The dermoscopic variability of dermatofibromas

Features of dermatofibroma in reflectance confocal microscopy

BACKGROUND

Dermatofibroma (DF) is a common benign skin lesion in a majority of cases located on the legs or upper limbs. The etiology of DF is still unclear.

OBJECTIVES

Reflectance confocal microscopy features of DF were described.

METHODS

Forty patients with DF diagnosis confirmed by dermoscopy were examined using reflectance confocal microscopy VivaScope 1500 from March 2018 to April 2019.

RESULTS

DF was more common in females (80%) than males (20%). Thirty-six lesions (90%) were located on the limbs while four (10%) were on the trunk. Dermoscopically, 18 lesions (45%) revealed typical features: central white area with a brown network in the periphery. Twenty-two DFs (55%) were found with a central white patch and globular-like structures, surrounded by a thin brown network. In reflectance confocal microscopy, all revealed a typical honeycombed pattern, although in some cases (30%), streaming was observed. In two lesions (5%) in epidermis, few dendritic cells were observed, and one DF revealed roundish pagetoid cells (2.5%). The dermoepidermal junction (DEJ) in all lesions was abounded in dilated vessels. The most common observable feature of DF was bright "rings" composed of monomorphic, regular cells surrounding dark dermal papillae. In five lesions (12.5%), rings were "double" because of exceptionally pigmented DF.

CONCLUSION

Reflectance confocal microscopy enables us to describe microscopic features of DF. There are four confocal microscopic features observable in each DF: in the epidermis, normal honeycombed pattern, sometimes with local streaming, in DEJ, edged papillae, bright rings, and dilated vessels.

Dermoscopic features of livedoid vasculopathy

Livedoid vasculopathy (atrophie blanche) is a form of thrombotic vasculopathy. It is characterized by small ulcers that become crusted, and heal after several months to produce white atrophic scars. The most commonly affected sites are the lower legs, in particular the dorsum of the feet and ankles. To date, the dermoscopic features of livedoid vasculopathy have not been clearly described in the literature. In this observational study, we sought to evaluate the dermoscopic patterns of livedoid vasculopathy and determine whether the dermoscopic features are associated with certain histopathological characteristics. We evaluated 9 patients with livedoid vasculopathy by dermoscopy. Skin biopsy specimens were stained with hematoxylin and eosin for histopathologic examination, and dermoscopic features were correlated with histopathological characteristics. In the majority of patients with livedoid vasculopathy, examination with dermoscopy revealed central crusted ulcers or ivory white areas associated with peripheral pigmentation in a reticular pattern. In addition, increased vascular structures including linear and glomerular vessels were found. On histopathological examination, the central ivory white areas correlated with dermal fibrosis, the reticular pigmentation corresponded to epidermal basal layer hyperpigmentation or melanin within melanophages in the dermal papillae, and the vascular structures correlated with dilatation and proliferation of capillaries in the upper dermis. In summary, the most common dermoscopic features of livedoid vasculopathy identified in this study were central crusted ulcers or ivory white scar-like areas associated with peripheral reticular pigmentation and increased vascular structures. The characterization of dermoscopic criteria for livedoid vasculopathy may improve the accuracy in the clinical diagnosis and follow-up of this disease.

An Atrophic Plaque with Arborizing Vessels

Dermatofibromas are a common finding in the daily clinical practice. Most lesions are found incidentally or because patients seek medical attention due to the aspect of the lesion. Rare variants of dermatofibroma such as aneurismatic or atrophic dermatofibroma can be encountered simultaneously; thus, these combined features may raise the possibility of other diagnoses to be considered. By providing diverse clinical and dermoscopic examples of dermatofibromas, we may prevent misdiagnosing these lesions. This case illustrates how two rare variants of dermatofibroma can coexist. Clinical presentation of dermatofibromas may vary greatly, and it is essential for dermatologists to recognize them clinically and dermoscopically before obtaining histopathological diagnosis.