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.