Track

Clinical Studies

Abstract

Nevus sebaceous (NS) is a type of congenital epidermal hamartoma produced by the abnormal proliferation of the pilosebaceous follicular unit, containing epidermal, apocrine, and sebaceous elements. The etiology is not completely known, but recent studies have shown that HRAS, NRAS, and KRAS genes play a role in its pathogenesis. A variety of secondary neoplasms are known to arise from NS. Most of these are benign, with trichoblastoma and syringocystadenoma papilliferum being the most common. However, malignant tumors, most often basal cell carcinoma, also occasionally arise from NS. The treatment of NS lesions is still controversial, and prophylactic removal is debated due to the possibility of malignant transformation and cosmetic concerns. Consequently, NS lesions are frequently resected with the goal of complete excision. However, assessing resection margins for residual lesions can be challenging, particularly since NS can closely resemble surrounding normal tissue during childhood, which is a commonly recommended age for excision. Therefore, we aimed to categorize the staining patterns of NS using several immunohistochemical stains, including BRAF V600E, P16, PRAME, and TdT. Although some mutations or expressions, such as TdT protein expression, have been observed in sebaceous neoplasms, no study has yet assessed these immunohistochemical expressions in these hamartomas and their possible role in margin assessment. We believe that our results could assist pathologists in assessing resection margins and contribute to the expansion of knowledge regarding the immunohistochemical and biological behavior of this entity.