Lentigo maligno. Claves en el diagnóstico dermatoscópico

A risk-scoring model for the differential diagnosis of lentigo maligna and other atypical pigmented facial lesions of the face: The facial iDScore

BACKGROUND

Due to progressive ageing of the population, the incidence of facial lentigo maligna (LM) of the face is increasing. Many benign simulators of LM and LMM, known as atypical pigmented facial lesions (aPFLs-pigmented actinic keratosis, solar lentigo, seborrheic keratosis, seborrheic-lichenoid keratosis, atypical nevus) may be found on photodamaged skin. This generates many diagnostic issues and increases the number of biopsies, with a subsequent impact on aesthetic outcome and health insurance costs.

OBJECTIVES

Our aim was to develop a risk-scoring classifier-based algorithm to estimate the probability of an aPFL being malignant. A second aim was to compare its diagnostic accuracy with that of dermoscopists so as to define the advantages of using the model in patient management.

MATERIALS AND METHODS

A total of 154 dermatologists analysed 1111 aPFLs and their management in a teledermatology setting: They performed pattern analysis, gave an intuitive clinical diagnosis and proposed lesion management options (follow-up/reflectance confocal microscopy/biopsy). Each case was composed of a dermoscopic and/or clinical picture plus metadata (histology, age, sex, location, diameter). The risk-scoring classifier was developed and tested on this dataset and then validated on 86 additional aPFLs.

RESULTS

The facial Integrated Dermoscopic Score (iDScore) model consisted of seven dermoscopic variables and three objective parameters (diameter ≥ 8 mm, age ≥ 70 years, male sex); the score ranged from 0 to 16. In the testing set, the facial iDScore-aided diagnosis was more accurate (AUC = 0.79 [IC 95% 0.757-0.843]) than the intuitive diagnosis proposed by dermatologists (average of 43.5%). In the management study, the score model reduced the number of benign lesions sent for biopsies by 41.5% and increased the number of LM/LMM cases sent for reflectance confocal microscopy or biopsy instead of follow-up by 66%.

CONCLUSIONS

The facial iDScore can be proposed as a feasible tool for managing patients with aPFLs.

Pigmented lesion on the face: which is the chance of being melanoma using reflectance confocal microscopy features?

Facial melanoma presents itself as a brownish macula, being difficult to differentiate it from benign pigmented lesions of the face on clinical examination. Reflectance confocal microscopy (RCM) assists in diagnosing facial lesions in which dermoscopy has limitations, allowing to increase the diagnostic accuracy. The study aimed to analyze the RCM features of pigmented isolated lesions of the face for diagnosing melanoma. Also, we sought to establish the chance of a pigmented lesion on the face being a melanoma using RCM criteria. In this retrospective and prospective study, 105 clinical pigmented lesions on the face underwent RCM, and cytoarchitectural features in the epidermis, the dermo-epidermal junction (DEJ), and dermis were described. For statistical analysis, the exact chi-square test was applied to the RCM criteria. The odds ratio was estimated using univariate logistic regression. Finally, we used the multiple logistic regression method for creating a nomogram to predict the chance of a lesion being a melanoma. After univariate and multivariate logistic regression, atypical round nucleated cells within the epidermis, pagetoid spread, and follicular dendritic cells presented as statistically significant features. Then, a complex nomogram was created to give the chance of a pigmented lesion on the face being a melanoma. The presence of these three features resulted in a 98% probability for melanoma. This study allowed to estimate the diagnosis of melanoma on the face, using RCM, practicable and feasible in the daily routine, through the presence of some RCM nomogram criteria.

Very Rare Amelanotic Lentigo Maligna Melanoma with Skull Roof Invasion

BACKGROUND

Lentigo malignant melanoma is a melanoma subtype of chronic sun-damaged skin in elderly Caucasians. Amelanotic variants of lentigo malignant are extremely rare.

CASE PRESENTATION

This is a case report of an 80-year-old male patient who presented with a non-pigmented exophytic tumour of his bald head. After complete surgical excision under the suspicion of squamous cell carcinoma, three-dimensional histologic examination confirmed an amelanotic lentigo malignant melanoma with a tumour thickness of 1.76 mm, resected R0. Five years later he developed the first relapse, the other year a satellite metastasis was surgically removed. One year later, this patient had developed a large relapsing lentigo malignant melanoma with skull roof invasion. There was no evidence of distant metastatic spread. Amelanotic lentigo malignant melanoma is a very rare tumour.

CONCLUSIONS

Serial excision or slow Mohs and Mohs micrographic surgery are the treatments of choice especially in the head and neck area. These tumours may be locally very aggressive as it is shown by skull invasion in the present case.