The impact of schistosomiasis on the pathology of bladder carcinoma.

In a series of 1095 Egyptian patients with carcinoma of the bladder treated by radical cystectomy, 902 cases (82.4%) contained schistosome eggs in the specimens, and 193 (17.6%) were egg-negative. The different tumor parameters were compared in these subgroups to explore any differences that could be related to schistosomal infestation. In egg-positive cases, the tumor developed at a younger age (46.7 years) than in egg-negative cases (53.2 years). Squamous cell carcinoma, commonly of low grade, predominated in the egg-positive group. No difference was observed in the frequency of tumor stages or lymph node metastases between the two subgroups. The limited tendency to distant spread in schistosomal bladder cancer, despite its advanced local stage, is accounted for by the high frequency of low grade tumors rather than the limiting effect of local schistosomal tissue reactions.