To evaluate dermoscopic features and patterns of dermatofibromas using conventional and polarized light dermoscopy. Design: Dermatofibromas were imaged using conventional nonpolarized contact dermoscopy (NPD), polarized contact dermoscopy (PCD), and polarized noncontact dermoscopy, followed by evaluation and comparison of dermoscopic features of the lesions. Setting: Dermatology clinic specializing in pigmented lesions. Patients: Fifty patients with dermatofibromas. Results: The most common features of dermatofibromas observed with NPD and PCD were central white scarlike patches (37 [74%] and 42 [84%], respectively), brown globulelike structures (21 [42%] and 22 [44%]), vascular structures (24 [48%] and 22 [44%]), and a peripheral fine pigmented network (36 [72%] for both). A newly described feature observed with PCD was a central white patch characterized by shiny white streaks. With polarized noncontact dermoscopy, the most characteristic feature was a central pink hue or "vascular blush" (44 [88%]) and visibility of blood vessels (41 [82%]). The most common pattern identified with NPD and PCD was the combination of a peripheral pigmented network and a central white patch in 28 (56%) and 31 (62%) of lesions, respectively. With polarized noncontact dermoscopy, the most common pattern was a central pink hue with a peripheral pigmented network (23 [46%]). There was good to excellent agreement when comparing NPD with PCD images, but there was a variable level of agreement when polarized noncontact dermoscopy images were compared with NPD and PCD images. Conclusions: Conventional and polarized light dermoscopy are not equivalent but may be complementary. This study highlights some salient differences. We were able to identify new dermoscopic features and patterns not previously described with conventional dermoscopy. These new criteria can aid in the diagnosis of dermatofibroma.

Sarcoidosis is a disease of uncertainty in terms of its cause, presentation, and clinical course. The disease has a worldwide distribution and affects all ages, races, and both sex. Sarcoidosis of the skin may have an extremely heterogeneous clinical presentation, so that the definitions of 'great imitator' and 'clinical chameleon' have long been used. The factors that influence clinical picture and severity of the disease are probably linked to the etiopathogenesis of sarcoidosis, which continues to be shrouded in mystery. The current state of the art on the pathogenesis of sarcoidosis is that it is an immunological response in a genetically susceptible individual to an as-yet undefined antigenic stimulus. How exposure occurs in genetically predisposed patients is not completely clear, but the most likely explanation is that these agents or antigens are either inhaled into the lungs or enter through contact with the skin, as these are the common target organs that are constantly in contact with the environment. An autoimmune etiology of sarcoidosis could possibly occur through a process of molecular mimicry of infectious or other environmental antigens to host antigens. This could lead to a cross-mediated immune response and induction of autoimmune disease. This molecular mimicry may probably be responsible for the heterogeneous clinical presentations of the disease. Several investigations and studies have provided valuable evidence on the etiopathogenesis of sarcoidosis, which may lead to the future development of targeted and innovative treatment strategies. Nevertheless, we are still a long way from unravelling the underlying cause of this mysterious disease.

Individuals tend to have one to three predominant dermoscopic nevus global patterns.