Squamous cell carcinoma of the gallbladder associated with squamous metaplasia and adenocarcinoma in situ of the mucosal columnar epithelium.

A case of well-differentiated squamous cell carcinoma of the gallbladder is presented. Unlike most previously reported cases, the tumor developed in association with squamous metaplasia as well as dysplastic and in situ adenocarcinomatous changes of the gallbladder epithelium. The significance of these lesions is discussed in relation to the histogenesis of squamous cell carcinoma or adenosquamous carcinoma of this organ.