Clinicopathological characteristics of esophageal squamous papillomas in Japanese patients--with comparison of findings from Western countries

Abstract

To clarify the characteristics of esophageal squamous papillomas (ESPs) in the Japanese population, we investigated 38 ESPs of 35 Japanese patients from a file with 17,387 upper gastrointestinal endoscopies in our university hospital. ESPs accounted for 0.20% of the total number of endoscopies and comprised 21 females and 14 males with an average age of 59.2 years. More than half of the ESPs (52.6%) were located in the middle esophagus. The ratio of human papilloma virus (HPV) positive ESPs was 10.5% and all were located in the middle esophagus of female patients only. HPV-positive ESP cases were younger (46.8 years) than HPV-negative cases (60.8 years). Based on comparison with the reports from western countries, we attribute the low prevalence in the lower esophagus to the relatively fewer occurrences of severe reflux esophagitis (RE) due to chronic gastritis with low gastric acid secretion among Japanese patients.

Fig. 1

Histological findings of esophageal squamous papilloma. a) Representative histological features of ESP. The ESP shows a papillary projection lined with acanthotic squamous epithelium (original magnification: ×10). b) Marked neutrophil infiltration in the whole tumor epithelium (original magnification: ×25). c) Koilocytosis in ESP is vague compared with dysplasias of uterine cervix (original magnification: ×25).

Fig. 2

Correlation of tumor location with neutrophil infiltration in the tumor epithelium (p<0.003).

Fig. 3

Representative findings of MIB-1 immunohistochemical stains of esophageal squamous papillomas (original magnification: ×10). a) A papilloma case with low MIB-1 index. b) A papilloma with high MIB-1 index.

Fig. 4

Results of PCR analysis to detect human papilloma virus (HPV) infection in ESPs. a) PCR products using consensus primers-PCR. Lanes 1-4: PCR products from four cases are HPV-positive. Lane 5, negative control (no DNA); Lanes 6, positive control (synthetic DNA). b) PCR products digested by restriction enzyme Afa I. Lanes 1–4 indicate HPV subtype 6.