Dermoscopy for early detection of facial lentigo maligna

RECURRENT LENTIGO MALIGNA: CONSERVATIVE CONTINUOUS TREATMENT WITH IMIQUIMOD OR REPEATED SURGERY? A LONG-TERM FOLLOW-UP DERMOSCOPIC CASE STUDY

A case of recurrent lentigo maligna in a 45-year-old woman is presented. The disease relapsed several times following the surgical excision of the lesion. An alternative treatment with imiquimod 5% cream was then used. After 4 years of follow-upfrom the last surgery, this treatment achieved total clearance of the lesion. The problems of lentigo maligna diagnosis and treatment are discussed.

Fluorescence-advanced videodermatoscopy (FAV) for the differential diagnosis of suspicious facial lesions: A single-centre experience with pattern analysis and histopathological correlation

BACKGROUND

Fluorescence-advanced videodermatoscopy (FAV) is a new non-invasive high-resolution skin imaging technique to assess pigmented lesions in conjunction with the clinical examination and dermatoscopy.

OBJECTIVES

This is the first prospective study to identify morphologic descriptors and standardized terminology to examine facial pigmented lesions using FAV. The objectives were to identify FAV indicators, which can assist physicians in diagnosing suspicious flat facial pigmented lesions.

METHODS

Consecutive equivocal pigmented lesions were retrospective analysed. Histopathological examination was performed for all the lesions. The main cytomorphological and cytoarchitectural FAV features were described and correlated with histopathological characteristics.

RESULTS

From January to October 2020, 21 consecutive clinically suspected pigmented lesions in 20 patients were analysed using dermatoscopy and FAV and then surgically excised. Histopathological examination identified lentigo maligna (LM), lentigo maligna melanoma (LMM), solar lentigo (SL), flat seborrheic keratosis (SK) and pigmented actinic keratosis (PAK). Thirteen malignant melanocytic lesions were removed (11 LM, 2 LMM), two were diagnosed as PAK, and the remaining six pigmented lesions were SL-SKs. With FAV, large ovoid pleomorphic and dendritic cells arranged in the intrafollicular disposition, are typical of most malignant melanocytic lesions (12/13, 92.3%). No benign lesions displayed these features. In dermatoscopy, this folliculotropism corresponded to the presence of an annular-granular pattern with slate grey dots that were aggregated asymmetrically around follicular openings.

CONCLUSIONS

FAV features can provide an improved diagnostic approach in the differential diagnosis of flat pigmented facial lesions.

The dermoscopic inverse approach significantly improves the accuracy of human readers for lentigo maligna diagnosis

BACKGROUND

A recently introduced dermoscopic method for the diagnosis of early lentigo maligna (LM) is based on the absence of prevalent patterns of pigmented actinic keratosis and solar lentigo/flat seborrheic keratosis. We term this the inverse approach.

OBJECTIVE

To determine whether training on the inverse approach increases the diagnostic accuracy of readers compared to classic pattern analysis.

METHODS

We used clinical and dermoscopic images of histopathologically diagnosed LMs, pigmented actinic keratoses, and solar lentigo/flat seborrheic keratoses. Participants in a dermoscopy masterclass classified the lesions at baseline and after training on pattern analysis and the inverse approach. We compared their diagnostic performance among the 3 timepoints and to that of a trained convolutional neural network.

RESULTS

The mean sensitivity for LM without training was 51.5%; after training on pattern analysis, it increased to 56.7%; and after learning the inverse approach, it increased to 83.6%. The mean proportions of correct answers at the 3 timepoints were 62.1%, 65.5, and 78.5%. The percentages of readers outperforming the convolutional neural network were 6.4%, 15.4%, and 53.9%, respectively.

LIMITATIONS

The experimental setting and the inclusion of histopathologically diagnosed lesions only.

CONCLUSIONS

The inverse approach, added to the classic pattern analysis, significantly improves the sensitivity of human readers for early LM diagnosis.

Dermatoscopy of flat pigmented facial lesions-evolution of lentigo maligna diagnostic criteria

Recognition of facial lentigo maligna (LM) is often difficult, particularly at early stages. Algorithms and multivariate diagnostic models have recently been elaborated on the attempt to improve the diagnostic accuracy. We conducted a cross-sectional and retrospective study to evaluate dermatoscopic criteria aiding in diagnosis of flat pigmented facial lesions (FPFL). We examined 46 FPFL in 42 Caucasian patients and found that 4 of 20 dermatoscopic criteria reached the significance level required for features indicating malignancy namely, hyperpigmented follicular openings, obliterated follicular opening, annular-granular structures, and pigment rhomboids. Concomitant presence of at least 2 or 3 of the 4 mentioned criteria was significantly more frequent in LM than in pigmented actinic keratosis (PAK). However, despite more frequently seen in LM, these features were also displayed in some of the PAK and other FPFL, so we found them not specific for LM. Although dermatoscopy enhances the diagnostic accuracy in evaluating FPFL, histopathology remains the gold standard for correct diagnosis, making evident the need for improvements in early noninvasive diagnosis of LM.

Lentigo maligna of the face: A quantitative simple method to identify individual patient risk probability on dermoscopy

BACKGROUND/OBJECTIVES

The clinical and dermoscopic differential diagnosis of flat pigmented facial lesions represents a great challenge for the clinicians. Our aim was to report a quantitative method based on dermoscopic features to better classify pigmented facial lesions.

METHODS

This is a retrospective case-series study that analysed the dermoscopic features of 582 pigmented facial lesions.

RESULTS

The individual patient probability of lentigo maligna (LM) was predicted by a multivariate model, with an accuracy of 0.72. According to the odds ratio at the multivariate analysis, an individual scoring index was assigned to each criterion, and a value of 4.56 was identified as optimal cut-off point. Up to a score of 2.5, the probability that a lesion is an LM is 0. The probability increases from 10 to 50% for a score ranging between 4.5 and 6. It is about 90% for a score of 7.

CONCLUSION

The optimal cut-off point obtained and the curve that identifies the probability of a patient having a LM could improve the classification and the management strategies of equivocal pigmented facial lesions.

Dermoscopic and clinical features of head and neck melanoma

BACKGROUND

The dermoscopic criteria of extrafacial melanomas are well-known.

OBJECTIVE

To determine the frequency of dermatoscopic findings in head and neck melanomas (HNM) and to assess the distinguishing dermoscopic criteria of facial and extrafacial melanoma.

METHODS

This observational study included 108 patients with HNM (63% male, mean age 64 years). Participants underwent individual dermoscopic imaging of clinically melanoma. All lesions were excised, and histopathological examination was performed on all specimens.

RESULTS

Drawing on histopathological analysis, lentigo maligna melanoma or lentigo maligna was diagnosed in 60 lesions, superficial spreading melanoma in 18, nodular in 10, desmoplastic in 8, superficial spreading melanoma in situ in 12. The most frequent location for head and neck melanoma was the cheek (60 patients, 55.6%). Eight prominent dermatoscopic features were observed in facial melanoma: annular-granular pattern (18%); rhomboidal structures (29%); pseudonetwork (29%); asymmetrical, pigmented, follicular openings (51%); obliterated hair follicles (8%); red rhomboidal structures (18%); increased density of the vascular network (32%); scar-like depigmentation (59%).

CONCLUSIONS

HNM has specific dermoscopic features, and classical extrafacial dermoscopic rules are less useful for diagnosis of facial melanoma. In our study, further characteristic dermatoscopic findings were detected in facial melanoma such as low frequencies of irregular dots, 2 or fewer colors in lesions, the presence of pseudonetwork, increased density of the vascular network, red rhomboidal structures, in addition to dermatoscopic findings of extrafacial melanoma. Thus, it is concluded that the prediction and identification of HNM may be evident with the help of these signs.

Melanoma in situ: Part I. Epidemiology, screening, and clinical features

The incidence of melanoma has steadily increased over the past 3 decades, with melanoma in situ comprising a disproportionately high percentage of the rising incidence. Our understanding of melanoma in situ has been shaped by epidemiologic and clinical studies. Central to a review of melanoma in situ is a focus on its epidemiology, pathology, biologic behavior, treatment, and clinical outcome, which may differ significantly from that of malignant melanoma. Part I of this continuing medical education article reviews the epidemiology, risk factors, and clinical features of melanoma in situ; part II covers the histopathology, treatment options, and clinical management.

Diagnosis and management of lentigo maligna: a review

Lentigo maligna is a melanocytic neoplasm occurring on sun-exposed skin, usually on the head and neck, of middle-aged and elderly patients. It is thought to represent the in situ phase of lentigo maligna melanoma. The ill-defined nature and potentially large size of lesions can pose significant diagnostic and treatment challenges. The goal of therapy is to cure the lesions in order to prevent development of invasive disease, and surgical excision is the treatment of choice to achieve clear histological margins. Nonsurgical treatment modalities have been reported; however, evidence is lacking to support their use. Age, general health, and comorbidities need to be taken into account when deciding the right treatment modality for each individual patient.

Diagnosis and management of facial pigmented macules

The differential diagnosis of pigmented macules on the mottled chronic sun-damaged skin of the face is challenging and includes lentigo maligna (LM), pigmented actinic (solar) keratosis, solar lentigo, and lichen-planus-like keratosis. Although dermatoscopy improves the diagnostic accuracy of the unaided eye, the accurate diagnosis and management of pigmented facial macules remains one of the most challenging scenarios in daily practice. This is related to the fact that pigmented actinic (solar) keratosis, lichen-planus-like keratosis, and LM may reveal overlapping criteria, making their differential diagnosis clinically difficult. For this reason, practical rules have been introduced, which should help to minimize the risk for inappropriate diagnosis and management of LM.

Clinical usefulness of reflectance confocal microscopy in the management of facial lentigo maligna melanoma

Facial lentigo maligna melanoma can be a diagnostic challenge in daily clinical practice as it has similar clinical and morphological features to other lesions such as solar lentigines and pigmented actinic keratoses. Confocal microscopy is a noninvasive technique that provides real-time images of the epidermis and superficial dermis with cellular-level resolution. We describe 3 cases of suspected facial lentigo maligna that were assessed using dermoscopy and confocal microscopy before histopathology study. In the first case, diagnosed as lentigo maligna melanoma, presurgical mapping by confocal microscopy was performed to define the margins more accurately. In the second and third cases, with a clinical and dermoscopic suspicion of lentigo maligna melanoma, confocal microscopy was used to identify the optimal site for biopsy.

Does it look like melanoma? A pilot study of the effect of sunless tanning on dermoscopy of pigmented skin lesions

BACKGROUND

Dermoscopy has led to an improvement in diagnosing malignant melanoma (MM). Sunless tanning agents containing dihydroxyacetone (DHA) could lead to a decrease in ultraviolet exposure, decreasing the risk of MM. Importantly, DHA has been reported to change dermoscopic features and could thus endanger diagnostic improvement in dermoscopy.

OBJECTIVES

To investigate whether the use of DHA can lead to changes that simulate a real, clinically relevant dermoscopic change, suggesting malignant transformation either in facial solar lentigo/initial seborrhoeic keratosis (SL/ISK) or in naevi on the body.

METHODS

Seven patients with 25 pigmented skin lesions (PSLs) were photographed, resulting in 38 dermoscopic images. Photographs were taken before, 1 week after and 1-2 months after the use of DHA. Two dermatologists separately evaluated the PSLs and their dermoscopic features. For lesions on the body Menzies' method was used, and for facial lesions the criteria defined by Stolz et al. were used.

RESULTS

In facial PSLs equivocal lesions were registered by both evaluators significantly more often after DHA use than before (42% vs. 12%, P=0·021 and 69% vs. 19%, P=0·001). Furthermore, follicular pigmentation that partly mimics that of lentigo maligna was also seen significantly more often after DHA use than before (81% vs. 12%, P<0·001 and 69% vs. 15%, P<0·001) and in these instances the evaluators recommended a biopsy. Equivocal lesions in naevi on the body were not significantly increased after DHA use.

CONCLUSIONS

Dermoscopists that come across unclear dermoscopic findings, especially in facial PSL, should ask patients about the use of DHA.

Dermoscopic features of facial pigmented skin lesions

Four types of facial pigmented skin lesions (FPSLs) constitute diagnostic challenge to dermatologists; early seborrheic keratosis (SK), pigmented actinic keratosis (AK), lentigo maligna (LM), and solar lentigo (SL). A retrospective analysis of dermoscopic images of histopathologically diagnosed clinically-challenging 64 flat FPSLs was conducted to establish the dermoscopic findings corresponding to each of SK, pigmented AK, LM, and SL. Four main dermoscopic features were evaluated: sharp demarcation, pigment pattern, follicular/epidermal pattern, and vascular pattern. In SK, the most specific dermoscopic features are follicular/epidermal pattern (cerebriform pattern; 100% of lesions, milia-like cysts; 50%, and comedo-like openings; 37.50%), and sharp demarcation (54.17%). AK and LM showed a composite characteristic pattern named "strawberry pattern" in 41.18% and 25% of lesions respectively, characterized by a background erythema and red pseudo-network, associated with prominent follicular openings surrounded by a white halo. However, in LM "strawberry pattern" is widely covered by psewdonetwork (87.5%), homogenous structureless pigmentation (75%) and other vascular patterns. In SL, structureless homogenous pigmentation was recognized in all lesions (100%). From the above mentioned data, we developed an algorithm to guide in dermoscopic features of FPSLs.

[Enlarging pigmented facial lesion]

A 75-year-old man presented after recurrence of a pigmented macule on his left cheek. Approximately 8 month before a seborrheic keratosis had been diagnosed clinically and treated with cryosurgery and curettage. Dermatoscopy of the recurrent lesion revealed a number of criteria associated with lentigo maligna including asymmetric pigmented follicular openings, streaks, rhomboidal structures, and homogeneous slate-gray areas. Histopathology confirmed a lentigo maligna melanoma with a Breslow tumor thickness of 0.3 mm.

Dermatoscopy of flat pigmented facial lesions: diagnostic challenge between pigmented actinic keratosis and lentigo maligna

BACKGROUND

The similarity between clinical pictures of pigmented actinic keratosis (PAK) and lentigo maligna (LM) is well known.

OBJECTIVES

To investigate the frequency of dermatoscopic findings suggestive of LM/lentigo maligna melanoma (LMM) in the other facial pigmented skin lesions (FPSL) and to assess the distinguishing dermoscopic criteria of PAK and LM.

METHODS

Eighty-nine FPSL were evaluated with conventional dermatoscopy. The lesions showing one or more dermatoscopic features considered as specific patterns for the diagnosis of LM/LMM, mainly slate-grey to black dots and globules, slate-grey areas, annular-granular pattern, asymmetrical pigmented follicular openings, black blotches, rhomboidal structures, hyperpigmented rim of follicular openings, slate-grey streaks and dark streaks, were included in the study selectively.

RESULTS

PAK was diagnosed in 67, LM or LMM in 20 and lichen planus-like keratosis in two lesions, histopathologically. Eleven essential dermatoscopic features were observed in facial PAK: slate-grey dots (70%); annular-granular pattern (39%); rhomboidal structures (36%); pseudonetwork (36%); black globules (34%); slate-grey globules (33%); black dots (30%); asymmetrical pigmented follicular openings (25%); hyperpigmented rim of follicular openings (21%); slate-grey areas (18%); and streaks (3%).

CONCLUSIONS

PAK has a striking similarity to LM/LMM in clinical and dermatoscopic features, thus representing a diagnostic challange. All dermatoscopic findings except black blotches were observed in PAK. As dermatoscopic diagnosis of a pigmented skin lesion cannot be based on the presence of a single criterion, we may conclude that histopathology still remains the gold standard for correct diagnosis.

[Diagnostic utility of dermoscopy in pigmented actinic keratosis]

The diagnosis of pigmented actinic keratosis can be complicated in clinical practice. The differential diagnosis with lentigo maligna melanoma can be difficult due to common clinical and dermoscopic characteristics. We present 5 cases of pigmented actinic keratosis in 4 patients. The most common dermoscopic finding was a grayish-brown granulation with a perifollicular distribution, present in all lesions, followed by rhomboidal structures in 4 cases, and an annular-granular pattern in 3. In no case were asymmetrical pigmented follicular openings observed. We draw attention to key findings that aid preoperative diagnosis of pigmented actinic keratosis.

The impact of in vivo reflectance confocal microscopy on the diagnostic accuracy of lentigo maligna and equivocal pigmented and nonpigmented macules of the face

Limited studies have reported the in vivo reflectance confocal microscopy (RCM) features of lentigo maligna (LM). A total of 64 RCM features were scored retrospectively and blinded to diagnosis in a consecutive series of RCM sampled, clinically equivocal, macules of the face (n=81 LM, n=203 benign macules (BMs)). In addition to describing RCM diagnostic features for LM (univariate), an algorithm was developed (LM score) to distinguish LM from BM. This comprised two major features each scoring +2 points (nonedged papillae and round large pagetoid cells > 20 microm), and four minor features; three scored +1 point each (three or more atypical cells at the dermoepidermal junction in five 0.5 x 0.5 mm(2) fields, follicular localization of atypical cells, and nucleated cells within the dermal papillae), and one (negative) feature scored -1 point (a broadened honeycomb pattern). A LM score of > or = 2 resulted in a sensitivity of 85% and specificity of 76% for the diagnosis of LM (odds ratio (OR) for LM 18.6; 95% confidence interval: 9.3-37.1). The algorithm was equally effective in the diagnosis of amelanotic lesions and showed good interobserver reproducibility (87%). In a test set of 29 LMs and 44 BMs, the OR for LM was 60.7 (confidence interval: 11.9-309) (93% sensitivity, 82% specificity).

Spreading pigmented actinic keratosis: a review

INTRODUCTION

Spreading pigmented actinic keratosis (SPAK) is a common, but uncommonly reported or appreciated, variant of classic actinic keratosis (AK). It can mimic different pigmented lesions, which may be benign (eg, solar lentigo) or malignant (eg, lentigo maligna).

OBJECTIVE

We sought to review current data and identify areas needing further research to establish diagnostic guidelines for SPAK and to increase awareness of this common entity.

METHODS

A literature search was performed in both PubMed and MEDLINE databases using the search terms "spreading pigmented actinic keratosis," "pigmented solar keratosis," "pigmented actinic," and "pigmented solar." Each article was retrieved, reviewed, and summarized.

RESULTS

SPAK is a rarely reported lesion that can be difficult to distinguish from other benign and malignant pigmented lesions, including seborrheic keratosis, melanoma in situ (lentigo maligna type), and lentigo maligna melanoma. Located mainly on sun-exposed areas and with a size greater than 1.5 cm, the lesion typically spreads laterally. Pathologically, the lesion resembles classic AK with increased basal melanization. The malignancy potential has not yet been elucidated but destructive therapies such as cryotherapy are recommended.

LIMITATIONS

Reports not yet published or not included in the comprehensive databases we used may exist that were not analyzed.

CONCLUSIONS

SPAK can be associated with adjacent melanoma in situ; therefore, its diagnosis merits increased suspicion for coexisting melanoma.

[Skin tumours of the facial area]

Almost the complete spectrum of skin tumours can occur within the facial area, ranging from benign tumours of infancy to typical malignancies of old age. This spectrum is quiet heterogeneous and comprises every cell type within the skin as a possible origin for tumour growth. Among these are cells derived from the epidermis; adnexal structures; connective, fatty, and vascular tissue; muscle; nerves; melanocytes; and skin-infiltrating inflammatory cells. Due to this diversity, a correct assessment of the clinical findings compared with a histopathologic appraisal in cases of uncertainty is mandatory in order to recommend appropriate therapy. The present overview aims to summarise the basics of the most frequent and most important skin tumours occurring on the face.

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.

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.