DermLite II: an innovative portable instrument for dermoscopy without the need of immersion fluids

Differentiating Fordyce Spots from Their Common Simulators Using Ultraviolet-Induced Fluorescence Dermatoscopy-Retrospective Study

Fordyce spots (FS) are heterotopic sebaceous glands affecting mostly oral and genital mucosa, commonly misdiagnosed with sexually transmitted infections. In a single-center retrospective study, we aimed to assess the ultraviolet-induced fluorescencedermatoscopy (UVFD) clues of Fordyce spots and their common clinical simulants: molluscum contagiosum, penile pearly papules, human papillomavirus warts, genital lichen planus, and genital porokeratosis. Analyzed documentation included patients' medical records (1 September-30 October 2022) and photodocumentation, which included clinical images as well as polarized, non-polarized, and UVFD images. Twelve FS patients were included in the study group and fourteen patients in the control group. A novel and seemingly specific UVFD pattern of FS was described: regularly distributed bright dots over yellowish-greenish clods. Even though, in the majority of instances, the diagnosis of FS does not require more than naked eye examination, UVFD is a fast, easy-to-apply, and low-cost modality that can further increase the diagnostic confidence and rule out selected infectious and non-infectious differential diagnoses if added to conventional dermatoscopic diagnosis.

Microvascular imaging of the skin

Despite our understanding that the microvasculature plays a multifaceted role in the development and progression of various conditions, we know little about the extent of this involvement. A need exists for non-invasive, clinically meaningful imaging modalities capable of elucidating microvascular information to aid in our understanding of disease, and to aid in the diagnosis/monitoring of disease for more patient-specific care. In this review article, a number of imaging techniques are summarized that have been utilized to investigate the microvasculature of skin, along with their advantages, disadvantages and future perspectives in preclinical and clinical settings. These techniques include dermoscopy, capillaroscopy, Doppler sonography, laser Doppler flowmetry (LDF) and perfusion imaging, laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), including its Doppler and dynamic variant and the more recently developed OCT angiography (OCTA), photoacoustic imaging, and spatial frequency domain imaging (SFDI). Attention is largely, but not exclusively, placed on optical imaging modalities that use intrinsic optical signals to contrast the microvasculature. We conclude that whilst each imaging modality has been successful in filling a particular niche, there is no one, all-encompassing modality without inherent flaws. Therefore, the future of cutaneous microvascular imaging may lie in utilizing a multi-modal approach that will counter the disadvantages of individual systems to synergistically augment our imaging capabilities.

Vascular structures in dermoscopy

Dermoscopy is an aiding method in the visualization of the epidermis and dermis. It is usually used to diagnose melanocytic lesions. In recent years, dermoscopy has increasingly been used to diagnose non-melanocytic lesions. Certain vascular structures, their patterns of arrangement and additional criteria may demonstrate lesion-specific characteristics. In this review, vascular structures and their arrangements are discussed separately in the light of conflicting views and an overview of recent literature.

How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part II. Nonmelanocytic skin tumors

Nonmelanoma skin cancer refers to a broad class of tumors, including actinic keratosis, basal cell carcinoma, and squamous cell carcinoma, and as a group these are the most frequent cancers occurring in light skinned humans. In contrast to the rarity of amelanotic melanoma, nonmelanoma skin cancer commonly lacks pigmentation. Although these tumors rarely cause death related to metastases, they commonly destroy underlying tissues and should be removed at the earliest possible stage. Dermoscopy improves the clinical diagnosis of nonpigmented skin tumors by allowing the visualization of specific vascular structures that are usually not visible to the naked eye. Dermoscopic vascular patterns of several nonmelanocytic nonpigmented skin tumors, such as sebaceous hyperplasia, seborrheic keratosis, clear cell acanthoma, Bowen disease, or nodular cystic basal cell carcinoma are highly specific, allowing a ready diagnosis in most cases. Others, such as actinic keratosis, pyogenic granuloma, or uncommon adnexal tumors, may be difficult to differentiate even with the aid of dermoscopy. For this reason, general guidelines have been established to assist in making the most appropriate management decision. In the second part of this review of dermoscopic vascular structures of nonpigmented skin tumors, the dermoscopic patterns associated with benign and malignant nonmelanocytic skin tumors and recommendations for the management of these tumors will be discussed.

High-Power, Computer-Controlled, Light-Emitting Diode–Based Light Sources for Fluorescence Imaging and Image-Guided Surgery

Optical imaging requires appropriate light sources. For image-guided surgery, in particular fluorescence-guided surgery, a high fluence rate, a long working distance, computer control, and precise control of wavelength are required. In this article, we describe the development of light-emitting diode (LED)-based light sources that meet these criteria. These light sources are enabled by a compact LED module that includes an integrated linear driver, heat dissipation technology, and real-time temperature monitoring. Measuring only 27 mm wide by 29 mm high and weighing only 14.7 g, each module provides up to 6,500 lx of white (400–650 nm) light and up to 157 mW of filtered fluorescence excitation light while maintaining an operating temperature ≤ 50°C. We also describe software that can be used to design multimodule light housings and an embedded processor that permits computer control and temperature monitoring. With these tools, we constructed a 76-module, sterilizable, three-wavelength surgical light source capable of providing up to 40,000 lx of white light, 4.0 mW/cm2 of 670 nm near-infrared (NIR) fluorescence excitation light, and 14.0 mW/cm2 of 760 nm NIR fluorescence excitation light over a 15 cm diameter field of view. Using this light source, we demonstrated NIR fluorescence–guided surgery in a large-animal model.

Dermoscopy and entomology (entomodermoscopy)

Although dermoscopy has been primarily designed for aiding the in vivo diagnosis of skin tumors, recent advances indicate it is also useful in the diagnosis of common skin infections and infestations. As such, dermoscopy connects the research fields of dermatology and entomology into one field of "entomodermoscopy". In this article we give an overview on the current applications of entomodermoscopy.

Multimodal facial color imaging modality for objective analysis of skin lesions

We introduce a multimodal facial color imaging modality that provides a conventional color image, parallel and cross-polarization color images, and a fluorescent color image. We characterize the imaging modality and describe the image analysis methods for objective evaluation of skin lesions. The parallel and cross-polarization color images are useful for the analysis of skin texture, pigmentation, and vascularity. The polarization image, which is derived from parallel and cross-polarization color images, provides morphological information of superficial skin lesions. The fluorescent color image is useful for the evaluation of skin chromophores excited by UV-A radiation. In order to demonstrate the validity of the new imaging modality in dermatology, sample images were obtained from subjects with various skin disorders and image analysis methods were applied for objective evaluation of those lesions. In conclusion, we are confident that the imaging modality and analysis methods should be useful tools to simultaneously evaluate various skin lesions in dermatology.

New technologies for human cancer imaging

Despite technical advances in many areas of diagnostic radiology, the detection and imaging of human cancer remains poor. A meaningful impact on cancer screening, staging, and treatment is unlikely to occur until the tumor-to-background ratio improves by three to four orders of magnitude (ie, 10(3)- to 10(4)-fold), which in turn will require proportional improvements in sensitivity and contrast agent targeting. This review analyzes the physics and chemistry of cancer imaging and highlights the fundamental principles underlying the detection of malignant cells within a background of normal cells. The use of various contrast agents and radiotracers for cancer imaging is reviewed, as are the current limitations of ultrasound, x-ray imaging, magnetic resonance imaging (MRI), single-photon emission computed tomography, positron emission tomography (PET), and optical imaging. Innovative technologies are emerging that hold great promise for patients, such as positron emission mammography of the breast and spectroscopy-enhanced colonoscopy for cancer screening, hyperpolarization MRI and time-of-flight PET for staging, and ion beam-induced PET scanning and near-infrared fluorescence-guided surgery for cancer treatment. This review explores these emerging technologies and considers their potential impact on clinical care. Finally, those cancers that are currently difficult to image and quantify, such as ovarian cancer and acute leukemia, are discussed.

Dry dermoscopy in clinical treatment of alopecia areata

Although dermoscopy is conventionally utilized with immersion gel for diagnosis of pigmented tumor, we utilized dry dermoscopy, which is dermoscopy without immersion gel, for clinical treatment of alopecia areata (AA). The scalp skin and hair of a 38-year-old Japanese male, and 23-, 22- and 47-year-old Japanese females with AA, whose normal hair color was black, were examined by dry dermoscopy. Exclamation mark hairs, short hairs, fractured hairs and black dots, all characteristic of AA, were detected by dry dermoscopy of the scalp of the 23-year-old female with ophiasis type AA. In the case of the 47-year-old female with round hair loss on the occipital scalp and diffuse hair loss over the fronto-vertical region, dry dermoscopy was useful for diagnosis of AA based on hair characteristic of AA. After she received corticosteroid pulse therapy with 500 mg of i.v. methylprednisolone on 3 successive days, her hair showed apparent regrowth and disappearance of the abnormal hairs characteristic of AA, evidenced by dry dermoscopy 1 month later. In a case of long-lasting AA in the 23-year-old female, we found a follicular plaque-like appearance at the opened hair follicle pores by dry dermoscopy. Histopathologically, the incompletely differentiated remnant hair shaft was packed in the follicular infundibulum. In addition, regrowing vellus hairs, which were difficult to clinically recognize, were detected by dry dermoscopy. Dry dermoscopy is therefore useful for both diagnosis and follow up of AA.