SCHWANN-CELL DIFFERENTIATION OF MODIFIED MYOEPITHELIAL CELLS WITHIN ADENOID CYSTIC CARCINOMAS AND POLYMORPHOUS LOW-GRADE ADENOCARCINOMAS - CLINICOPATHOLOGICAL ASSESSMENT OF IMMUNOHISTOCHEMICAL STAINING

Adenoid cystic carcinomas and polymorphous low-grade adenocarcinomas h ave a known propensity for perineural invasion. Although modified myoe pithelial cells have been shown to possess characteristics of a variet y of cell types, they have not yet been found to mimic nerve tissue. H istologic evidence of Schwann cell differentiation would suggest the p athophysiologic mechanism by which these tumours exhibit neurotropism. An archival study of 41 specimens was performed to evaluate the Schwa nn cell staining properties of adenoid cystic and polymorphous low-gra de adenocarcinomas using antibodies to S-100 protein, GFAP, neuron-spe cific enolase, and using a solochrome stain. Charts were reviewed to a ssess correlations between immunohistochemical and histochemical stain ing properties and various clinical parameters. The findings strongly suggest that neuronal differentiation does occur within these rumours. Furthermore, it was determined that solochrome positivity confers a s ignificantly less favourable disease-free interval in these neoplasms. This new finding was highly statistically significant and has potenti al implications in the determination of prognosis for patients with th ese tumours.