Nevus sebaceus of Jadassohn - high frequency ultrasound imaging and videodermoscopy examination. Case presentation.

Nevus sebaceus of Jadassohn (NSJ) is a congenital cutaneous hamartoma mainly developing from pilosebaceous unit cells. NSJ has the potential to develop into a variety of benign and malignant tumors, which are not limited to sebaceous differentiation. The dynamical monitoring for the earliest malignant transformation is necessary.