Abstract
Abstract: :
Purpose:To study the role of immunohistochemical markers in the diagnosis of Adenoid Cystic Carcinoma (ACC) of the lacrimal gland and to correlate the findings with the different histopathological patterns observed. Methods:Five micra sections from twelve cases of ACC and five normal lacrimal glands were studied using a panel of ten monoclonal antibodies – pankeratin, cytokeratin 7 and 20 (CK-7 and CK-20), epithelial membrane antigen (EMA), vimentin, S100 protein and muscle specific actin (MSA). Additionally, the role of two proto-oncogenes (p53 and C-kit) and Ki-67 (proliferative index) was also examined. Positive immunostaining was scored as mild, moderate or strong and the pattern of distribution as focal or diffuse. Results:Pankeratin and CK-7 were diffusely expressed in the epithelial tubules while CK-20 was absent. EMA was focally expressed with enhancing of the ductal border as well as the intraluminal contents. Vimentin showed diffuse expresssion with moderate to strong intensity in all the tumors. MSA had a focal expression with striking staining of the myoepithelial cells located in the periphery of some of the lobules in the basaloid variant of ACC. S100 protein was expressed in most of the tumor lobules. C-kit, p53 and Ki-67 were focally expressed mostly in the basaloid variant of the ACC. The normal lacrimal gland showed a diffuse expression of pankeratin, CK-7 and S-100 protein; while vimentin was focally expressed in the mononuclear cell infiltrate amongst the acini that were non- immunoreactive. MSA vividly outlined the myoepithelial cells surrounding the lacrimal gland acini. Conclusions:Pankeratin and CK-7 are expressed diffusely in all the variants of ACC of the lacrimal gland. Focal expression of p53 and Ki-67 in the basaloid variant of ACC appears to correlate with a poor prognosis.
Keywords: tumors • immunohistochemistry • lacrimal gland