HISTOCHEMISTRY OF MUCIN SECRETING COMPONENTS IN MUCOEPIDERMOID AND ADENOSQUAMOUS CARCINOMA OF THE ESOPHAGUS

Aims-To determine the direction of differentiation of the mucin secret ing components in a rare group of oesophageal tumours-oesophageal squa mous cell carcinomas with prominent mucin secreting components (mucoep idermoid carcinomas and adenosquamous carcinomas). Methods-In a review of 617 cases of primary carcinoma of the oesophagus, 16 cases of squa mous cell carcinoma with prominent mucin secreting components were stu died using a battery of histochemical techniques. Results-The mucin pr oduced by these tumours was mixed and included a variable content of e nzyme labile sialomucin (positive for mucicarmine, periodic acid Schif f, and alcian blue, and sensitive to sialidase digestion and negative for high iron diamine-alcian blue). Retrospective analysis of endoscop ic biopsy specimens taken from these tumours showed that mucin was pre sent in five (42%) cases. Conclusions-The glandular component of this group of tumours histochemically differentiated in the direction of oe sophageal glands: examination of the mucin secreting component in squa mous cell carcinoma in resected specimens is therefore required for re cording the true incidence of this type of tumour.