Sebaceous carcinoma of the eyelid

Abstract

Sebaceous carcinoma (SC) is a malignant neoplasm that frequently affects the eyelids. It is an aggressive malignancy with metastasis rates as high as 25%. Historical studies have shown that mortality rates could be as high as 83%, but with the advent of increased detection, diagnosis, and treatment options, mortality rates have dropped substantially. A major issue with obtaining a proper diagnosis of SC is that it can mimic many other benign and malignant pathologies. Consequently, a delay in the diagnosis of SC can result in a poor prognosis and outcome for patients. The standard of care for SC is surgical excision, however, there is a reoccurrence rate of approximately 4% after excision. In these cases, it is necessary to treat patients with further excision and possibly radiation. Not all patients can have their tumors treated with surgery. In cases where there is diffuse intraepithelial seeding of the tumor cells, metastasis, or orbital invasion, other methods such as chemotherapy, radiation, and exenteration must be performed. It is essential that we elucidate the cellular mechanisms regarding the etiology of SC to develop better methods of diagnosis and treatment for the future. In this chapter, we will focus on the clinically relevant topics regarding SC, signaling pathways involved in the pathogenesis, and how miRNAs interact with these cascades. Both Wnt and TGF-β signaling have been implicated in the developing sebaceous glands and SC. Several miRNAs have been studied in this disease and downstream targets include: NF-κB, PTEN, c-Myc, and AKT2. These miRNAs may be used as biomarkers for SC or they may be potential therapeutic targets for patients who do not benefit from current interventions.