Mucinous colorectal carcinoma: immunopathology and prognosis.

A total of 519 colorectal carcinomas were examined for the presence or absence of mucinous differentiation by means of microscopical morphometry. Of these, 28% had objectively measurable amounts of mucinous tumour epithelium. Tumours with > 50% mucinous areas (14%) had significantly poorer prognosis than non-mucinous in stages A and C, while mucinous differentiation did not correlate with prognosis in stages B and D. Lymph nodes regional to mucinous tumours had significantly less paracortical response, and those with < 50% mucinous differentiation, significantly less perivascular lymphocyte cuffing at the tumour margins. These lymph node and stromal compartments are putative T-lymphocyte areas, and hence our findings suggest that mucinous tumours are either less stimulatory or perhaps inhibitory of cell-mediated immunity.