Abstract:

Sebaceous carcinoma (SC) is a rare, but potentially deadly form of skin cancer. Due to its similarity in clinical appearance to benign entities, diagnosis of SC can be challenging, leading to missed or delayed diagnosis. Clinical behavior is also highly variable, ranging from relatively indolent to aggressive, metastatic disease. Given the ambiguity of clinical features and variable disease course, histological examination of possible SC is crucial. In this study, we aimed to elucidate the relationship between the histopathological features and immunohistochemical markers of SC with the clinical outcomes of cancer recurrence and metastasis. A single-center, retrospective chart review of 27 SC cases was performed. Clinical characteristics such as patient demographics, tumor location, treatment modality, and outcome were assessed. Histopathologically, features including the degree of differentiation, growth pattern, presence of perineural or lymphovascular invasion, and presence of pagetoid spread or comedonecrosis were evaluated. Immunohistochemical profile including adipophilin, androgen receptor, and MSH2/MSH6 was reviewed. Cases with a ‘good outcome’ were defined as having a full remission after treatment. ‘Poor outcome’ cases were defined as those with recurrence or metastasis following initial treatment. Most of the tumors were well-differentiated with a lobular growth pattern. Factors associated with a poor outcome included cystic appearance, perineural invasion, and comedonecrosis. Although the lobular growth pattern was the most common, the papillary growth pattern was more frequently seen in poor outcome cases. Additionally, loss of MSH2 and MLH6 staining was increased in poor outcome cases, although presence of Muir-Torre syndrome was rare in this study.

Financial Disclosure:
No current or relevant financial relationships exist.