Quantitative melanoma diagnosis using spectral phasor analysis of hyperspectral imaging from label-free slices.

Introduction: Melanoma diagnosis traditionally relies on microscopic examination of hematoxylin and eosin (H&E) slides by dermatopathologists to search for specific architectural and cytological features. Unfortunately, no single molecular marker exists to reliably differentiate melanoma from benign lesions such as nevi. This study explored the potential of autofluorescent molecules within tissues to provide molecular fingerprints indicative of degenerated melanocytes in melanoma. Methods: Using hyperspectral imaging (HSI) and spectral phasor analysis, we investigated autofluorescence patterns in melanoma compared to intradermal nevi. Using UV excitation and a commercial spectral confocal microscope, we acquired label-free HSI data from the whole-slice samples. Results: Our findings revealed distinct spectral phasor distributions between melanoma and intradermal nevi, with melanoma displaying a broader phasor phase distribution, signifying a more heterogeneous autofluorescence pattern. Notably, longer wavelengths associated with larger phases correlated with regions identified as melanoma by expert dermatopathologists using H&E staining. Quantitative analysis of phase and modulation histograms within the phasor clusters of five melanomas (with Breslow thicknesses ranging from 0.5 mm to 6 mm) and five intradermal nevi consistently highlighted differences between the two groups. We further demonstrated the potential for the discrimination of several melanocytic lesions using center-of-mass comparisons of phase and modulation variables. Remarkably, modulation versus phase center of mass comparisons revealed strong statistical significance among the groups. Additionally, we identified the molecular endogenous markers responsible for tissue autofluorescence, including collagen, elastin, NADH, FAD, and melanin. In melanoma, autofluorescence is characterized by a higher phase contribution, indicating an increase in FAD and melanin in melanocyte nests. In contrast, NADH, elastin, and collagen dominate the autofluorescence of the nevus. Discussion: This work underscores the potential of autofluorescence and HSI-phasor analysis as valuable tools for quantifying tissue molecular fingerprints, thereby supporting more effective and quantitative melanoma diagnosis.

Fenómeno de Lucio como forma de presentación de enfermedad de Hansen / Lucio's phenomenon as a presentation of Hansen disease / Fenômeno de Lucio como forma de apresentação da hanseníase

Resumen: Introducción: la enfermedad de Hansen es una enfermedad infecciosa crónica, causada por Mycobacterium leprae, que afecta principalmente piel y nervios periféricos. Las reacciones leprosas son eventos agudos que se asocian a un aumento de la morbimortalidad de la enfermedad. Objetivo: presentar el caso clínico de un paciente con fenómeno de Lucio, a través del cual se llegó al diagnóstico de enfermedad de Hansen, y remarcar la importancia de tener presente esta enfermedad, poco frecuente en nuestro país, para su correcto diagnóstico. Discusión: el fenómeno de Lucio es un tipo de reacción leprosa mediada por inmunocomplejos. Se caracteriza clínicamente por máculas o placas eritematovioláceas, de aparición súbita, que evolucionan a úlceras necróticas y curan dejando cicatrices estrelladas atróficas. De no mediar tratamiento, puede ser fatal, debido a sobreinfección y sepsis. Este se basa en el tratamiento específico de la infección, asociado a prednisona y un correcto manejo de las heridas.

Summary: Introduction: Hansen disease is a chronic infectious disease caused by Mycobacterium leprae, which mainly affects the skin and peripheral nerves. Leprosy reactions are acute events associated to an increase in the morbimortality of the disease. Objective: the study aims to present the clinical case of patient with Lucio´s phenomenon, which allowed the diagnosis of Hansen disease, and to emphasize on the importance of having this disease in mind for an appropriate diagnosis, despite it being rather unusual in our country. Discussion: Lucio´s phenomenon is a kind of leprosy reaction mediated by immune complexes. Clinically, it is characterized by the sudden onset of macules or blue hemorrhagic plaques, with a rapid evolution to necrotic ulcers, and it heals leaving star-shaped atrophic scars. If it is not treated, it may be fatal due to superinfection and sepsis. Treatment is based on specific medication for the infection, associated to prednisone and the correct handling of injuries.

Resumo: Introdução: a hanseníase é uma doença infecciosa crônica causada pelo Mycobacterium leprae, que acomete principalmente pele e nervos periféricos. As reações hansênicas são eventos agudos que estão associados ao aumento da morbimortalidade da doença. Objetivo: apresentar o caso de um paciente com fenômeno de Lúcio, por meio do qual se chegou ao diagnóstico de hanseníase, e ressaltar a importância de se ter em mente esta doença, rara em nosso meio, para seu correto diagnóstico. Discussão: o fenômeno de Lúcio é um tipo de reação hansênica mediada por imunocomplexos. Caracteriza-se clinicamente por máculas ou placas eritêmato-violáceas de início súbito que evoluem para úlceras necróticas e cicatrizam, deixando cicatrizes estreladas atróficas. Sem tratamento pode ser fatal, devido a superinfecção e sepse; a terapia está baseada no tratamento específico da infecção, associado à prednisona e no manejo correto da ferida.

Comparación de las tinciones con hematoxilina y eosina versus azul de toluidina en la evaluación de los carcinomas cutáneos durante la cirugía micrográfica de Mohs / Comparative study of toluidine blue and hematoxylin and eosin staining in evaluating skin-carcinoma during Mohs micrographic surgery / Comparação da coloração de hematoxilina e eosina versus azul de toluidina na avaliação de carcinomas cutâneos durante a cirurgia micrográfica de Mohs

Resumen: Introducción: la cirugía micrográfica de Mohs es una técnica quirúrgica especializada para el tratamiento del cáncer de piel no melanoma. La histopatología cumple un rol fundamental, y la elección de la tinción es un punto de controversia. Objetivos: comparar el rendimiento de las tinciones de hematoxilina y eosina (HyE) versus azul de toluidina (AT) durante la cirugía. Método: estudio observacional, descriptivo y transversal a partir de noviembre de 2017 hasta mayo de 2018. Se incluyeron las láminas empleadas durante la cirugía en el período mencionado. Estas fueron analizadas por el cirujano de Mohs, tres residentes y una dermopatóloga. Se valoró el rendimiento de ambas tinciones, teniendo en cuenta las características celulares y los elementos del estroma. Resultados: se estudiaron 23 tumores (16 carcinomas basocelulares y 7 carcinomas espinocelulares). Al observarse al microscopio óptico tanto con la tinción de AT como con HyE no se encontraron diferencias significativas entre ambos grupos en lo global, sólo en algunas características, especialmente con la HyE. Conclusiones: es el primer trabajo en Uruguay que compara la eficacia de las dos tinciones durante la cirugía micrográfica de Mohs. Como conclusión tanto la tinción de HyE como el AT son muy buenas técnicas para el diagnóstico de carcinomas cutáneos.

Abstract: Introduction: Mohs micrographic surgery is a specialized surgical technique used to treat nonmelanoma carcinoma. Histopathology plays a vital role in the diagnosis of this condition, and the choice staining method is controversial. Objective: to compare results in the use of hematoxylin and eosin (H&E) versus Toluidine blue (TB) staining during surgery. Method: observational, descriptive and transversal study conducted from November, 2017 until May, 2018 of the slides used during surgeries in the selected period. Slides were analysed by the Mohs surgeon, 3 residents and a dermopathologist to evaluate the results of both staining methods, in consideration of cell features and stromal elements. Results: 23 tumors were analysed (16 Basal Cell carcinomas and 7 Squamous Cell Carcinoma). Microscopic observation of slides prepared with Toluidine blue and hematoxylin and eosin stains did not show significant global differences between both groups, except in terms of a few characteristics, in particular with hematoxylin and eosin stains. Conclusions: this was the first study in Uruguay to evaluate the effectiveness of both staining methods during Mohs micrographic surgery, and it concluded that both Toluidine blue and hematoxylin and eosin stains are very good techniques in evaluating skin-cancer.

Resumo: Introdução: a cirurgia micrográfica de Mohs é uma técnica cirúrgica especializada para o tratamento do câncer de pele não melanoma. A histopatologia desempenha um papel fundamental, onde a escolha da coloração é um ponto de controvérsia. Objetivos: comparar o desempenho das colorações de hematoxilina e eosina versus azul de toluidina durante a cirurgia. Método: estudo observacional, descritivo e transversal de novembro de 2017 a maio de 2018. Foram incluídas as lâminas utilizadas durante as cirurgias no referido período. Estas foram analisadas pelo cirurgião especializado na técnica de Mohs, 3 residentes e um dermatopatologista onde foi avaliado o desempenho de ambas as colorações, levando em consideração as características celulares e os elementos do estroma. Resultados: foram estudados 23 tumores (16 carcinomas basocelulares e 7 carcinomas espinocelulares). Quando observados ao microscópio de luz para coloração AT e H&E, não foram encontradas diferenças significativas entre os dois grupos em geral, apenas em algumas características, especialmente com o H&E. Conclusões: é o primeiro estudo no Uruguai que compara a eficácia dos 2 corantes durante a cirurgia micrográfica de Mohs. Em conclusão, tanto a coloração com hematoxilina e eosina quanto com azul de toluidina são técnicas muito boas para o diagnóstico de carcinomas de pele.

Melanocytic Nevi of Special Sites.

Melanocytic nevi located on specific regions of the body can demonstrate unusual histopathological features such as asymmetry, irregular nesting patterns, pagetoid spread, cytologic atypia, and rarely, mitotic activity. However, despite these features that may raise concern for malignant melanoma, these lesions follow a benign clinical course and do not require intervention. Also known as nevi of special sites or nevi with site-related atypia, these melanocytic nevi were initially described on acral sites and genitalia. Now, additional anatomical sites with known site-related atypia include the ear, conjunctivae, scalp, breast, flexural skin, legs, and back and shoulder. This continuing medical education article presents a review of the histopathological characteristics of special site nevi based on anatomic location. It is imperative for dermatologists, pathologists, and dermatopathologists to distinguish benign melanocytic nevi with site-related atypia from malignant melanoma to avoid unnecessary surgical intervention or treatment.