JAMES M.GRICHNIKMD, PhDASHFAQ A.MARGHOOBMDALONSCOPEMD
The main diagnostic criteria for seborrheic keratosis (SK) in dermoscopy include the presence of fissures and ridges, milialike cysts, and comedolike openings. Looped (“hairpin”) vessels are often associated with SK and may be of additional diagnostic value.1 Hairpin vessels can occasionally be observed in other skin tumors such as keratoacanthomas, basal cell carcinomas, and melanomas.2 Reflectance confocal microscopy (RCM) of SK shows a cerebriform appearance of the skin surface, with bulbous projections and round to linear keratin-filled invaginations.3 At the dermoepidermal junction, cords and dermal papillae of different sizes and shapes are noted. Highly reflective round structures, corresponding to milialike cysts, are commonly seen. The blood flow within dermal papillae can be observed by in vivo RCM. We describe 2 cases of SK showing typical vascular features on dermoscopy and on RCM.
Ahlgrimm-Siess V, Cao T, Oliviero M, Hofmann-Wellenhof R, Rabinovitz HS, Scope A. The Vasculature of Nonmelanocytic Skin Tumors in Reflectance Confocal Microscopy, II: Vascular Features of Seborrheic Keratosis. Arch Dermatol. 2010;146(6):694-695. doi:10.1001/archdermatol.2010.123