Perinephric abscess: an unusual presentation of perforation of the colon.

Perinephric abscess caused by spread of infection from an adjacent extrarenal focus is rare. Prior to diagnosis, several features of this case suggested such a pathogenesis: absence of an associated upper urinary tract infection or a distant focus for hematogenous seeding, and late recurrence of the abscess despite prompt clinical response following drainage and antimicrobial therapy. Specifically, the large bowel was suspected early on and subsequently documented as the source of infection because of the unusual finding of a polymicrobial perinephric abscess.