Description: Blue homogenous area.

History: The 30 years old man developed a new lesion(see blue lesion) in his Nevus sebaceus since 3 months ago. .The path report of the new lesion was a Trichoblastoma. Dermoscopic description:Blue homogenous area. Trichoblastoma arising from Nevus sebaceus. Trichoblastoma is the benign variant of Basal cell carcinoma and the most frequent benign tumor arising from Nevus sebaceus is a trichoblastoma(Iris Zalaudek-see skincancerclinic.blogspot.com/).