Nephrogenic pleural effusion.

Although the presence of a pleural effusion is almost always indicative of an intrathoracic problem reflection will yield a certain number of extrathoracic causes, such as hypoproteinemia, Meigs' syndrome pancreatitis and subphrenic abscess. The kidney is a close neighbor of the diaphragm and pleural cavity, and a case of renal stone associated with a small ipsilateral pleural effusion, which regressed with resolution of the primary process, is reported.