We have previously analyzed the expression of MUC1, underglycosylated MUC1, MUC2, MUC5AC, Tn, sialyl Tn, Lewis(a), sialyl Lewis(a), Lewis(x), and sialyl Lewis(x) in papillary thyroid carcinoma (PTC). The present study of 26 thoroughly scrutinized cases of PTC with "good " or "bad outcome" and a minimum of 10 yr of follow-up (or until death of the patients) was undertaken in an attempt to find if there is any relationship between the expression of the aforementioned antigens and the clinicopathologic and morphologic features of the cases and to evaluate the prognostic significance of the immunohistochemical pattern of PTC. We observed a significant or suggestive association between the expression of MUC1, underglycosylated MUC1, MUC2, Lewis(a), and Lewis(x) and the older age of the patients, and a suggestive association between Lewis(x) expression and lymph node metastasis and venous invasion. There was also a strong correlation between extrathyroid invasion, lymph node metastasis, intrathyroid dissemination, and venous invasion and patients outcome thus demonstrating, once more, the prominence of the classic clinicopathologic and morphologic features in the prognostic evaluation of PTC. The immunohistochemical study of mucins, simple mucin antigens, and histo-blood group antigens did not provide additional prognostic information, but for the significant association of Lewis(x) immunoreactivity to the group of "bad outcome."