Search results for "Lentigo Maligna"

Delineation of Malignant Skin Tumors by Hyperspectral Imaging

2018

This chapter outlines a new non-invasive method for delineation of skin lesions such as lentigo maligna and lentigo maligna melanoma. The method is based on the analysis of hyperspectral (HS) images taken in vivo before surgical excision of the lesions. For this, characteristic features of the spectral signatures of diseased pixels and healthy pixels are extracted, which combine the intensities in a few selected wavebands with the coefficients of the wavelet frame transforms of the spectral curves. To reduce dimensionality and to reveal the internal structure of the datasets, the diffusion maps (DM) technique is applied. The averaged Nearest Neighbor and the Classification and Regression Tr…

Classification par méthodes d’apprentissage supervisé et faiblement superviséd’images multimodales pour l’aide au diagnostic du lentigo malin en derm…

2021

Carried out in collaboration with the Saint-Étienne University Hospital, this work provides additional information to help the skin diagnosis by providing new decision methods on Lentigo Maligna and Lentigo Maligna Melanoma pathologies. To this end, the modalities regularly used in clinical conditions are made available to this work and are orchestrated within a multimodal process. Among image modalities, may be mentioned the clinical photography, the dermatoscopy, and the confocal reflectance microscopy. Initially, the first steps of this manuscript focus on reflectance confocal microscopy as the work in computer diagnostic assistance is relatively underdeveloped, in particular on the dete…

Delineating margins of lentigo maligna using a hyperspectral imaging system

2014

Lentigo maligna (LM) is an in situ form of melanoma which can progress into invasive lentigo maligna melanoma (LMM). Variations in the pigmentation and thus visibility of the tumour make assessment of lesion borders challenging. We tested hyperspectral imaging system (HIS) in in vivo preoperative delineation of LM and LMM margins. We compared lesion margins delineated by HIS with those estimated clinically, and confirmed histologically. A total of 14 LMs and 5 LMMs in 19 patients were included. HIS analysis matched the histopathological analysis in 18/19 (94.7%) cases while in 1/19 (5.3%) cases HIS showed lesion extension not confirmed by histopathology (false positives). Compared to clinic…

Identification of progenitor cancer stem cell in lentigo maligna melanoma.

2008

:  The potential role of stem cells in neoplasia has aroused considerable interest over the past few years. A number of known biologic characteristics of melanomas support the theory that they may originate in a mutated stem cell. Melanocytic stem cell markers have been described recently. Moreover, the CD133 cells that show surface markers for CD34 are stem cells primitive. These stem cells are capable of differentiating into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. The identification of cancer stem/initiating cells with a crucial role in tumor formation may open up new pharmacologic perspectives. The purpose of this study is to detect the expression of …

Lentigo Maligna:Un Approccio Concreto

2008

Hyperspectral imaging in detecting dermal invasion in lentigo maligna melanoma

2017

Ablative fractional laser-assisted photodynamic therapy for lentigo maligna: a prospective pilot study.

2019

Background Lentigo maligna (LM) is an in‐situ form of melanoma carrying a risk of progression to invasive lentigo maligna melanoma (LMM). LM poses a clinical challenge, with subclinical extension and high recurrence rates after incomplete surgery. Alternative treatment methods have been investigated with varying results. Photodynamic therapy (PDT) with methylaminolaevulinate (MAL) has already proved promising in this respect. Objectives To investigate the efficacy of ablative fractional laser (AFL)‐assisted PDT with 5‐aminolaevulinic acid nanoemulsion (BF‐200 ALA) for treating LM. Methods In this non‐sponsored, prospective pilot study ten histologically verified LMs were treated with AFL‐as…

Matrix metalloproteinases 2 and 9 in lentigo maligna melanoma

2009

Unsupervised Numerical Characterization in Determining the Borders of Malignant Skin Tumors from Spectral Imagery

2021

For accurate removal of malignant skin tumors, it is crucial to assure the complete removal of the lesions. In the case of certain ill-defined tumors, it is clinically challenging to see the true borders of the tumor. In this paper, we introduce several computationally efficient approaches based on spectral imaging to guide clinicians in delineating tumor borders. First, we present algorithms that can be used effectively with simulated skin reflectance data. By using simulated data, we gain detailed information about the sensitivity of the different approaches and how variables defined by algorithms act in the skin model. Second, we demonstrate the performance of the algorithms with spectra…

Extrafacial Lentigo Maligna: A Report on 14 Cases and a Review of the Literature

2016

Lentigo maligna is the most common form of in situ melanoma. It is most often found on the head and neck, and its clinical and dermoscopic features in this location have been extensively described in the literature. We present a series of 14 patients diagnosed with extrafacial lentigo maligna and lentigo maligna melanoma at Hospital General de Valencia and Hospital de Manacor in Spain, and describe the clinical, dermoscopic, and histologic features observed. Most of the melanomas were located on the upper limbs; the next most common locations were the trunk and the lower limbs. The dermoscopic patterns were consistent with facial lentigo maligna and superficial spreading melanoma. Extrafaci…