatment guidelines due to the lack of a sufficient number of cases to conduct randomized clinical trials, makes melanomas with this localization a discouraging diagnosis, associated with a very poor prognosis. Our aim is therefore to draw attention to this oftentimes overlooked entity in order to encourage the community to employ various strategies meant to increase research in this area. By highlighting the main risk factors of vulvar and vaginal melanomas, as well as the clinical manifestations and molecular changes underlying these neoplasms, ideally novel therapeutic schemes will, in time, be brought into effect.

Reproduction of patterns in melanocytic proliferations by agent-based simulation and geometric modeling

Spatio-temporal patterns of melanocytic proliferations observed in vivo are important for diagnosis but the mechanisms that produce them are poorly understood. Here we present an agent-based model for simulating the emergence of the main biologic patterns found in melanocytic proliferations. Our model portrays the extracellular matrix of the dermo-epidermal junction as a two-dimensional manifold and we simulate cellular migration in terms of geometric translations driven by adhesive, repulsive and random forces. Abstracted cellular functions and melanocyte-matrix interactions are modeled as stochastic events. For identification and validation we use visual renderings of simulated cell populations in a horizontal perspective that reproduce growth patterns observed in vivo by sequential dermatoscopy and corresponding vertical views that reproduce the arrangement of melanocytes observed in histopathologic sections. Our results show that a balanced interplay of proliferation and migration produces the typical reticular pattern of nevi, whereas the globular pattern involves additional cellular mechanisms. We further demonstrate that slight variations in the three basic cellular properties proliferation, migration, and adhesion are sufficient to produce a large variety of morphological appearances of nevi. We anticipate our model to be a starting point for the reproduction of more complex scenarios that will help to establish functional connections between abstracted microscopic behavior and macroscopic patterns in all types of melanocytic proliferations including melanoma.

The differential expression of micro-RNAs 21, 200c, 204, 205, and 211 in benign, dysplastic and malignant melanocytic lesions and critical evaluation of their role as diagnostic biomarkers

Overlapping histological features between benign and malignant lesions and a lack of firm diagnostic criteria for malignancy result in high rates of inter-observer variation in the diagnosis of melanocytic lesions. We aimed to investigate the differential expression of five miRNAs (21, 200c, 204, 205, and 211) in benign naevi (n = 42), dysplastic naevi (n = 41), melanoma in situ (n = 42), and melanoma (n = 42) and evaluate their potential as diagnostic biomarkers of melanocytic lesions. Real-time PCR showed differential miRNA expression profiles between benign naevi; dysplastic naevi and melanoma in situ; and invasive melanoma. We applied a random forest machine learning algorithm to classify cases based on their miRNA expression profiles, which resulted in a ROC curve analysis of 0.99 for malignant melanoma and greater than 0.9 for all other groups. This indicates an overall very high accuracy of our panel of miRNAs as a diagnostic biomarker of benign, dysplastic, and malignant melanocytic lesions. However, the impact of variable lesion percentage and spatial expression patterns of miRNAs on these real-time PCR results was also considered. In situ hybridisation confirmed the expression of miRNA 21 and 211 in melanocytes, while demonstrating expression of miRNA 205 only in keratinocytes, thus calling into question its value as a biomarker of melanocytic lesions. In conclusion, we have validated some miRNAs, including miRNA 21 and 211, as potential diagnostic biomarkers of benign, dysplastic, and malignant melanocytic lesions. However, we also highlight the crucial importance of considering tissue morphology and spatial expression patterns when using molecular techniques for the discovery and validation of new biomarkers.

Incorporation of dermoscopy improves inter-observer agreement among dermatopathologists in histologic assessment of melanocytic neoplasms

Histopathologic assessment of melanocytic neoplasms is the current gold standard of diagnosis. However, there are well recognized limitations including inter-observer diagnostic discordance. This study aimed to determine if integrating dermoscopy with histopathology of melanocytic neoplasms impacts diagnosis and improves inter-observer agreement. We conducted a prospective cohort study in a pigmented lesion clinic. Consecutive melanocytic lesions were identified for biopsy based on atypical gross or dermoscopic features. Standardized immunohistochemistry and levels were ordered on each specimen. The cases were randomized. Three dermatopathologists blinded to the clinical impression assessed each lesion. The cases were then re-randomized and re-assessed with addition of gross clinical and dermoscopic images. Inter-rater reliability (IRR) using Fleiss' kappa statistic revealed an increase from 0.447 without to 0.496 with dermoscopy amongst all dermatopathologists. The kappa increased from 0.495 before to 0.511 with dermoscopy in separating high-grade atypia or melanoma from moderate atypia or less. In 16 of 136 cases, at least 2 of 3 dermatopathologists favored a diagnosis of melanoma only after dermoscopy. In total, the consensus grade of atypia changed in 24.3% (33/ 136) of cases thereby representing changes to excisional margins and patient follow up. This study is limited by the cohort size. Dermoscopy significantly impacts diagnosis and improves identification of early melanomas in high risk populations and improves inter-observer agreement.

Melanin bleaching with potassium permanganate for melanocytic lesions diagnosis in veterinary medicine

ABSTRACT The aim of this study was to microscopically re-evaluate the melanocytic lesions diagnoses established by the Animal Pathology Laboratory of the Federal University of Uberlândia, in the state of Minas Gerais, Brazil, over a period of eleven years; in addition, to perform a comparative analysis between the conventional histopathological (CH) method and the use of the melanin bleaching (MB) technique with potassium permanganate, sulfuric acid, and oxalic acid solutions. The results of the MB method presented a disagreement in 24.32% of the diagnosis previously by CH, with low agreement (61.0%) and low Kappa coefficient (0.2267). Melanoma was the most frequent lesion, more frequent in elderly and non-breed female dogs. The most frequent melanoma location was in the cutaneous tissue. The presence or absence of a pagetoid spread in cutaneous samples, distribution of melanin, pattern of cell layout, cell morphology, degree of cellular atypia, and the number of mitoses verified after MB were the most important criteria to confirm the diagnosis of malignancy or benignity of the lesions. Evaluating pathologists considered MB to be essential for the majority of diagnoses and an efficient complementary method for the diagnosis of melanocytic lesions, even in cases with a moderate degree of pigmentation.

Economic Analysis of a Noninvasive Molecular Pathologic Assay for Pigmented Skin Lesions

Importance

A recently described noninvasive gene expression test (the pigmented lesion assay [PLA]) with adhesive patch-based sampling has the potential to rule out melanoma and the need for surgical biopsy of pigmented lesions suggestive of melanoma with a negative predictive value of 99% compared with 83% for the histopathologic standard of care. The cost implications of using this molecular test vs visual assessment followed by biopsy and histopathologic assessment (VAH) have not been evaluated.

Objective

To determine potential cost savings of PLA use vs the VAH pathway.

Design, Setting, and Participants

This health economic analysis performed from a US payer perspective was based on consensus treatment guidelines and fee schedules from the Centers for Medicare & Medicaid Services. Data for model input were derived from routine use of the test in US dermatology practices and literature. Participants included patients with primary cutaneous pigmented lesions suggestive of melanoma. Data were analyzed from February 8 to December 1, 2017.

Main Outcomes and Measures

The primary analysis consisted of the relative reduction in costs of diagnostic surgical procedures for PLA vs VAH management. Additional analyses included stage-related treatment costs associated with delays in diagnosis.

Results

In the cost analysis for this economic model, the relative reduction in surgical procedure costs (biopsy and subsequent excision), assuming $0 for the PLA to facilitate multiple comparison scenarios, was -$395 compared with VAH. The relative reduction in stage-related treatment costs associated with the PLA was -$433 compared with VAH, primarily associated with avoidance of delays due to false-negative diagnoses. Surveillance costs were reduced by -$119 with the PLA. The total cost of fully adjudicating a lesion suggestive of melanoma by VAH was $947. At a mean selling price reference point for PLA of $500, cost savings of $447 (47%) per lesion tested could be realized.

Conclusions and Relevance

The results of this analysis suggest that the PLA reduces cost and may improve the care of patients with primary pigmented skin lesions suggestive of melanoma.

Classification of Melanocytic Lesions in Selected and Whole-Slide Images via Convolutional Neural Networks

Whole-slide images (WSIs) are a rich new source of biomedical imaging data. The use of automated systems to classify and segment WSIs has recently come to forefront of the pathology research community. While digital slides have obvious educational and clinical uses, their most exciting potential lies in the application of quantitative computational tools to automate search tasks, assist in classic diagnostic classification tasks, and improve prognosis and theranostics. An essential step in enabling these advancements is to apply advances in machine learning and artificial intelligence from other fields to previously inaccessible pathology datasets, thereby enabling the application of new technologies to solve persistent diagnostic challenges in pathology. Here, we applied convolutional neural networks to differentiate between two forms of melanocytic lesions (Spitz and conventional). Classification accuracy at the patch level was 99.0%–2% when applied to WSI. Importantly, when the model was trained without careful image curation by a pathologist, the training took significantly longer and had lower overall performance. These results highlight the utility of augmented human intelligence in digital pathology applications, and the critical role pathologists will play in the evolution of computational pathology algorithms.

Pushing and loss of elastic fibers are highly specific for melanoma and rare in melanocytic nevi

The histopathological differentiation of melanocytic nevi from malignant melanoma (MM) is based on well-known criteria, and is straightforward in the vast majority of cases. However, there are few cases of melanocytic lesions (ML), the diagnosis of which is very challenging or even impossible. Here we have studied several morphological characteristics with particular focus on elastic fibers (EF) to identify features, helpful for the distinction between nevi and MM. In a monocentric retrospective study we have analyzed 14 morphological histological characteristics in 30 MMs and 90 nevi, encompassing 30 compound/dermal nevi, 30 junctional nevi, 30 dysplastic nevi. All consecutive cases were retrieved from the archives of our tertiary referral centre during the 6-month study period. Nine characteristics including loss of EF in the ML, loss of EF in lesional fibrosis, pushing of the EF, UV-elastosis, loss of rete ridges of the epidermis, regression of the ML, atrophy of the epidermis, pigment incontinence, and concentric eosinophilic fibroplasia (CEF) showed a statistical significant difference (p < 0.05 and at least an OR > 2) distinguishing nevi from MM. Loss of EF was found in 73.1% of MM cases, but in less than 2.5% of nevi. We identified nine morphological characteristics that are helpful to differentiate melanocytic nevi from MM. A loss of the EF in a ML appeared to be highly associated with MM.

Three-dimensional experiments and individual based simulations show that cell proliferation drives melanoma nest formation in human skin tissue

Background

Melanoma can be diagnosed by identifying nests of cells on the skin surface. Understanding the processes that drive nest formation is important as these processes could be potential targets for new cancer drugs. Cell proliferation and cell migration are two potential mechanisms that could conceivably drive melanoma nest formation. However, it is unclear which one of these two putative mechanisms plays a dominant role in driving nest formation.

Results

We use a suite of three-dimensional (3D) experiments in human skin tissue and a parallel series of 3D individual-based simulations to explore whether cell migration or cell proliferation plays a dominant role in nest formation. In the experiments we measure nest formation in populations of irradiated (non-proliferative) and non-irradiated (proliferative) melanoma cells, cultured together with primary keratinocyte and fibroblast cells on a 3D experimental human skin model. Results show that nest size depends on initial cell number and is driven primarily by cell proliferation rather than cell migration.

Conclusions

Nest size depends on cell number, and is driven primarily by cell proliferation rather than cell migration. All experimental results are consistent with simulation data from a 3D individual based model (IBM) of cell migration and cell proliferation.

Electronic supplementary material

The online version of this article (10.1186/s12918-018-0559-9) contains supplementary material, which is available to authorized users.

A proposed classification for follicular involvement by melanoma

BACKGROUND

Folliculotropism in melanoma is poorly characterized and standard categorization for follicular involvement by melanoma is unavailable. We propose a logical categorization system.

METHODS

We conducted a search of our archives over a 24-year period for cases mentioning the terms follicle, follicular, folliculotropic, folliculocentric and melanoma.

RESULTS

We identified 90 cases of melanoma with involvement of the hair follicle. Distinct patterns were identified. The invasive patterns were primary follicular, folliculotropic and invasive arising from melanoma in situ (MIS) with extensive follicular involvement. Follicular involvement by MIS was either lentiginous, nested or a combination of both. A total of 29 invasive melanomas were identified. Of these 12 had invasive melanoma around the hair follicle, 2 were primary follicular melanomas, 7 showed folliculotropism and 3 were invasive melanomas arising from MIS around the follicle. Seventeen invasive melanomas had follicles only involved by MIS (9 nested, 6 nested and lentiginous and 2 lentiginous). A total of 61 cases of MIS with follicular involvement were identified; of these 33 were lentiginous, 10 nested and 18 both lentiginous and nested.

CONCLUSION

We propose that the three distinct patterns of follicular involvement by invasive melanoma and the three distinct patterns of MIS will be valuable for logically categorizing involvement of the hair follicle by melanoma.

Significance of epidermal mitoses in challenging melanocytic proliferations

BACKGROUND

Accurate diagnosis of melanoma remains histologically challenging. Dermal mitoses support malignancy, but are only occasionally seen in melanomas. As melanomagenesis is thought to begin at the dermal-epidermal junction, we investigated the significance of epidermal melanocytic mitoses (EMM) in a spectrum of lesions with molecular characterization.

METHODS

Epidermal mitoses density (EMD) was evaluated in 46 straightforward lesions (24 benign and 22 malignant) and 30 challenging lesions with expert interpretation, fluorescence in situ hybridization and myPath-score characterization (12 favor-benign, 9 favor-malignant and 9 ambiguous). EMD was correlated with clinicopathologic parameters and myPath.

RESULTS

In straightforward cases, 25% nevi and 77% melanomas had EM. Median EMD was significantly lower in nevi vs. melanomas (0/mm vs. 0.04/mm, p = 0.001). EMD (0.01/mm-cutoff) had 77% sensitivity, 79% specificity discriminating melanomas from nevi. In challenging cases, 17% favor-benign, 67% favor-malignant and 78% ambiguous lesions had EM. EMD (0.01/mm-cutoff) had 67% sensitivity, 82% specificity on 21 non-ambiguous lesions, similar to myPath. EMD was less accurate in Spitzoid lesions, which have high EMD and dermal mitoses.

CONCLUSION

While EMD is not an adequate single criterion in diagnosing melanoma, our results validate its discriminatory potential, suggesting that EM should prompt closer investigation for malignancy. Expanded studies with clinical follow up are warranted to further assess the EM utility in classifying melanocytic lesions.

Giant congenital melanocytic nevi: selected aspects of diagnostics and treatment

Background

Treatment of giant melanocytic nevi (GMN) remains a multidisciplinary challenge. We present analysis of diagnostics, treatment, and follow-up in children with GMN to establish obligatory procedures in these patients.

Material/Methods

In 24 children with GMN, we analyzed: localization, main nevus diameter, satellite nevi, brain MRI, catecholamines concentrations in 24-h urine collection, surgery stages number, and histological examinations. The t test was used to compare catecholamines concentrations in patient subgroups.

Results

Nine children had “bathing trunk” nevus, 7 had main nevus on the back, 6 on head/neck, and 2 on neck/shoulder and neck/thorax. Brain MRI revealed neurocutaneous melanosis (NCM) in 7/24 children (29.2%), symptomatic in 1. Among urine catecholamines levels from 20 patients (33 samples), dopamine concentration was elevated in 28/33, noradrenaline in 15, adrenaline in 11, and vanillylmandelic acid in 4. In 6 NCM children, all catecholamines concentrations were higher than in patients without NCM (statistically insignificant). In all patients, histological examination of excised nevi revealed compound nevus, with neurofibromatic component in 15 and melanoma in 2. They remain without recurrence/metastases at 8- and 3-year-follow-up. There were 4/7 NCM patients with more than 1 follow-up MRI; in 1 a new melanin deposit was found and in 3 there was no progression.

Conclusions

Early excision with histological examination speeds the diagnosis of melanoma. Brain MRI is necessary to confirm/rule-out NCM. High urine dopamine concentration in GMN children, especially with NCM, is an unpublished finding that can indicate patients with more serious neurological disease. Treatment of GMN children should be tailored individually for each case with respect to all medical/psychological aspects.

Histopathological characterization of primary cutaneous melanoma using infrared microimaging: a proof-of-concept study

BACKGROUND

The diagnosis of malignant melanoma is based upon the histological evaluation of the lesion. As such, the morphological interpretation relies on the expertise of a dermatopathologist. Infrared microimaging is emerging as a new powerful tool to investigate tissue biochemistry. Infrared spectra probe the biochemical constitution of the sample and are real tissue-specific spectroscopic fingerprints.

OBJECTIVES

To assess the potential of infrared microimaging to aid in the analysis of tissue sections from primary cutaneous melanomas.

METHODS

Ten samples of melanoma sections from the main histological subtypes were investigated using infrared microimaging combined with multivariate statistical analyses.

RESULTS

This methodology yielded highly contrasted colour-coded images that permitted to highlight tissue architecture without any staining. It was possible to discriminate tumour areas from normal epidermis automatically, and intratumoral heterogeneity as revealed by our approach was correlated with the aggressiveness of the tumour.

CONCLUSIONS

This proof-of-concept study shows that infrared microimaging could help in the diagnosis of primary cutaneous melanoma.

Nevi of Special Sites

Melanocytic nevi can have a wide range of histologic appearances. Within the spectrum of nevi, there exists a group that presents in certain anatomic locations with histologically worrisome features but nonetheless benign behavior. This group of nevi has been broadly categorized as nevi of special sites. The anatomic locations affected by this group include the embryonic milkline (breast, axillae, umbilicus, genitalia), flexural areas, acral surfaces, ear, and scalp. Nevi in these locations may be mistaken for melanomas because of their histologic appearance, resulting in inappropriate overtreatment of patients. In this article, the authors review the histologic features of these special site nevi and discuss the criteria that help distinguish them from melanoma.

Fluorescence in situ hybridization as a tool for microstaging in malignant melanoma

Up to 30-50% of melanomas arise in association with a nevus. Accurately defining, the nevus from the melanoma can significantly affect microstaging. Recently, we showed that a targeted fluorescence in situ hybridization (FISH) assay could distinguish between benign nevi and melanoma with a sensitivity of 87% and specificity of 95%. In this study, we evaluated the potential of this same assay for use in the microstaging of melanoma. We performed FISH on 36 cases of melanoma occurring in association with a nevus and 6 cases of nevoid melanoma with deep dermal involvement. In the melanomas with associated benign nevi, FISH enumeration was performed separately on the histologically malignant and benign components. In the nevoid melanomas, FISH was performed on the deep dermal areas. On the basis of the criteria developed in our earlier studies, we determined the sensitivity of the assay within the malignant areas and the specificity within the benign areas of melanomas with associated nevi. In addition, we evaluated the sensitivity and specificity within a group of six nevoid melanomas with deep dermal involvement. Among melanomas with associated nevi, 28 of 36 cases (78%) tested positively in the histologically malignant areas. The benign nevus components were uniformly negative for all criteria. Six of six nevoid melanomas (100%) tested positively in the deep dermal area. FISH analysis with probes targeting 6p25, 6q23, 11q13 and CEP6 can effectively discriminate the malignant and benign components of melanomas with associated nevi and can be used as an adjunctive tool for microstaging. The assay has high sensitivity for the malignant areas of nevus-associated melanomas and outstanding specificity for the benign areas. The sensitivity is independent of the morphological features, and the assay performs well in nevoid melanoma cases.

The role of surgery in the management of congenital melanocytic naevi in children: a perspective from Great Ormond Street Hospital

Recent advances in research have prompted this review of the role of surgery in the management of congenital melanocytic naevi (CMNs). Good data on the incidence of neurological and malignant complications of CMNs have re-fuelled the debates on whether surgery decreases the risk of malignant melanoma and whether early surgery is advantageous. We conclude the following: 1) untreated CMNs can lighten spontaneously, sometimes dramatically, 2) routine surgery has not been demonstrated to reduce the risk of malignancy and is, therefore, for cosmetic reasons only, 3) early surgery has not been shown to be advantageous and carries increased anaesthetic risk and 4) there is some evidence that surgical intervention may adversely affect the behaviour of the CMN cells. Our current practice is based on the following guidelines: 1) patients are treated in a multidisciplinary-team setting which includes the specialties of paediatric dermatology, plastic surgery and neuroradiology with access to neurology, neurosurgery and oncology, 2) serial photographs are taken at yearly intervals to assess spontaneous lightening. 3) all routine surgery is delayed for at least the first year. 4) patients with facial CMNs (either the principal lesion or large satellites) are offered surgery for cosmetic reasons, 5) patients with a single, easily excisable CMN are offered surgery for cosmetic reasons and 6) all families are made aware of the possibility of spontaneous lightening and the possibility that surgery may have effects on the behaviour of naevus cells.

Sensitivity and specificity of histological criteria in the diagnosis of conventional cutaneous melanoma

The efficacy of the histological criteria currently used in the diagnosis of melanoma is still to be defined. We performed a quantitative analysis of 72 conventional (non-Spitzoid, nondesmoplastic) melanomas and 73 conventional melanocytic naevi, used as controls, for 13 histological diagnostic parameters (dimension >6 mm, asymmetry, poor circumscription, irregular and confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, cytological atypia, mitoses, necrosis and dermal lymphocytic infiltrate). Differences in the distribution of selected parameters between the two groups were investigated by Fisher's exact test; for each parameter sensitivity and specificity were calculated. Results showed that all parameters, except poor circumscription, seemed to be significantly associated with melanoma (P<0.05). Cytological atypia, dermal lymphocytic infiltrate, asymmetry, dimension >6 mm and absence of maturation showed a high sensitivity (>90%); absence of maturation, mitoses, necrosis, asymmetrical melanin, suprabasal melanocytes and melanin in deep cells showed a high specificity (>90%); irregular-confluent nests and single melanocytes predominating were poorly sensitive and poorly specific. In melanomas < or =2 mm, two additional parameters were sensitive (> or =90%): suprabasal melanocytes and single melanocytes predominating. We conclude that not all parameters showed to have the same diagnostic value. Absence of maturation and, limited to melanomas < or =2 mm, suprabasal melanocytes were the most discriminating (sensitive and specific) histological features. Cytological atypia, dimension >6 mm, suprabasal melanocytes and mitoses were additional reliable diagnostic features, showing a relatively high sensitivity and a relatively high specificity. Other useful features were dermal lymphocytic infiltrate and asymmetry (sensitive) and necrosis, asymmetrical melanin and melanin in deep cells (specific).

A Subgroup of Melanocytic Nevi on the Distal Lower Extremity (Ankle) Shares Features of Acral Nevi, Dysplastic Nevi, and Melanoma In Situ

Melanocytic lesions in certain locations (eg, genital, breast, acral) may have histologic and clinical features simulating melanoma. Here we describe a group of lesions from the lower distal extremity and analyze their histologic features and possible relation to dysplastic nevi (DN) and melanomas. One hundred fifteen melanocytic lesions from the ankle were retrieved from January 1990 to August 2006 from the files of M. D. Anderson Cancer Center and were classified as benign melanocytic nevi (BN; n=17), DN (n=35), melanomas (MM; n=52), and melanocytic nevi of the ankle with atypical features (MNAAF; ie, cases that did not readily fit in any of the previous categories, n=11). Data analyzed included clinical (age and sex) and histologic features (circumscription, symmetry, cohesiveness of nests, suprabasal melanocytes, confluence, single-cell proliferation, nuclear chromasia, size, and nucleolar features). Follow-up was collected for all MNAAF. MNAAF differ from the other types of lesions in regard to sex incidence (73% in women). The median age of those patients MNAAF was 47 years (range 29 to 76 y). All MNAAF showed moderate-severe architectural disorder whereas 78% showed only mild-moderate cytologic atypia. No MNAAF cases had recurred after follow-up (4 mo to 13 y). This study highlights a group of melanocytic lesions located on the ankle that share histologic features with acral nevi, DN, and melanoma. These lesions are more predominant in females and have moderate to severe architectural atypia but only mild-moderate cytologic atypia. After complete excision, follow-up data indicate an apparently benign outcome. Pathologists should be aware of this type of lesions to avoid overdiagnosis of melanoma.

Dispelling the myth of the "benign hair sign" for melanoma

The vast majority of melanocytic lesions with hair, such as congenital melanocytic nevi, are benign. However, there is a notion that the presence of one or more hairs in a melanocytic lesion is confirmatory for the benign nature of the lesion. To dispel this notion, we present 3 examples of melanocytic lesions that showed terminal hairs on clinical and dermoscopic evaluation, but in which the final diagnosis was invasive melanoma. Thus, integrating all clinical and dermoscopic findings, rather than relying on a single criterion for the lesion at hand should guide clinicians to the correct diagnosis.

Interobserver reproducibility of histological features in cutaneous malignant melanoma

AIMS

To assess the interobserver reproducibility of certain histological features proposed for the diagnosis of melanoma.

METHODS

In a series of melanomas, 13 histological parameters were analysed: dimension > 6 mm, asymmetry, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis.

RESULTS

The agreement (reproducibility) between the nine observers was excellent (kappa > 0.75) for 10 of the 13 examined features (dimension > 6 mm, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, mitoses, and necrosis). The agreement for asymmetry was very close to excellence (kappa = 0.74), and that for cytological atypia (kappa = 0.65) and dermal lymphocytic infiltrate (kappa = 0.47) was slightly lower, but in the fair to good agreement range. The kappa values obtained by comparison with the majority diagnosis were generally high (> or = 0.85); the mean value of kappa was lower (0.70) for only one parameter (dermal lymphocytic infiltrate).

CONCLUSIONS

The parameters investigated showed an overall good reproducibility.