Pleuritis clinically diagnosed as Aspergillosis during the course of microscopic polyangiitis

Pleural aspergillosis is a rare fungal infection. We herein report a case of pleuritis clinically diagnosed as aspergillosis without apparent Aspergillus lung lesions. A 75-year-old man receiving immunosuppressive therapy due to microscopic polyangiitis was admitted for treatment of massive pleural effusion. Histology of the parietal pleura revealed septate hyphae. In addition, a hematological marker of Aspergillus indicated Aspergillus pleuritis. The pleural effusion resolved after administration of the voriconazole. The trigger for invasion of Aspergillus into the pleura was thought to be spontaneous pneumothorax, which had occurred five months earlier.