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.