A 38-year-old woman presented since birth a localised parietal hairless orange-yellow plaque (1) This plaque was smooth and became verrucous during childhood.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.
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Litterature
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