Adenoma with clear cell change of the large intestine

Background and Objectives: Clear cell change of the large intestinal neoplasm is rare, and its character remains unclear. We report a case of the large intestinal adenoma with clear cell change with immunohistochemical and molecular studies to investigate whether the clear cell change is associated with a malignant progression of the adenoma. Methods We studied the histochemical and immunohistochemical staining characteristics of the tumor by staining with hematoxylin‐eosin, periodic acid‐Schiff, alcian blue, and by immunostaining using antibodies against carcinoembryonic antigen, epithelial membrane antigen, p53, and Ki‐67. The c‐K‐ras codon 12 point mutations were analyzed using a nonradioactive restriction fragment length polymorphism technique. Results The tumor was composed of a typical tubular adenoma and a tubular adenoma with clear cytoplasm. The clear cytoplasm was negative by mucin stains. Immunohistochemically p53 was negative in both the components. Labeling index of Ki‐67 showed no significant difference between the two components. No codon 12 mutation of c‐K‐ras gene was observed in both the components. Conclusion These findings suggest that the clear cell change of the tubular adenoma is not associated with a malignant progression in adenoma‐carcinoma sequence involving c‐K‐ras and p53. J. Surg. Oncol. 1998;67:182–185. © 1998 Wiley‐Liss, Inc.