Role of computed quantitation of immunohistochemical staining of Ki-67 antigen in diagnosing ampullary lesions

OBJECTIVE: To determine the possible role of Ki-67 antigen expression by visual and computed quantitation in diagnosing ampullary lesions. STUDY DESIGN: Twenty-two cases of ampullary lesions treated at Thomas Jefferson University Hospital between 1989 and 1994 were analyzed. Four cases of adenoma, 4 of epithelial dysplasia in adenoma, 7 of well-differentiated adenocarcinoma and 7 of high grade adenocarcinoma were included. For each case three consecutive sections were obtained from the paraffin-embedded blocks. The first slide was stained with hematoxylin and eosin for visual diagnosis; the other two were immunoprocessed to evaluate the expression of Ki-67 antigen. Visual quantitation of Ki-67 was evaluated by light microscopy, and computed quantitation was performed utilizing the SAMBA 4000 cell image analysis systems. RESULTS: Immunohistochemical analysis of the ampullary lesions showed a positive correlation of Ki-67 expression, both by visual and computed quantitation, with biologic grade. The cell proliferation sequence was carcinoma, adenoma with dysplasia and adenoma. CONCLUSION: Ki- 67 antigen expression correlated highly with the progression of malignancy in ampullary lesions. Computed quantitation of Ki-67 was more sensitive than visual quantitation, especially in differentiating between low and high grade adenocarcinomas.