Case 76 - Discussion

Uploaded: 2007-11-30, Updated: 2007-12-01

 

Nevus Sebaceus

  • Synonyms: nevus sebaceus of Jadassohn, organoid nevus, verrucous epidermal nevi, epidermal nevus syndrome;

  • Location: predilection for the scalp (vertex) and less commonly the face, the neck, or the trunk;

  • Clinical: most frequently, a solitary, hairless patch is noted on the scalp at birth or in early childhood.

  • Gross: velvety tan or orange-yellow plaque mostly on the head and the neck.

  • Nevus sebaceus passes through 3 clinically distinct stages: 1). At birth or in early infancy, nevus sebaceus appears as a hairless, solitary, linear or round, slightly raised, pinkish, yellow, orange, or tan plaque, with a smooth or somewhat velvety surface. The nevus is usually on the scalp, often near the vertex or on the face. 2). In adolescence, the lesion becomes verrucous and nodular, round, oval, or linear in shape, varying in length from about 1 cm to more than 10 cm. They most commonly occur as a single lesion, but they may be multiple and extensive. 3). Later in life, some lesions may develop various types of appendageal tumors, such as trichoblastoma; syringocystadenoma papilliferum; basal cell carcinoma; and, less commonly, nodular hidradenoma, sebaceous epithelioma, apocrine cystadenoma, eccrine carcinoma, squamous cell carcinoma, sebaceous carcinoma, spiradenoma, and keratoacanthoma.

  • Histology: Epidermis typically reveals marked acanthosis and surface papillation, which resembles seborrheic keratosis.  The dermis shows increased number of mature sebaceous glands. In childhood, the sebaceous glands in nevus sebaceous are underdeveloped, and the histologic findings may consist of only immature hair structures. In adolescents, the adnexal elements are more prominent, and are represented by sebaceous hyperplasia, apocrine proliferation, apocrine duct dilation and proliferation of eccrine glands.

  • Differential diagnoses: epidermal nevus and seborrheic keratosis, especially in inadequate samples. Nevus sebaceus is more common. More sampling may be necessary. 

References
  • AFIP, nonmelanocytic tumors of the skin, series 4;
  • http://www.emedicine.com/derm/topic296.htm