Immunohistochemical characterization of sebaceous epithelioma in two dogs

This report describes two cases of sebaceous epithelioma and its immunohistochemical characterization with CK 14, CK18, p63, Ki67 and Bcl-2 immunostaining. Case 1 was a 12-year-old, intact English Cocker spaniel female presenting with multiple skin nodules over one year. Case 2 was a 7-year-old, spayed poodle female with a five-month history of solitary mass. Hematoxylin and eosin (H & E) staining showed that the nodules in both cases were irregular lobules comprised of epithelial cells around well differentiated sebocytes. Neoplastic cells were positive for CK14 and p63 but were negative for CK18 cell marker. In addition, immunostaining for Ki67 proliferation marker showed 13.1% and 12.4% positive cells in the two cases, respectively. Furthermore, Bcl-2, which is highly expressed in human benign sebaceous tumors, was seen in basaloid cell nuclei and cytoplasm. CK14, CK18, p63, Ki67, and Bcl-2 antibody application provided further information for diagnosing sebaceous epithelioma and for prognosis in these two cases.