Uninvited guest, Balantidium coli in urine in a patient with bladder cancer: A case report and review of the literature.

Key Clinical Message: In contrast to intestinal balantidiasis, which is widespread throughout the world, urinary balantidiasis is uncommon. It often affects people with underlying diseases, and acute infections may be fatal. Even though urine is not typical for this parasite, specific morphologic characteristics can aid in accurate diagnosis. Abstract: Balantidium coli is a ciliated protozoan which can infect intestinal system. Urinary balantidiasis is an extremely rare infection that may cause serious issues in patients with underlying diseases. Herein, we present a case of urinary balantidiasis in a patient with bladder cancer.