Basaloid-squamous carcinoma of the esophagus with marked deposition of basement membrane substance.

A 71-year-old Japanese man with basaloid-squamous carcinoma of the esophagus is reported. The carcinoma contained basaloid cells, a few small cornified foci, and a large amount of eosinophilic hyaline substance, which reacted positively upon periodic acid-Schiff, type IV collagen, and laminin staining. Ultrastructural examination revealed markedly replicated basement membranes (BM). The morphological findings suggested that this tumor secreted abundant BM substance. Small nests of cancer cells were attached to the dysplastic esophageal epithelium. The tumor cells exhibited negative staining for mucin, secretory component, lactoferrin, and carcinoembryonic antigen. These findings, as well as the observed keratinization and attachment between the carcinoma nests and mucosal epithelium, indicate that the tumor originated in the mucosal epithelium of the esophagus.