Photo Rounds

Growth on scalp

A 14-year-old boy visited his family physician (FP) with a sprained ankle. During the visit, his father asked about a growth of bumpy skin on his son’s scalp. The father said that the growth on the scalp had been there since early childhood, but had become darker and more raised over time. He also wanted to know why no hair grew on that spot. The teen said that the lesion didn’t bother him.

What’s your diagnosis?


Growth on scalp

The family physician diagnosed a nevus sebaceous (NS) in this patient.

There are 3 stages of evolution paralleling the histologic differentiation of normal sebaceous glands:

  1. Infancy and young children. The lesion is smooth to slightly papillated, waxy, and hairless. (See Photo Rounds Friday, 6/15/18.)
  2. Puberty. Epidermal hyperplasia results in verrucous irregularity of the surface and coverage with numerous closely aggregated yellow-to-brown papules (this case).
  3. Development of secondary appendageal tumors. This occurs in 20% to 30% of patients. Most lesions are benign, but single (most commonly basal cell carcinoma) or multiple malignant tumors of both epidermal and adnexal origins may be seen. These malignancies are rarely seen in childhood.

In this case, a biopsy was not needed because the clinical picture was clear and no operative intervention was planned. When needed, a shave biopsy should provide adequate tissue for diagnosis because the pathology is epidermal and in the upper dermis. The NS need not be removed to prevent malignant transformation.

The FP explained that hair usually doesn’t grow where an NS is, and it was okay to proceed with observation only. He advised the patient’s father that if any changes were to occur, he would be happy to refer the child for surgical removal. The boy was not worried about the appearance of the NS and did not want to have surgery.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Smith M. Epidermal nevus and nevus sebaceous. In: Usatine R, Smith M, Mayeaux EJ, et al. Color Atlas of Family Medicine, 2nd ed. New York, NY: McGraw-Hill; 2013:958-962.

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