The aim of the present study was to describe changes which could be regarded as a result of neoplastic rather than inflammatory processes. Fifty‐five weeks after 6 weeks of DMBA application to the cheek pouches of 5 male hamsters there were 4 types of lesion: larger ulcerated sessile: smaller non‐ulcerated sessile: non‐ulcerated pedunculated; conical projections. These and the rest of the pouches were examined by scanning electron and light microscopy. The interlesional mucosa, non‐ulcerated sessile lesions and conical projections were covered by flat polygonal cells with either a honeycomb surface pattern of interconnecting microridges, or microridges arranged into more parallel lines. Cell imprints and boundaries were formed by linear ridges, grooves or both. Pedunculated lesions had flat smooth‐surfaced cells and cells with a honeycomb surface pattern. None of these lesions were carcinomas by light microscopy but the ulcerated sessile lesions were. The appearance of the cells on the ulcerated lesions varied: flat, with a variable number of short microvilli that were often knob‐like, isolated short microridges, or both: plump, giving a cobblestone appearance with surfaces that were smooth, covered by microvilli, short microridges or both. Such appearances have been described as characteristic for dysplastic and malignant stratified squamous epithelium in a number of sites. Further study of both experimental and naturally occurring mucosal disease is needed to va