Adenoma with clear cell change of the large intestine

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.

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.

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.

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.