Sebaceous Carcinoma : Adipophilin
Sebaceous carcinoma shows strong positivity for cytokeratins, EMA, CD15 (LeuM1), and adipophilin (shown here). It may also be positive for androgen receptors. Immunohistochemical stains for CEA and S-100 protein are negative. Adipophilin (also known as adipose differentiation-related protein and perilipin-2) belongs to the family of cytoplasmic lipid droplet binding proteins. In humans, it is encoded by the ADFP gene. This protein surrounds the lipid droplet along with phospholipids and is involved in the storage of neutral lipids within the lipid droplets. Adipophilin may be a useful marker in the identification of intracytoplasmic lipids, as seen in sebaceous lesions. It is especially helpful in identifying intracytoplasmic lipid vesicles in poorly differentiated sebaceous carcinomas in challenging cases such as small periocular biopsy specimens. Image courtesy of: Woo Cheal Cho, MD, Dept. of Pathology, Hartford Hospital, Hartford, Connecticut.