Prognostic significance of periodic acid-Schiff-positive patterns in primary breast cancer and its lymph node metastases.

Invasive ductal carcinoma is by far the largest histological subtype of breast cancer, but clinical behavior can differ greatly. Reliable morphological markers are, therefore, of invaluable help to distinguish between patients with good and poor prognosis. Histological patterns stained with periodic acid-Schiff (PAS) were previously shown to be of prognostic significance in cutaneous and uveal melanoma. In this study, we examined the presence of different PAS-positive (PAS+) structures in 54 women with infiltrating ductal adenocarcinoma of the breast and at least one axillary lymph node metastasis but no distant metastases who were followed for at least 11 years. We found that the complexity of the thin PAS+ patterns in lymph node metastases is associated with a shorter period of disease free survival (DFS) as well as of total survival (Kaplan-Meier curves). Furthermore, the presence of PAS+ networks - the most complex thin PAS+ pattern - in lymph node metastases is one of the two independent factors associated with the occurrence of a distant metastasis (multivariate Cox model). Moreover, the presence of PAS+ networks in positive lymph nodes is the feature most strongly associated with DFS. In conclusion, the presence of PAS+ networks in lymph node metastases is a new, reliable and convenient indicator for prognosis of breast cancer patients.