Oesophageal cancer composed of mixed histological types.

Glandular or adenoid cystic differentiation and sarcomatous features are sometimes encountered in oesophageal cancer and such histological variants often coexist with ordinary squamous cell carcinoma. So far no serial evaluation of such mixed histological types of oesophageal cancer has ever been performed, we therefore clinicopathologically investigated such cases While an immunohistochemical study of the p53 protein was also done on four available cases in order to discuss the histogenesis of these tumours. Among the 600 patients with surgically resected oesophageal cancer, seven cases were found to have a mixture of histological variants with ordinary SCC (squamous cell carcinoma) (adenocarcinoma 1, adenoid cystic cancer 3, sarcomatous component 2, basaloid cystic cancer and sarcomatous component 1). All but one case had an elevated type tumour while the predominant components of protrusion were not SCC but variant histological types. Six tumours were restricted to the submucosal layer. An immunohistochemical study of the p53 protein revealed that two of four cases were positive in both the SCC and variant patterns. Mixed histological types of oesophageal cancer composed of SCC and other variants often occur and thus the carcinogenesis of both histological types are considered to be aspects of the same mechanism.