Prevalence of oesophageal epidermoid metaplasia in 1048 consecutive patients and 58 patients with squamous neoplasms.

Aims Oesophageal epidermoid metaplasia is defined by a dense granular layer with overlying hyperorthokeratosis, resembling the epidermis of skin. A possible association between epidermoid metaplasia, squamous dysplasia and squamous cell carcinoma has been proposed. The aim of this study was to compare the prevalence of epidermoid metaplasia in patients with oesophageal squamous neoplasms with that in a control cohort. Methods and results Medical records and slides from 1048 consecutive oesophageal biopsies and resections for any indication and 58 patients with oesophageal squamous neoplasms were reviewed. Two cases (0.19%) of epidermoid metaplasia were identified in the 1048-patient control group. The prevalence of epidermoid metaplasia was significantly higher (P < 0.05) in the 58 patients with oesophageal squamous neoplasms, two of whom (3.5%) had concurrent epidermoid metaplasia (odds ratio 18.1, 95% confidence interval 2.5–131). One case was associated with a verrucous carcinoma and the other with a well-differentiated, superficial (pT1), exophytic squamous cell carcinoma. No patients had epidermoid metaplasia in a biopsy prior to the diagnosis of squamous neoplasia. Conclusions The increased prevalence of epidermoid metaplasia observed in patients with squamous neoplasms provides some additional support for the proposed association. The hypothesis that epidermoid metaplasia is a precursor to squamous neoplasms remains unproven.