Periungual fibroma (Koenen tumors) as isolated sign of tuberous sclerosis complex with tuberous sclerosis complex 1 germline mutation - Quist, Sven Roy; Franke, Ingolf; Sutter, Christian; Bartram, Claus R.; Gollnick, Harald P.; Leverkus, Martin (Journal of the American Academy of Dermatology, 2010)