Long-term evolution pleomorphic adenoma: diagnostic value of DNA ploidy analysis and topographic malignization pattern

Objective: To present a case of submandibular long-term evolution pleomorphic adenoma (PA). There is little information about topographic malignization patterns of PA. Case report: A giant tumor of 25 years evolution was analized; DNA ploidy was evaluated in different superficial and deep areas using flow cytometry analysis, and correlation with pathological and immunohistochemical characteristics was made. Superficial areas exhibited a typical histological PA pattern and were DNA diploid. Deep samples showed DNA aneuploidy, atyphical histological benign features and expression of markers involved at an early stage malignization, as p53 and Ki67. Conclusions: These findings revealed that deep tumor compartments may be involved in the initial stages of malignant transformation. DNA ploidy analysis may provide an additional diagnosis tool and indicate “uncertain” areas that require careful study to avoid diagnostic errors. Further, larger studies are needed to confirm our results and to evaluate the usefulness of the technique.