Hepatic cyst infection in an autosomal dominant polycystic kidney disease patient diagnosed by right pleural effusion

A 64-year-old Japanese man with renal dysfunction caused by autosomal dominant polycystic kidney disease (ADPKD) was admitted to our hospital for evaluation of right back pain, fever, inflammation, and pleural effusion. Diagnostic investigations for tuberculous pleuritis were all negative. Although no radiographic abnormality suggesting hepatic cyst infection was detected by computed tomography, hepatic cyst drainage demonstrated purulent contents indicative of cyst infection. Conglutination of the cyst by minocycline 100 mg was performed five times in addition to drainage. After drainage, the symptoms of inflammation, right back pain and right pleural effusion subsided. Renal function and anemia, which had been resistant to darbepoetin treatment, also improved after the procedure. These results suggested that the infected hepatic cyst was associated with the patient's symptoms, exacerbation of renal dysfunction and anemia. The pleural effusion was due to the propagation of inflammation from the cyst infection. This is the first report of an infected hepatic cyst in an ADPKD patient presenting with and diagnosed by right pleural effusion.