The histological spectrum of chronic necrotizing forms of pulmonary aspergillosis

Abstract

Chronic necrotizing pulmonary aspergillosis (CNPA) is a rare locally destructive form of chronic aspergillosis that is recognized as a clinical syndrome, but has been poorly defined histologically. In this study, 10 cases of CNPA were evaluated from a morphological perspective. Three distinct forms of CNPA emerged. One form (n = 4) resembled a necrotizing granulomatous pneumonia centered around a central zone of infarct-like necrosis of parenchyma resulting from angioinvasive aspergillus. The second pattern (n = 4) was that of a granulomatous bronchiectatic cavity with a central fungus ball and subtle tongues of necrosis and inflammation extending into and through the fibrous wall of the cavity. A final form (n = 2) had a bronchocentric granulomatosis-like appearance with a necrotizing granulomatous bronchitis/bronchiolitis associated with luminal necrotic debris and replacement of mucosa by a palisaded histiocytic reaction. Despite the varied histomorphology, all patients survived the aspergillus infection after antifungal therapy and surgical resection. The different forms of pulmonary aspergillosis are briefly discussed, and the differential diagnosis, with particular regard to mycetomas and allergic forms of bronchocentric granulomatosis, is highlighted.