Verruca Vulgaris Key Points Verruca vulgaris (common wart) is a benign growth in the epidermis caused by localized infection with one of the many types of human papillomavirus (HPV) HPV…

Xanthelasma Palpebrarum Key Points Xanthelasma is a condition characterized by the development of flat yellowish papules or plaques near the medial canthal region in the upper or lower eyelids or…

Trachoma Key Points Trachoma is a chlamydial infection characterized by recurrent episodes of conjunctival inflammation with lymphoid follicles and, in some cases, severe papillary hypertrophy Chlamydial antigens are believed to…

Syringoma Key Points Syringoma is a benign adnexal tumor derived from the intraepidermal eccrine duct It can be associated with several systemic syndromes including diabetes mellitus, Down syndrome, Brooke-Spiegler syndrome,…

Syringocystadenoma Papilliferum Key Points Syringocystadenoma papilliferum (SCAP) is a benign adnexal skin tumor presenting as a proliferating lesion of apocrine, eccrine, or pluripotential appendageal cells, mostly located on the head…

Stevens-Johnson Syndrome Key Points Stevens-Johnson syndrome (SJS) is a severe T-cell-mediated, usually drug-induced, acute blistering disease of the skin SJS, together with toxic epidermal necrolysis, represents a wide spectrum of…

Subepidermal Calcinosis Key Points Subepidermal calcinosis is a form of localized cutaneous soft tissue calcium deposit It is classified as dystrophic, metastatic, calciphylaxis, iatrogenic, and idiopathic types The pathogenesis is…

Solitary Fibrous Tumor Key Points Solitary fibrous tumor (SFT), previously known as hemangiopericytoma, comprises a histologic spectrum of fibroblastic mesenchymal neoplasms The SFT group includes SFT and related lesions ranging…

Seborrheic Keratosis Key Points Seborrheic keratosis (SK) is the most common benign epithelial tumor and accounts for about 20% of benign epithelial neoplasms seen on the eyelid The pathogenesis of…

Sebaceous Duct Cyst Key Points Sebaceous duct cysts are sporadic, superficial cutaneous cysts caused by obstruction of the outflow duct of the sebaceous glands associated with the pilosebaceous follicular unit…