Chronic esophagitis evolving to verrucous squamous cell carcinoma: possible role of exogenous chemical carcinogens.

Background & Aims: A patient exposed to aerosolized lye and ingested kerosene was followed up for 16 years with chronic esophagitis before developing verrucous esophageal squamous carcinoma. The aim of this study was to elucidate the pathogenesis of the carcinoma.

Methods: Multiple biopsy specimens were graded according to the severity of esophagitis and dysplasia. Molecular biological techniques and immunocytological assay were used to look for human papillomavirus infection, p53 mutations, loss of heterozygosity for TP53 and chromosome 8 markers, and ras mutations.

Results: Morphological features of the chronic esophagitis in this patient were similar to the precancerous lesions from high-risk areas for esophageal squamous cancer and the precancerous lesions induced in rats by N-methyl-N-nitrosoaniline. Gastroesophageal acid reflux and human papillomavirus infection were ruled out. No loss of heterozygosity of p53 or for chromosome 8 markers was found. Mutations of the ras oncogene were not identified. By immunocytological assay overexpression of p53 was identified only in the invasive portion of the carcinoma.

Conclusions: In this patient, verrucous squamous carcinoma evolved from chronic esophagitis, squamous papillary hyperplasia, and dysplasia. Although exogenous carcinogens may have been important, they probably did not act by causing loss of heterozygosity or ras mutations. p53 overexpression occurred late.