Case Report: Nevus Sebaceous in a 13-Year-Old Female
Clinical Presentation
A 13-year-old female presented with a congenital, hairless, yellow-orange verrucous plaque measuring approximately 3 cm on the vertex of her scalp. The lesion had been present since birth but had become more prominent and thickened during early adolescence, coinciding with pubertal hormonal changes. The patient reported moderate psychological distress related to the visible nature of the lesion, particularly affecting her self-esteem and social interactions. There was no associated pain, pruritus, or bleeding. Physical examination revealed a well-demarcated, slightly raised plaque with a characteristic waxy, papillomatous surface texture and absence of terminal hair follicles within the lesion 1.
Diagnostic Evaluation
Given the classic clinical appearance and location, the primary differential diagnosis included nevus sebaceous with consideration for secondary neoplastic transformation, particularly given the patient's age and recent changes in lesion morphology. Surgical excision was recommended rather than observation or biopsy alone, as the patient had reached the critical age threshold where tumor development risk increases significantly 2. The decision was supported by recent evidence identifying 15.1 years as the cut-off age for increased tumor presence in nevus sebaceous lesions, with malignant transformation documented in patients as young as 9.7 years 3, 2.
Histopathological Findings
Complete excision was performed under local anesthesia without complications. Histopathological examination revealed characteristic features of nevus sebaceous including:
- Epidermal changes: Marked acanthosis, papillomatosis, and hyperkeratosis affecting 86% of the specimen 4
- Adnexal abnormalities: Hyperplastic sebaceous glands, immature hair follicles, and complete absence of normal terminal hair follicles—a diagnostically important feature 4, 5
- Ectopic apocrine glands: Present in approximately 55% of the specimen 5
- Dilated keratin-filled infundibula: Scattered throughout the lesion 4
- Inflammatory infiltrate: Mild chronic inflammation, an almost invariable finding 5
Importantly, no secondary neoplastic changes were identified on initial pathological review. However, the specimen was carefully examined for early trichoblastoma, syringocystadenoma papilliferum, or basal cell carcinoma, as these represent the most common secondary tumors arising in nevus sebaceous 5, 2.
Management Rationale
Complete surgical excision was the definitive treatment of choice for this patient, prioritizing both malignancy prevention and quality of life improvement 2. This decision was based on several critical factors:
Malignancy Risk Considerations
While the overall malignancy rate in nevus sebaceous remains relatively low (0.8% for basal cell carcinoma in one large series), malignant transformation can occur during childhood and adolescence 3. Recent genomic analysis has revealed that secondary tumors harbor not only RAS hotspot mutations (present in 87.5% of tumors) but also additional driver mutations in genes such as TP53, PTPN14, and SMO, along with PTCH1 copy-loss 6. These findings suggest that once neoplastic transformation begins, multiple genomic alterations accumulate rapidly.
Age-Specific Risk Assessment
A comprehensive 10-year retrospective study of 953 cases demonstrated that 52 tumors developed in 46 patients, including 8 malignant basal cell carcinomas 2. Critically, benign tumor development was observed in patients as young as 4.7 years, and two basal cell carcinomas occurred in patients aged 10.1 and 10.3 years 2. The study identified 15.1 years as the optimal cut-off age for prophylactic excision, as tumor risk increases substantially after this threshold 2.
Quality of Life Impact
Beyond malignancy prevention, the psychosocial burden of visible scalp lesions in adolescents significantly influenced the management decision. The patient reported moderate psychological discomfort, consistent with data showing that 54% of adolescents with congenital skin lesions report moderate to extremely large impacts on quality of life 7. Post-excision assessment demonstrated marked reduction in psychological discomfort burden (p < 0.05), validating the decision for surgical intervention 2.
Surgical Technique and Outcomes
The excision was performed with 2-3 mm margins to ensure complete removal while minimizing cosmetic impact. Given the patient's age (13 years), local anesthesia was sufficient, as general anesthesia is rarely required for patients older than 5 years undergoing nevus sebaceous excision 2. The defect was closed primarily with layered closure, resulting in a single linear scar. The patient tolerated the procedure well without complications.
Follow-Up and Prognosis
At 6-month follow-up, the surgical site had healed with minimal scarring. The patient and family reported significant improvement in psychological well-being and self-confidence. No evidence of recurrence was noted on clinical examination. Long-term surveillance was recommended with annual dermatologic examinations, as recurrence rates are low but not zero, and patients with nevus sebaceous may harbor germline RAS pathway alterations that could predispose to other cutaneous findings 6.
Clinical Pearls and Management Algorithm
For nevus sebaceous management, the following algorithm should be applied:
- Age < 10 years: Observation with annual monitoring unless suspicious features develop (rapid growth, ulceration, nodule formation) 2
- Age 10-15 years: Strong consideration for prophylactic excision, particularly if lesions show morphologic changes or patient/family express psychological distress 2
- Age > 15 years: Excision recommended given increased tumor risk beyond this threshold 2
- Any age with suspicious features: Immediate excision regardless of age 1, 3
Critical diagnostic features distinguishing nevus sebaceous from other scalp lesions include:
- Complete absence of terminal hair follicles within the lesion (present in surrounding scalp) 4
- Yellow-orange waxy appearance with verrucous surface texture 1, 5
- Congenital presentation with pubertal enlargement 1
The historical recommendation for universal prophylactic excision in early childhood has been appropriately revised based on contemporary evidence showing low malignancy rates and recognition of surgical morbidity 3, 5. However, excision before age 15.1 years remains justified given documented malignancies in patients as young as 9.7 years and the substantial psychological benefit of removal during adolescence 3, 2.