Understanding the anatomy of dermoscopy of melanocytic skin tumours: Correlation in vivo with line-field optical coherence tomography

BACKGROUND

Early melanoma detection is the main factor affecting prognosis and survival. For that reason, non-invasive technologies have been developed to provide a more accurate diagnosis. Recently, line-field confocal optical coherence tomography (LC-OCT) was developed to provide an in vivo, imaging device, with deep penetration and cellular resolution in three dimensions. Combining the advantages of conventional OCT and reflectance confocal microscopy, this tool seems to be particularly suitable for melanocytic lesions.

OBJECTIVES

The objective of this study was to identify and describe the correlation between specific dermoscopic criteria and LC-OCT features in three dimensions associated with melanocytic lesions.

METHODS

Dermoscopic and LC-OCT images of 126 melanocytic lesions were acquired in three different centres. The following dermoscopic criteria have been considered: reticular pattern, dots and globules, structureless areas, blue-whitish veil, regression structures, negative network, homogeneous pattern, streaks and blotches.

RESULTS

69 (55%) benign and 57 (45%) malignant lesions were analysed. A regular reticular pattern was found associated in the 75% of the cases with the presence of elongated rete ridges with pigmented cells along the basal layer, while atypical reticular pattern showed an irregular organization of rete ridges with melanocytic hyperplasia, broadened and fused ridges and elongated nests. Both typical and atypical dots and globules were found associated with melanocytic nests in the dermis or at the dermoepidermal junction (DEJ), as well as with keratin cysts/pseudocysts. Grey globules corresponded to the presence of melanin-containing dermal inflammatory cells (melanophages) within the papillae. Structureless brown/black areas correlated with alterations of the DEJ. We observed the same DEJ alterations, but with the presence of dermal melanophages, in 36% of the cases of blue/white/grey structureless areas. A description of each LC-OCT/dermoscopy correlation was made.

CONCLUSIONS

LC-OCT permitted for the first time to perform an in vivo, 3D correlation between dermoscopic criteria and pathological-like features of melanocytic lesions.

Line-field confocal optical coherence tomography for actinic keratosis and squamous cell carcinoma: a descriptive study

BACKGROUND

Early and accurate diagnosis of cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) is fundamental to reduce their associated morbidity and to select the correct treatment. Line-field confocal optical coherence tomography (LC-OCT) is a new imaging device that can characterize healthy skin and basal cell carcinoma, but no large studies on keratinocyte cell tumours have yet been published.

AIM

To identify and describe LC-OCT criteria associated with SCC and AK, and to compare LC-OCT findings in these tumours.

METHODS

A retrospective observational multicentre study was conducted. Lesions were imaged with the LC-OCT device before surgery and examined histologically. LC-OCT criteria for AK/SCC were identified and their presence was evaluated in all study lesions. Univariate and multivariate analyses were performed to compare AK and SCCs, and to investigate differences between in situ and invasive tumours.

RESULTS

In total, 158 patients with 50 AK and 108 SCCs (62 in situ and 46 invasive) were included. Cytological and architectural alterations were found in most lesions, and differences were found between AK and SCCs. Although the visualization of the dermoepidermal junction (DEJ) was often hampered by hyperkeratosis and acanthosis, an outlined DEJ without broad strands was observed in almost all AK and almost all in situ SCCs, but in only three invasive SCCs (P < 0.001) when the DEJ was detectable.

CONCLUSION

Our results suggest that LC-OCT can help clinicians in the identification of AK and SCC and their differentiation, providing a real-time and noninvasive examination. Further studies are needed to confirm our data.

FDG PET biomarkers for prediction of survival in metastatic melanoma prior to anti-PD1 immunotherapy

Our aim was to analyse whether biomarkers extracted from baseline ¹⁸F-FDG PET before anti-PD1 treatment contribute to prognostic survival information for early risk stratification in metastatic melanoma. Fifty-six patients, without prior systemic treatment, BRAF wild type, explored using ¹⁸F-FDG PET were included retrospectively. Our primary endpoint was overall survival (OS). Total metabolic tumoral volume (MTV) and forty-one IBSI compliant parameters were extracted from PET. Parameters associated with outcome were evaluated by a cox regression model and when significant helped build a prognostic score. Median follow-up was 22.1 months and 21 patients died. Total MTV and long zone emphasis (LZE) correlated with shorter OS and served to define three risk categories for the prognostic score. For low, intermediate and high risk groups, survival rates were respectively 91.1% (IC 95 80–1), 56.1% (IC 95 37.1–85) and 19% (IC 95 0.06–60.2) and hazard ratios were respectively 0.11 (IC 95 0.025–0.46), P = 0.0028, 1.2 (IC 95 0.48–2.8), P = 0.74 and 5.9 (IC 95 2.5–14), P < 0.0001. To conclude, a prognostic score based on total MTV and LZE separated metastatic melanoma patients in 3 categories with dramatically different outcomes. Innovative therapies should be tested in the group with the lowest prognosis score for future clinical trials.

Super-high magnification dermoscopy can aid the differential diagnosis between melanoma and atypical naevi

BACKGROUND

Dermoscopy is the most widely used noninvasive imaging technique for the clinical diagnosis of melanoma (MM). Super-high (× 400) magnification dermoscopy (D400) has recently been developed; compared with traditional dermoscopy, it can reveal additional features, down to the identification of single melanocytes in the skin.

OBJECTIVES

To evaluate which structures are visible at D400 and to compare them in atypical naevi and MMs.

METHODS

A prospective observational multicentre study was conducted. We enrolled patients who were identified as having atypical melanocytic skin lesions by clinical and/or × 20 magnification dermoscopy (D20) examination, and who were assigned to either excision or follow-up. Lesions were imaged by videodermoscopy at D20 and D400. The presence of pigmented cells and their features were assessed at D400.

RESULTS

In total, there were 79 patients with 57 naevi and 31 MMs. Of the total 88 lesions, 63 (71.6%) were given a histological diagnosis, while the others were followed up for ≥ 12 months, during which they showed no change and were all diagnosed as naevi. Pigmented cells were identified in > 90% of the lesions at D400. Compared with naevi, MMs had a higher frequency of scattered, large, irregular (in shape and size), dendritic/roundish, violet/blue pigmented cells under D400 (P < 0.001). Moreover, dots (P < 0.01), out-of-focus blue structureless areas (P < 0.01) and vessels (P < 0.001) were also more frequent in MMs than in naevi at D400.

CONCLUSIONS

This study showed that D400 can reveal many elements not otherwise visible in traditional D20 dermoscopy, such as pigmented cells and their morphology, which could be useful for the diagnosis of MM.

Line-field confocal optical coherence tomography of basal cell carcinoma: a descriptive study

BACKGROUND

Early diagnosis and subtype classification of basal cell carcinoma (BCC) are crucial to reduce morbidity and optimize treatment. Good accuracy in differentiating BCC from clinical imitators has been achieved with existing diagnostic strategies but lower performance in discriminating BCC subtypes. Line-field confocal optical coherence tomography (LC-OCT) is a new technology able to combine the technical advantages of reflectance confocal microscopy and OCT.

OBJECTIVES

To identify and describe LC-OCT criteria associated with BCC and explore their association with BCC subtypes.

METHODS

Basal cell carcinoma were imaged with a handheld LC-OCT device before surgical excision. LC-OCT images were retrospectively evaluated by three observers for presence/absence of criteria for BCC. Multivariate logistic regression models were used to find independent predictors of BCC subtypes.

RESULTS

Eighty-nine histopathologically proven BCCs were included, of which 66 (74.2%) were pure subtypes [superficial BCC (sBCC): 19/66 (28.8%); nodular BCC (nBCC): 31/66 (47.0%); infiltrative BCC (iBCC): 16/66 (24.2%)]. Lobules, blood vessels and small bright cells within epidermis/lobules were the most frequent criteria for BCC. LC-OCT criteria independently associated with sBCC were presence of hemispheric lobules, absence of lobule separation from the epidermis, absence of stretching of the stroma; with nBCC were presence of macrolobules, absence of lobule connection to the epidermis; and with iBCC were presence of branched lobules.

CONCLUSIONS

This was the first study describing the characteristics of BCC under LC-OCT examination. We proposed morphologic criteria, which could be potentially useful for diagnosis and subtype classification of BCC, as well as for its therapeutic management. Future studies are needed to assess these hypotheses.

The impact of anatomical location and sun exposure on the dermoscopic recognition of atypical nevi and early melanomas: usefulness of an integrated clinical-dermoscopic method (iDScore)

BACKGROUND

The anatomical location of atypical melanocytic skin lesion (aMSL) was never combined into an algorithm for discriminating early melanomas (EM) from atypical nevi (AN).

AIMS

To investigate the impact of body location on the intuitive diagnosis performed in teledermoscopy by dermatologists of different skill levels. A further aim was to evaluate how the integration of the body location could improve an algorithm-aided diagnosis.

METHODS

We retrospectively collected 980 standardized dermoscopic images of aMSL cases (663 AN, 317 EM): data on the anatomical location were collected according to 15 body sites classified into 4 macro-areas of chronically/frequently/seldom/rarely exposure. Through a teledermatology web platform, 111 variously skilled dermoscopists performed either the intuitive diagnosis and 3 algorithm-assisted diagnostic tests (i.e. iDScore, 7-point checklist, ABCD rule) on each case, for a total of 3330 examinations.

RESULTS

In the rarely photoexposed area (side, bottom, abdomen), AN were the most tricky (i.e. highest quote of false positives), due to a frequent recognition of dermoscopic features usually considered as suggestive for melanoma in these lesions; the EM at these sites received the highest quote of false negatives, being generally interpreted as 'featureless' according to these traditional parameters, that were more frequently displayed on the chronically photoexposed area. In rarely and seldom photoexposed area, intuitive diagnosis fails to achieve adequate accuracy for all aMSLs, as the ABCD rule and the 7-point checklist; by applying the iDScore algorithm the diagnostic performance was increased by 15% in young and 17% in experts.

CONCLUSIONS

The body location of an aMSL can affect the quality of intuitive dermoscopic diagnosis, especially in sun-protected areas. Accuracy can be improved by using the iDScore algorithm that assigns a different partial score of each body site.

Structural skin changes in elderly people investigated by reflectance confocal microscopy

BACKGROUND

Reflectance confocal microscopy (RCM) is particularly suitable for the study of skin ageing because it provides nearly histological information in vivo and non-invasively. However, there are no studies that evaluated RCM skin features of a large population older than 70 years.

OBJECTIVES

The aim of our investigation was to study age-related skin changes in an elderly population by RCM and to evaluate their topographical and gender differences.

METHODS

We obtained RCM images of photoprotected (volar arm) and chronic (face) and intermittently photoexposed (dorsal forearm) body sites of 209 volunteers (105 women and 104 men, mean age: 77.5, range 74-81 years). 15 previously reported and new RCM parameters related to skin ageing were assessed.

RESULTS

Photoexposed sites had thicker suprapapillary epidermis, more linear, distant and thin furrows, higher presence of mottled pigmentation, polycyclic papillae and coarse and huddled collagen and lower presence of dermal papillae than the photoprotected site. Irregular honeycomb pattern was not higher in photoexposed sites, indicating that it is probably more dependent on intrinsic ageing. Two ageing scores defined for facial skin ageing (epidermal disarray score and epidermal hyperplasia score) were found useful for the identification of photoageing. Gender differences only concerned some RCM parameters (i.e. thickness of different layers of the epidermis, furrows and collagen score) and some body sites, in line with the fact that women and men of our cohort had no major differences in clinically visible skin ageing.

CONCLUSIONS

Our study confirmed that RCM is a powerful non-invasive technique to microscopically quantify ageing signs and our observations contribute to highlight the differences between intrinsic and extrinsic ageing.

Morphological classification of melanoma metastasis with reflectance confocal microscopy

BACKGROUND

Cutaneous malignant melanoma metastases differential diagnosis is challenging, as clinical and dermoscopic features can simulate primary melanoma or other benign or malignant skin neoplasms, and in-vivo reflectance confocal microscopy could assist. Our aim was to identify specific reflectance confocal microscopy features for cutaneous malignant melanoma metastases, and epidermal and dermal involvement.

METHODS

A retrospective, multicentre observational study of lesions with proven cutaneous malignant melanoma metastases diagnosis between January 2005 and December 2016. Lesions were retrospectively assessed according to morphological features observed at reflectance confocal microscopy. Potential homogeneous subgroups of epidermal or dermal involvement were investigated with cluster analysis.

RESULTS

Cutaneous malignant melanoma metastases (51 lesions in 29 patients) exhibited different frequencies of features according to metastasis dermoscopy patterns. Lesions classified at dermoscopy with nevus-like globular and non-globular patterns were more likely to be epidermotropic, showing characteristics of epidermal and dermal involvement at reflectance confocal microscopy. Other dermoscopy pattern classifications were more likely to be dermotropic, showing characteristics od dermal involvement at reflectance confocal microscopy. Distinguishing features at reflectance confocal microscopy included irregular (78%) and altered (63%) epidermis, pagetoid infiltration (51%), disarranged junctional architecture (63%), non-edged papillae (76%), dense and sparse, and cerebriform nests in the upper dermis (74%), and vascularity (51%). Cluster analysis identified three groups, which were retrospectively correlated with histopathological diagnoses of dermotropic and epidermotropic diagnoses (P < 0.001). The third cluster represents lesions with deep dermis morphological changes, which were too deep for evaluation with reflectance confocal microscopy.

CONCLUSIONS

Specific reflectance confocal microscopy features of cutaneous malignant melanoma metastases for correct diagnosis, and subtype diagnosis, seem achievable in most cases where morphological alterations are located above the deep dermis.

Evaluation of large clinically atypical vulvar pigmentation with RCM: atypical melanosis or early melanoma?

BACKGROUND

Vulvar melanosis can occasionally be clinically challenging by mimicking an early melanoma.

OBJECTIVE

To report our experience of initial evaluation and follow-up in this peculiar subset of vulvar melanosis using reflectance confocal microscopy (RCM).

METHODS

We retrospectively evaluated 18 consecutive cases referred for atypical vulvar pigmentation or for which melanoma was considered and that underwent both RCM examination and histopathological assessment. In 13 cases with available dermoscopic pictures, RCM classification was compared to dermoscopic diagnosis, and in all cases, the density of melanocytes was evaluated on biopsies using MelanA immunostaining.

RESULTS

Among the 18 atypical pigmented lesions, 17 vulvar melanosis and one melanoma were histologically determined. RCM concluded a benign vulvar melanosis in 10 of 17 cases, whereas dermoscopy did so in three of 12 cases. RCM identified the only early malignant lentiginous melanoma. In several cases of vulvar melanosis, RCM could identify foci of melanocytic hyperplasia in an otherwise benign pattern.

CONCLUSIONS

In this clinically and dermoscopically challenging subset of vulvar pigmentations, RCM appears relevant for initial extensive evaluation, especially to target initial biopsy sampling, and to perform non-invasive monitoring of foci of melanocytic hyperplasia.

New findings in non-invasive imaging of cutaneous endometriosis: Dermoscopy, high-frequency ultrasound and reflectance confocal microscopy

BACKGROUND

Cutaneous endometriosis (CE) is rare and its dermoscopic features were reported only in 3 patients. The aim of this study was to examine a case of pigmented CE with multiple non-invasive imaging techniques, to compare the obtained images with histopathology and to define their utility in an early diagnosis of the disease.

CASE REPORT

We performed dermoscopy, high-frequency ultrasound (HFUS), in vivo and ex vivo reflectance confocal microscopy (RCM) of a pigmented CE arising on the caesarean scar of a phototype IV patient, along with histologic studies. Dermoscopy showed a greyish background and a brownish pigmentation. HFUS shows well-demarcated anechoic areas corresponding to ectopic endometrial tissue at histopathologic examination. RCM and OCT only showed the alterations of the epidermis.

CONCLUSION

High-frequency ultrasound could represent a very useful tool for an early diagnosis of CE and its usefulness could be tested in patients with unusual cyclical pain, even before skin lesion appearance. RCM allowed the visualization of skin surface modification due to underlying endometriosic tissue. Dermoscopy showed a new aspect that was probably related to the mix of blood extravasation (ie, greyish background) and epidermal pigmentation (ie, brown pigmentation).

Benign and malignant collision tumors of melanocytic skin lesions with hemangioma: Dermoscopic and reflectance confocal microscopy features

BACKGROUND

Though the combination/collision of nevi or lentigo simplex and hemangiomas is frequent, the malignant collision tumor melanoma-hemangioma is exceptional and can sometime clinically simulate a benign collision. To date, a series of collision tumors of hemangiomas associated with either benign or malignant melanocytic skin lesions (MSL) has yet to be studied by non-invasive imaging and clinico-pathologic correlates.

METHODS

We present 10 cases of patients with collision tumors of hemangioma with different MSL including: 2 in situ lentigo-maligna melanoma, 1 invasive melanoma, 5 melanocytic nevi, and 2 lentigo simplex. The clinical aspect along with the dermoscopic and reflectance confocal microscopy (RCM) features is described and compared with histopathologic findings.

RESULTS

Dermoscopic examination allows to recognize a dark ring in malignant collision melanoma-hemangioma and a jelly ring sign in benign collision of nevi/lentigo simplex-hemangioma. These peculiar features were confirmed by RCM and histopathologic findings.

CONCLUSION

Two simple dermoscopic clues confirmed by RCM features can be proposed to help distinguish between benign and malignant collisions tumors.

Reflectance confocal microscopy identification of subclinical basal cell carcinomas during and after vismodegib treatment

BACKGROUND

Recently, it has been shown that reflectance confocal microscopy (RCM) could identify subclinical basal cell carcinoma (BCC) during vismodegib treatment of locally advanced BCC.

OBJECTIVES

To evaluate specificity and sensitivity of clinical, dermoscopic and RCM examination for BCC in patients with multiple BCCs treated by vismodegib.

METHODS

Ninety four BCCs had 710 clinical, dermoscopic and RCM examinations during 72 weeks of vismodegib treatment. Thirty-eight were biopsied at the end of the treatment. Sensitivity and specificity for these 38 lesions were calculated. BCC diagnoses of clinical, dermoscopic and RCM examination on all the 710 investigations were compared using chi-square test.

RESULTS

Reflectance confocal microscopy was extremely more sensitive than dermoscopy and clinical examination and slightly less specific (sensitivity of 95%, 35% and 33% and specificity of 81%, 88% and 86% for RCM, dermoscopy and clinical examination, respectively) for the identification of residual BCC in the 38 biopsied cases. Considering all the 710 observations, RCM correctly diagnosed more BCCs than dermoscopy and clinical examination.

CONCLUSION

Reflectance confocal microscopy is a non-invasive technique that can detect subclinical residual BCC during and after vismodegib treatment helping the clinician to identify incomplete tumour regression.

Prediction of a nail polish colour applied on a nail

OBJECTIVE

The colour of a nail polish varies according to the nail on which it is applied. The objective of this study was to predict the colour of the nail polish on a given nail and to study how the colour varies depending on the nail polish thickness.

METHODS

Six nail polishes were applied in one, two and three layers on the nails of one subject, thus forming eighteen samples. The spectral reflectances of the eighteen nail polishes applied on the nails with different thicknesses were obtained by spectrophotometry. The spectral reflectances of the nails without polish were also measured using the same technique. The thicknesses of nail polishes were measured by high-definition optical coherence tomography (HD-OCT). Then, to determine the physical parameters of the nail polish itself, we applied the six nail polishes on an opacity drawdown chart and we measured the spectral reflectance and the thickness of each patch using spectrophotometry and HD-OCT, respectively. The Kubelka-Munk theory was used to get the predicted spectral reflectance of the nail polish applied on the nail according to the polish thickness by knowing the parameter of the polish itself and the spectral reflectance of the nail. The predicted spectral reflectances were finally compared with those measured directly on the nails.

RESULTS

The predicted spectral reflectances were rather close to measured ones. Consequently, knowing the colour of the nail without polish and the optical parameters of the nail polish itself, we can estimate the colour of the nail polish applied on the nail depending on its thickness.

CONCLUSION

Our study showed that the Kubelka-Munk theory can be used to predict the nail polish colour. The ability to predict the real colour of a nail polish applied on a nail could help a nail polish manufacturer to improve his polish formulae in order to obtain a precise colour.

Mucosal melanoma: clinical, histological and c-kit gene mutational profile of 86 French cases

BACKGROUND

Mucosal melanomas are rare and highly aggressive tumours. Few studies evaluated mucosal melanomas of locations other than the head and neck region, and other than those of the Asian population.

OBJECTIVES

The objective of this study was to analyse the clinical and histological features, as well as the mutational status of c-kit and b-raf gene of mucosal melanoma in any localization in a French series.

METHODS

We investigated clinical (sex, age, performance status, survival, treatment of the patients and lack of pigmentation of the tumours) and histopathological features (ulceration, Breslow's index, mitotic rate), as well as the mutational status of c-kit and b-raf of 86 mucosal melanomas diagnosed in 15 years in four French University Hospitals.

RESULTS

Most melanomas affected women (72%) and the genital region (46.5%). A fifth of melanomas were amelanotic. 81% of melanomas had a Breslow's index ≥1, whereas all glans melanomas, and most vulvar melanomas had a Breslow index ≤1 mm. Overall survival was 54% at 3 years; 11.6% of the 43 tested mucosal melanomas were c-kit-mutated while the 15 tested genital melanomas were not. The c-kit gene mutation did not influence the overall survival. Age ≥ 50, amelanotic type and performance status ≥1 were not poor prognostic factors in our series.

CONCLUSION

This study confirmed that mucosal melanomas are rare and could be difficult to diagnose being often amelanotic and in hidden sites. Most melanomas were thick at the diagnosis, but glans and vulvar melanomas were thinner probably because of their greater visibility. The frequency of the c-kit mutation varied depending on the initial tumour site. In our series, the prognosis was poor, independently from c-kit mutations and the patient's general health and age. The presence of metastasis at diagnosis was associated with a worse prognosis indicating the importance of an early diagnosis.

[The role of reflectance confocal microscopy in the diagnosis of secondary syphilis of the vulva and anus: A first case report]

PATIENTS AND METHODS

Herein we report the case of an 18-year-old pregnant patient presenting with plantar and ano-genital lesions of syphilis, pharyngitis, erythematosus and scalynasolabial intertrigo and angular cheilitis.

REFLECTANCE CONFOCAL MICROSCOPY

In vivo reflectance confocal microscopy examination (Vivascope 3000^®; Caliber Inc, Rochester, NY, USA, distributed in France by Mavig, Munich) of ano-genital lesions enabled us to identify hyper-reflective elongated rods in the papillary dermis suggesting spirochetes. The diagnosis was confirmed by TPHA and VDRL as well as immunohistological examination.

COMMENTS

We identified for the first time rod shaped structures in ano-genital lesions of secondary syphilis, regularly alternating hyper-reflective and non-reflective areas corresponding to helix-shaped treponemes visualized by darkfield microscopy, which may not be confused with other cell structures.

New-onset vitiligo and progression of pre-existing vitiligo during treatment with biological agents in chronic inflammatory diseases

BACKGROUND

The development of vitiligo during treatment with biological agents is an unusual event and only a few isolated cases have been reported.

OBJECTIVES

To describe the clinical characteristics and evolution of patients developing new-onset vitiligo following initiation of a biological agent for chronic inflammatory disease; and also to report the clinical course of pre-existing vitiligo under biological therapy.

METHODS

This nationwide multicentre, retrospective study, carried out between July 2013 and January 2015, describes the characteristics of a large series of 18 patients (psoriasis N = 8, inflammatory rheumatic diseases N = 8, ulcerative colitis N = 1, uveitis N = 1) who developed new-onset vitiligo while receiving a biological agent.

RESULTS

TNFα inhibitors were the most common biological agent involved (13/18) while anti-IL-12/23 and anti-IL-17 agents or abatacept were less common (4/18 and 1/18 respectively). Mean duration of biological agent exposure before vitiligo onset was 13.9 ± 16.5 months. Outcome was favourable for most patients (15/17) while maintaining the biological agent. Data were also collected for 18 patients (psoriasis N = 5, inflammatory rheumatic diseases N = 10, inflammatory bowel diseases N = 2, SAPHO N = 1) who had pre-existing vitiligo when treatment with a biological agent started (TNFα inhibitors N = 15, ustekinumab N = 1, rituximab N = 1, tocilizumab N = 1). Vitiligo progressed in seven patients and was stable or improved in eight cases.

CONCLUSION

Vitiligo may thus emerge and/or progress during treatment with various biological agents, mainly TNFα inhibitors and could be a new paradoxical skin reaction. De novo vitiligo displays a favourable outcome when maintaining the biological agent, whereas the prognosis seems worse in cases of pre-existing vitiligo.

Reflectance confocal microscopy of mucosal pigmented macules: a review of 56 cases including 10 macular melanomas

BACKGROUND

Although most mucosal pigmented macules are benign, it can be clinically challenging to rule out an early melanoma. Reflectance confocal microscopy (RCM) is a noninvasive imaging technique useful in discriminating between benign and malignant skin lesions.

OBJECTIVES

To describe the confocal aspects of benign and malignant mucosal pigmented macules with histopathological correlations.

METHODS

We retrospectively reviewed the confocal images of 56 labial or genital pigmented macules including 10 macular melanomas. According to the retrospective nature of the study, we evaluated the recorded images chosen by the physicians that performed the RCM examination for each case.

RESULTS

In benign macules, the most frequently observed pattern was a ringed pattern characterized by round or polycyclic papillae, with a hyper-reflective basal layer; another pattern was characterized by sparse bright dendritic cells in the basal layer, the basal epithelial cells being otherwise less reflective. Roundish cells, a high density of dendritic cells with atypias and intraepithelial bright cells were clues to the presence of malignancy.

CONCLUSIONS

Reflectance confocal microscopy seems to be a valuable tool to noninvasively differentiate benign from malignant mucosal pigmented macules and target biopsies in cases of equivocal features.

Reflectance confocal microscopy for mucosal diseases

Non-invasive, real-time microscopic imaging using in vivo reflectance confocal microscopy (RCM) has been demonstrated to be a useful tool for the evaluation of skin diseases and in particular for skin neoplasms. Recently, the RCM devices dedicated to the skin have also been applied to perform "virtual biopsies" of the oral, genital and ocular mucosa. In fact, mucosa is a sensitive area where non invasive imaging techniques are of high interest in order to spare biopsies and excisions. Mucosa is particularly suitable for RCM because of its thin or absent cornified layer and its thin epithelium that allows a deeper penetration of the laser with the consequent possibility of exploring deeper tissue levels. Besides, being useful for the diagnosis, RCM may be helpful to identify the area to be biopsied in case of large or multifocal lesions and may be regarded as a complementary technique for non invasive assessment of treatment efficacy. The RCM features of healthy mucosa are described and a revision of the literature of the mucosal diseases that can be diagnosed by RCM has been performed.

Reflectance confocal microscopy in infectious diseases

In vivo reflectance confocal microscope (RCM) is a high-resolution non-invasive imaging technique that was initially focused on the diagnosis of skin cancers. A rising number of other indications have been later described for the diagnosis and management of inflammatory and infectious dermatological disorders. RCM can identify cutaneous parasites that are not visible to naked eye such as Sarcoptes scabiei and Demodex folliculorum and it allows to better identify the different body parts of bigger parasites such as ticks. Fungal filaments can also be identified as elongated bright structures in the cutaneous upper layers. RCM cannot observe virus directly. However, the cytopathic effect associated with some virus can be recognized. In addition of being helpful for the diagnosis and follow-up after treatment, thanks to its non-invasiveness, RCM allows pathophysiological studies.

Reflectance confocal microscopy features of acral lentiginous melanoma: a comparative study with acral nevi

BACKGROUND

Acral lentiginous melanoma (ALM) can be difficult to differentiate from acral nevus. Reflectance confocal microscopy (RCM) is widely used for the diagnosis of melanocytic tumours, but the RCM features of ALM and acral nevus have not been described yet.

OBJECTIVE

To determine the RCM features of ALM and acral nevus, and their correlation with clinical and histological characteristics.

METHODS

Retrospective study of 17 cases of ALM and 26 acral nevi.

RESULTS

Pagetoid cells were present in all ALMs with a visible epidermis and in three nevi. A proliferation of atypical melanocytes at the dermal-epidermal junction (DEJ) and/or in the dermis was visible in nine ALMs but not in nevi. The histopathological examination of initial skin biopsies was unable to diagnose ALM in four cases, differing from RCM that could identify malignant tumour cells by exploring the whole lesions.

CONCLUSION

Reflectance confocal microscopy can help in the differentiation of ALM and acral nevus, and to guide the biopsy.

In vivo confocal microscopic substrate of grey colour in melanosis

BACKGROUND

Melanosis is the most common cause of mucosal pigmentation and can be clinically difficult to differentiate from early melanoma (MM). Dermoscopy can help in the distinction between melanosis and MM, but in some instances, melanoses may exhibit overlapping features with MM such as the presence of grey colour.

OBJECTIVE

We sought to evaluate whether reflectance confocal microscopy (RCM) can help to better understand the dermoscopic features of melanoses in order to assist clinicians in their diagnosis.

METHODS

All melanoses diagnosed between June 2011 and December 2014 in the Departments of Dermatology of the University of Saint-Etienne (France) and of Modena and Reggio Emilia (Italy), for which dermoscopic and RCM images were available, were included. Twenty-two lesions were biopsied to confirm the clinical diagnosis, whereas the others did not present any change at a follow-up of at least 6 months. The correlation between dermoscopic and RCM features were evaluated by the Spearman's rho correlation coefficient.

RESULTS

55 melanoses were studied: 31 of the oral mucosa and 24 of the genital mucosa. 49% (n = 27) of melanoses exhibited a grey colour under dermoscopy. The grey colour correlated with the presence of melanophages under RCM (ρ = 0.424, P = 0.002).

CONCLUSION

Our findings highlight that the presence of the grey colour on dermoscopy, considered as an alerting feature, is common in melanoses and it is related to the presence of melanin-laden inflammatory cells in the papillary dermis on RCM. When it is present as a 'pure' feature not associated to other colours than brown or to atypical dermoscopical structures, it could be related to the diagnosis of melanosis.