Nevus Sebaceous is a hamartoma composed of sebaceous glands, also known as an organoid nevus.

bubble_chart Pathological Changes

The histological changes with age can generally be divided into three stages. In infancy or childhood, the epidermis exhibits grade I hyperplasia along with small, incompletely differentiated hair follicle structures, while the sebaceous glands are underdeveloped. During adolescence, the epidermis shows verrucous or papillomatous hyperplasia, with numerous mature or nearly mature sebaceous glands in the dermis. Well-developed profuse sweating glands can be observed in the deep dermis or subcutaneous fat beneath the sebaceous gland lobules. In the late stage [third stage] of the lesions, there is a tendency for adnexal tumors to develop, with basal cell carcinoma occurring in approximately 10–15% of cases.

bubble_chart Clinical Manifestations

Sebaceous nevus is relatively common, often appearing at birth or shortly after, and is frequently found on the head and neck, particularly the scalp. Most cases are solitary, with a few being multiple. The rash presents as well-defined, raised small nodules with a round shape, ranging from pale yellow to gray-brown, and has a waxy appearance. Scalp lesions typically lack hair growth. During adolescence, the lesions thicken and expand, becoming more papillomatous in appearance with a pronounced yellow hue. In adults, sebaceous nevus becomes verrucous and firm in texture. A small number of patients may develop adnexal tumors, such as sweat gland tumors, or even metastasis on the basis of this condition.

bubble_chart Treatment Measures

To prevent the occurrence of tumors, complete surgical removal is necessary, and treatments such as electrocoagulation and laser therapy can also be performed.

The diagnosis is usually straightforward based on the age of onset, the typical locations of the rash, and its appearance. However, differentiation from juvenile xanthogranuloma, verrucous nevus, or syringocystadenoma papilliferum may sometimes be necessary, in which case a pathological examination is required.