Comparison of Cytologic and Histologic Findings in Induced Carcinoma

The hamster cheek pouch has provided a useful and a convenient tool for experimental induction of tumors because of its easy accessibility and its susceptibility to carcinogenesis. Recently, it has been used for comparing histologic and cytologic findings in induced cancer. Stahl,' following the experimental procedure outlined earlier by Salley 2 and Morris,3 studied sequential epithelial changes in the hamster pouch after biweekly applications of 0.5 percent 9, 10-dimethylbenz anthracene solution. By using a serially independent method of taking smears and biopsy specimens, he correlated the cytologic changes with histologic alterations in the carcinogen-treated hamster pouch at certain specified time intervals. He concluded that a consistently high correlation existed between cytologic and biopsy diagnoses. He further claimed that experimental cytology revealed cellular atypia before clinical recognition of the lesion and at a time when the histologic alterations were still confined to the epithelial layers. Camilleri and Smith,4 using similar methodological procedures, divided sequential epithelial changes into four categories: an inflammatory reaction, a phase of recovery, a secondary response, and eventually invasive carcinoma. They found pronounced atypia in a few epithelial cells during the inflammatory phase but none in the recovery phase. During the secondary response phase, they noticed two kinds of atypical nucleated epithelial cells. One type of cell stained bright red or orange and contained a large, clear nucleus with a large nucleolus