The correct answer is A:This is a benign nevus sebaceous of Jadassohn. It carries a low risk of basal cell carcinoma development. Observation is recommended, not immediate excision.
A neonate is noted to have a soft, yellowish-colored plaque on the temple.
Discussion: This is such a classic-appearing lesion that developing a comprehensive differential diagnosis is unnecessary. The nevus sebaceous (NS) is a well-known congenital cutaneous hamartoma composed of both ectodermal and mesodermal structures and typically affecting the scalp or face. The predominance of sebaceous glands within the lesion accounts for the characteristic yellow to orange-brown color. This hamartoma appears in about 0.3% of all neonates.[1] During infancy and childhood, the lesion remains relatively static. However, at or near puberty and throughout adulthood, the lesion can be expected to thicken and usually becomes increasingly more verrucous in nature.
While statistics are somewhat uncertain, secondary benign and malignant neoplasms arise within NS in adults in about 15% of cases.[2] Such secondary neoplasms are quite uncommon in both prepubertal children and adolescents.
Benign secondary lesions that develop in NS include: syringocystadenoma papilliferum (most commonly), trichoblastoma, trichilemmoma, sebaceoma, seborrheic keratosis, syringoma, follicular poroma, nodular hidradenoma, and apocrine cystadenoma.[3] Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the usual malignant growths that may appear. Due to the retrospective nature of the data available, it is difficult to ascertain the precise risk of malignant tumors arising within an NS; however, it is now generally thought that the risk of BCC is under 2%.[4] The risk of SCC is actually rather negligible. For example, in a series of 997 NS reported from the Armed Forces Institute of Pathology, only two SCC were identified.[5] Several additional series of NS have been reported without a single instance of SCC developing.[2,6,7]
Due to the potential for the development of malignant neoplasms, early excision of NS in childhood has traditionally been recommended. However, in the last several decades, this suggestion gradually has been dropped because:
1. Malignant tumors are only exceptionally observed in children.
2. True malignant tumors are less common than previously thought, even in adulthood.
3. Even if malignancy appears, the overwhelming likelihood is that it would be a BCC posing no serious danger if properly managed.
If an NS is excised, this is generally done for cosmetic reasons. Small lesions can be excised with primary closure. Larger lesions may require grafting or employment of rotation, transposition, or island flaps.[8]
In summary, the nevus sebaceous should be regarded as a benign lesion that only rarely undergoes any form of malignant transformation. For this reason, surgical excision is more an aesthetic procedure than a preventive treatment. When parents (or an adult patient) ask for medical advice, they should be informed about how exceptional it is for true life-threatening tumors to arise in NS. Aesthetic concerns or anxiety due to cancerphobia should be weighed against the morbidity of surgical intervention (bleeding, infection, scarring, general anesthesia), especially if excision is being considered in a pediatric patient.
References
1. Stavrianeas NG, Katoulis AC, Stratigeas NP, et al. Development of multiple tumors in a sebaceous nevus of Jadassohn. Dermatology. 1997;195:155–158.
2. Cribier B, Scrivener Y, Grosshans E. Tumors arising in nevus sebaceous: a study of 596 cases. J Am Acad Dermatol. 2000;42:263–268.
3. Aguayo R, Pallares J, Casanova JM, et al. Squamous cell carcinoma developing in Jadassohn's sebaceous nevus: Case report and review of the literature. Dermatol Surg. 2010;35:1763-1768.
4. Rosen H, Schmidt B, Lam HP, et al. Management of nevus sebaceous and the risk of basal cell carcinoma: an 18-year review. Pediatr Dermatol. 2009;26:676–681.
5. Domingo J, Helwig EB. Malignant neoplasms associated with nevus sebaceous of Jadassohn. J Am Acad Dermatol. 1979;1:546–556.
6. Weng Ch, Tsai Y, Chen T. Jadassohn's nevus sebaceous of the head and face. Ann Plast Surg. 1990;25:100–102.
7. Chun K, Vazquez M, Sanchez JL. Nevus sebaceous: Clinical outcome and considerations for prophylactic excision. Int J Dermatol. 1995;34:538–541.
8. Davison SP, Khachemoune A, Yu D, et al. Nevus sebaceous of Jadassohn revisited with reconstruction options. Int J Dermatol. 2005;44;145–150.
