Imaging of intradermal tattoos by optical coherence tomography

BACKGROUND/PURPOSE: Tattoos have become increasingly popular followed by a growing demand for tattoo removal, and yet there is little knowledge and monitoring of tattoo pigment deposition in skin layers. The purpose of this pilot study is to describe optical coherence tomography image characteristics of intradermal tattoos. METHODS: We included five black tattoos in 3 female volunteers, 39, 35 and 30 years old. In vivo imaging of tattoo pigments in the skin is possible with optical coherence tomography (OCT), a novel non-invasive, in vivo optical imaging technology with a resolution and a penetration in skin high enough for visualization of tattoo pigment in the dermis. RESULTS: In optical coherence tomography images tattoo pigments clusters appear as dark, homogenous vertical columns and structures in the papillary dermis. OCT-scanned normal skin (without tattoos) appeared to be free of this dark structure. CONCLUSION: We have demonstrated that OCT can be used to visualize clusters of light absorbing pigments in a predictable manner.     

Hidradenitis suppurativa: an update on epidemiology,phenotypes, diagnosis,pathogenesis, comorbidities and quality of life

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that severely impairs patients' quality of life. It is characterized by recurrent painful nodules, abscesses and draining sinus tracts in primarily intertriginous areas. We aimed to review the most up‐to‐date information regarding the epidemiology, clinical presentation, diagnostic studies, pathogenesis, comorbidities and quality of life of patients with hidradenitis suppurativa. We performed a systematic search of Medline, Embase database (from inception to September 2019) and review of bibliographies without restrictions on year or language. HS has an estimated global prevalence of 0.00033–4.1% (but most likely 0.7–1.2% in the European‐US population). Patients still experience a significant diagnostic delay, up to several years. In the absence of pathognomonic tests, the diagnosis of HS is made from clinical observation and the disease narrative. Phenotypic variation renders diagnosis and severity assessment difficult. Ultrasound imaging is an emerging assessment tool for deep‐seated lesions. The Hurley Staging System is still widely used in severity rating. Follicular hyperkeratosis and dilatation, follicular rupture and chronic inflammation with architectural tissue changes have been implicated in the pathogenesis of HS. HS has been associated with metabolic syndrome and other risk factors for cardiovascular disease, diabetes mellitus type II, polycystic ovarian syndrome, depression, suicide and substance use disorders. It has been linked to other immune‐mediated diseases such as inflammatory bowel disease and spondyloarthropathy. Pain, pruritus, malodour, low self‐esteem, sleep and sexual dysfunctions, and poor mental health are chronic symptoms or consequences of uncontrolled disease. HS is an under‐diagnosed and under‐treated disease with a profound negative impact on patients' quality of life. In the light of its associated comorbidities, an interdisciplinary management approach may be needed to ensure the best outcomes.     

Eruptive Melanocytic Nevi: A Review

Eruptive melanocytic nevi (EMN) is a phenomenon characterized by the sudden onset of nevi. Our objective was to compile all published reports of EMN to identify possible precipitating factors and to evaluate the clinical appearance and course. We conducted a systematic bibliographic search and selected 93 articles, representing 179 patients with EMN. The suspected causes were skin and other diseases (50%); immunosuppressive agents, chemotherapy or melanotan (41%); and miscellaneous, including idiopathic (9%). The clinical manifestations could largely be divided into two categories: EMN associated with skin diseases were frequently few in number (fewer than ten nevi), large, and localized to the site of previous skin disease, whereas those due to other causes presented most often with multiple small widespread nevi. In general, EMN seem to persist unchanged after their appearance, but development over several years or fading has also been reported. Overall, 16% of the cases had at least one histologically confirmed dysplastic nevus. Five cases of associated melanoma were reported. We conclude that the clinical appearance of EMN may differ according to the suggested triggering factor. Based on the clinical distinction, we propose a new subclassification of EMN: (1) widespread eruptive nevi (WEN), with numerous small nevi, triggered by, for example, drugs and internal diseases, and (2) Köbner-like eruptive nevi, often with big and few nevi, associated with skin diseases and most often localized at the site of previous skin disease/trauma. The nature of the data precluded assessment of risk of malignant transformation.

     

Ultrasound as a Diagnostic Aid in Identifying Neurofibromas

Neurofibromatosis 1 is a multisystem disorder associated with substantial clinical variability. During childhood, few neurofibromas and café au lait spots may be the only manifest symptoms, making correct and timely diagnosis difficult. Herein we describe the clinical usefulness of ultrasound examination in identifying neurofibromas.     

High‐definition optical coherence tomography enables visualization of individual cells in healthy skin: comparison to reflectance confocal microscopy

High‐definition OCT (HD‐OCT) is an innovative technique based on the principle of conventional OCT. Our objective was to test the resolution and image quality of HD‐OCT in comparison with reflectance confocal microscopy (RCM) of healthy skin. Firstly, images have been made of a ultra‐high‐resolution line‐pair phantome with both systems. Secondly, we investigated 21 healthy volunteers of different phototypes with HD‐OCT and RCM on volar forearm and compared the generated images. HD‐OCT displays also differences depending on the skin phototype and anatomical site. The 3‐μm lateral resolution of the HD‐OCT could be confirmed by the phantom analysis. The identification of cells in the epidermis can be made by both techniques. RCM offers the best lateral resolution, and HD‐OCT has the best penetration depth, providing images of individual cells deeper within the dermis. Eccrine ducts and hair shafts with pilosebaceous units can be observed depending on skin site. HD‐OCT provides morphological imaging with sufficient resolution and penetration depth to permit visualization of individual cells at up to 570 μm in depth offering the possibility of additional structural information complementary to that of RCM. HD‐OCT further has the possibility for rapid three‐dimensional imaging.