A 21-year-old man presents to the clinic requesting removal of a growth on his scalp. He believes that the lesion has been present since birth and states that it has gradually increased in size over the years. Because of the size of the lesion, it is often traumatized during hair combing; otherwise, the lesion is asymptomatic. The patient’s family history is negative for skin cancer. He is in good health and takes no medications. Physical examination reveals a 1.4-cm firm, flesh-colored plaque. No similar lesions are noted elsewhere.
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Nevus sebaceous is a benign hamartoma first described in 1895 by the German dermatologist Josef Jadassohn (nevus sebaceous of Jadassohn).1 Studies suggest that causality may be linked to specific gene mutations (KRAS and HRAS).2,3 The lesion most commonly presents on the scalp or face as a waxy flesh-toned to yellowish patch or plaque. Lesions are usually noted at birth or shortly thereafter. With puberty, nevus sebaceous becomes more prominent and often develops a verrucoid appearance later in life. The lesions are devoid of hair.
The condition is not associated with systemic abnormality; a rare variant, linear nevus sebaceous syndrome (Schimmelpenning syndrome), is marked by skeletal changes, seizures, and ocular anomalies.4
Microscopic examination reveals abundant sebaceous glands, immature and defective hair follicles, and papillomatous epidermal hyperplasia. A number of benign and malignant neoplasms may arise from nevus sebaceous lesions, which first become apparent after puberty.5 The most common neoplasms include benign syringocystadenoma papilliferum, benign trichoblastoma, and basal cell carcinoma. Sebaceous carcinoma is a rare malignant tumor that arises in nevus sebaceous.6
Lesions are often surgically removed for cosmetic reasons; some clinicians advocate early prophylactic excision to prevent malignant transformation.6 However, the risk of an associated malignancy is quite low, low-grade in nature, and occurs primarily in middle-aged to older adults.7,8
Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Geisinger Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
- Baigrie D, Troxell T, Cook C. Nevus sebaceus. In: StatPearls [Internet]. StatPearls Publishing; 2022. Updated April 30, 2022.
- Lihua J, Feng G, Shanshan M, Jialu X, Kewen J. Somatic KRAS mutation in an infant with linear nevus sebaceous syndrome associated with lymphatic malformations: a case report and literature review. Medicine (Baltimore). 2017;96:e8016. doi:10.1097/MD.0000000000008016
- Hsu CK, Saito R, Nanda A, et al. Systematised naevus sebaceus resulting from post-zygotic mutation in HRAS. Australas J Dermatol. 2017;58(1):58-60. doi:10.1111/ajd.12399
- Kuok C, Chan K. Renal involvement in linear nevus sebaceous syndrome-an underrecognized feature. Pediatr Rep. 2021;13(2):203-209. doi:10.3390/pediatric13020028
- Kaddu S, Schaeppi H, Kerl H, Soyer HP. Basaloid neoplasms in nevus sebaceus. J Cutan Pathol. 2000;27(7):327-337. doi:10.1034/j.1600-0560.2000.027007327.x
- Morimura S, Tomita Y, Ansai S, Sugaya M. Secondary malignant tumors arising in nevus sebaceus: two case reports. Diagnostics (Basel). 2022 Jun 13;12(6):1448. doi:10.3390/diagnostics12061448
- Santibanez-Gallerani A, Marshall D, Duarte AM, Melnick SJ, Thaller S. Should nevus sebaceus of Jadassohn in children be excised? A study of 757 cases and literature review. J Craniofac Surg. 2003;14(5):658-660. doi:10.1097/00001665-200309000-00010
- Hsu MC, Liau JY, Hong JL, et al. Secondary neoplasms arising from nevus sebaceus: a retrospective study of 450 cases in Taiwan. J Dermatol. 2016;43(2):175-180. doi:10.1111/1346-8138.13070