Dermoscopic aspects of syringocystadenoma papilliferum associated with nevus sebaceus.

Syringocystadenoma papilliferum is a rare benign adnexal tumor that frequently shows apocrine differentiation. It usually develops on the scalp and is associated with a nevus sebaceus in 40% of cases. Although the clinical presentation may differ, its histology is characteristic. Reports have been made of dermoscopy used in cases of adnexal tumors such as eccrine poromas, hidradenomas and angiohistiocytomas; however, up to the present moment there have been no reports of dermoscopy in a case of syringocystadenoma. This paper describes the dermoscopic features found in a case of syringocystadenoma associated with a nevus sebaceus, revealing a polymorphous vascular pattern including a horseshoe-shaped arrangement of vessels.