Pleomorphic Adenoma And Adenoid-Cystic Carcinoma Of Salivary Glands.
AN IMMUNOHISTOCHEMICAL AND FLOW-CYTOMETRIC STUDY. A. Russo*, V. Bazan, V. Morello (1), E. Danicle (1), and R. M. Tomasino (1), Institute of Pathology "R" (1), Section of Experimental Oncology, Department of Clinical Oncology Research, University of Palermo, (Italy).
Thirty-two pleomorphic adenomas (PAs) and 7 adenoid cystic carcinomas (ACCs) were studied by immunohistochemistry and by DNA flow cytometry. Proliferating cell nuclear antigen (PCNA) indices, DNA-ploidy and S-phase fraction (SPF) were determined in order to analyze their possible relationships with the clinico-pathological variables and to clarify the reasons for the biological differences of these neoplasias. The PAs were divided into three groups, mainly epithelial, myxoid and chondroid; PCNA labeling index (LI), weighted mean index (WI) and the WI/LI ratio were assessed in the predominant components; a single PCNA index, weighted by the percentage of each component, was also calculated. Only WI/LI was found to be significantly different in the three components, while PCNA single index did not show either significant differences by sex, age, site and size, or any correlation with the SPF. Three of the 7 ACCs and only one of the 32 PAs showed DNA-aneuploidy. Significant differences were found between PAs and ACCs by site (p < 0.01) and DNA ploidy (p < 0.05); furthermore, all PCNA indices (single index) were significantly lower in PAs than in ACCs, whereas SPF values were not significant, though the median in ACCs was double that of the PAs (7.6% versus 3.6%).