[Disseminated nocardiosis presenting as retroperitoneal abscess: a case report].

A 64-year-old man presented to our emergency room with right back pain on July 10, 2009. At the emergency room, abdominal enhanced computed tomography revealed a cystic lesion in the retroperitoneum. Then he was referred to our department. We performed percutaneous drainage of the retroperitoneal lesion and aspirated white pus. The retroperitoneal cystic lesion proved to be an abscess. Microscopic examination of a Gram stained specimen of the abscess revealed gram-positive bacillary fragments ; therefore, we suspected the pathogen to be Nocardia. He had a history of chronic glomerulonephritis and had received treatment consisting of 20 mg prednisolone, and 75 mg cyclosporine per day. He was regularly visiting the department of cardiovascular for follow-up of chronic heart failure. On the day before his visit to our emergency room, his chest X-ray medicine had revealed a nodular shadow. Then he was referred to the department of respiratory medicine and was scheduled to receive a bronchoscopy later. We suspected the nodule of the lung also to be an abscess of Nocardia. Later, head computed tomography (CT) revealed a brain abscess the pathogen of which was Nocardia. Nocardia is a filamentous, gram-positive, branched bacterium and classified as an aerobic actinobacteria. Nocardia species are difficult to diagnose due to non-specific clinical and histological manifestation. We report this case of disseminated nocardiosis presenting as retroperitoneal abscess. The disseminated nocardiosis was diagnosed without delay by percutaneous drainage and appropriate treatment was provided.