Spindle cell squamous carcinoma of the oesophagus: an analysis of 17 cases, with new immunohistochemical evidence for a clonal origin

Aims: To study the morphological and immunohistochemical characteristics of spindle cell squamous carcinoma of the oesophagus, in order better to understand the histogenesis of this tumour. Methods and results: In this study we analysed the morphological and immunohistochemical characteristics of 17 cases of spindle cell squamous carcinoma of the oesophagus. Most tumours were polypoid, but tumours with an ulcerated and infiltrative pattern were also observed. Histologically, most tumours were of superficial type, with a characteristic morphological aspect consisting of two types of tumour cells, i.e. differentiated squamous cells, and spindle cells with transition zones between the two components. On immunohistochemistry, the squamous cells were positive for cytokeratin and the spindle cells showed variable expression of cytokeratin, vimentin and smooth muscle actin. p53 protein was over-expressed in 10 cases, both tumour cell types showing strong nuclear positivity. In most tumours, E-cadherin was expressed in the squamous cells and absent in the spindle cells. Conclusions: The similar pattern of p53 protein expression in the two tumour cell types of spindle cell squamous carcinoma of the oesophagus suggests their common origin. The change in adhesion molecule expression with loss of E-cadherin expression may be associated with the acquisition of spindle cell morphology by the squamous tumour cells.