The relationships between the histologic feature of mucin leakage into the cervical stroma, lymph node metastasis, and the levels of serum carcinoembryonic antigen (CEA), CA 19-9, and CA 125 were analyzed in 35 cases of cervical adenocarcinoma. Histologically, mucin leakage was identified in 14 (40%) cases as amorphorous materials dissecting the connective tissues and permeating the lymphatic channels, associated with or without cancer cells. The cases with mucin leakage showed a significantly higher incidence of lymph node involvement than those without mucin leakage (71.4% versus 23.8%; P less than 0.01). In addition, when the mucin leakage was immunohistochemically positive for CEA or CA 19-9, elevated serum levels of these antigens were frequently observed. These results suggest that the mucin leakage into the cervical stroma represents not only stromal invasion, but also a means that frequently conducts cancer cells into the lymphatic channels. Clinically, this is reflected in an elevation of serum CEA or CA 19-9 levels in cervical adenocarcinoma patients.