The patient consulted because of the occurence of nodules (2) on the anterior part of the lesion.
Dermoscopy revealed yellow globular-like structures (1) on the posterior area.
On the nodules, arborizing tree vessels and blue ovoid nests were in favour of a basal cell carcinoma or a trichoblastoma
This lesion was biopsied and pathology confirmed the diagnosis of basal cell carcinoma occuring on a Jadahsson nevus (nevus sebaceus)
Knowing that trichoblastomas are the tumors the most frequently reported as complication of nevus sebaceous (2, 3) and that dermoscopy is not sufficently discriminative to distinguish a trichoblastoma from a basal cell carcinoma, we have to wait for the pathology result of the entire excision.
An update will be added within a month.
1 -Nancy H. Kim et al. The dermoscopic differential diagnosis of yellow lobularlike structures. Arch Dermatol 2008; 144 (7): 962.
2-Jaqueti et Al. Trichobastoma is the most common neoplasm debeloped in nevus sebaceus of Jadassohn: a clinicopathologic study of a series of 155 cases. Am J Dermatopathol 2000;22(2):108-18
3- Cribier et Al. Tumors arising in nevus sebaceus. A study of 596 cases. J Am Acad Dermatol 2000;42:263-8