RESUMO
Abdominal actinomycosis is a rare finding in pediatric patients and its location in the urinary bladder is exceptional. On the other hand, immunodepression can be found in several disorders including that of actinomycosis. The purpose of this study was to report a case of urinary bladder actinomycosis seen in a seven year old girl. No risk factors were found. It was diagnosed as an abdominal tumor which was successfully surgically removed and treated with penicillin. During her recovery, she suffered from a transitory cell-mediated depression of her immune system which later returned to normal once treatment as installed. The pathogenesis of actinomycosis is presented and a review of the literature is cited. Actinomycosis; immunodepression; bladder.