Histological suggestions of ‘paratransformation’ in oesophageal squamous cell carcinoma

We have postulated that oesophageal squamous cell carcinoma arises from multifocal areas and not from one cell, and we present the circumstantial evidence for field carcinogenesis in oesophageal cancer. Among 290 cases examined with oesophageal squamous cell carcinoma, lymphatic permeation or intramural metastasis was evident in 110 cases. Of these carcinomatous transformation of the epithelium adjacent to either lymphatic vessel permeation or intramural metastasis of the squamous cell carcinoma was recognized in six cases. It is considered that the cancer tissue either in the lymphatic vessel or intramural metastasis promotes a malignant transformation of the squamous epithelium over these foci. ‘Paratransformation’ is therefore thought to be one of the potential models of origin for oesophageal squamous cell carcinoma.