Urinothorax: presentation of a new case as pleural exudate.

Urinothorax or urothorax (UT) is a rare condition which often goes undiagnosed. In published cases of UT, the pleural fluid is usually transudative and is very rarely exudative. We present a case of UT after right nephroureterectomy for urothelial carcinoma, in which the pleural fluid presented characteristics of exudate. The diagnosis of UT was confirmed with the finding of a pleural/serum creatinine ratio above one and after demonstrating the presence of a postsurgical urinoma in the right renal fossa. UT should be included in the differential diagnosis of pleural effusion in patients with a recent urinary tract disorder, even when it is pleural exudate.