Invasive aspergillosis is one of the commonest fungal infections in immunocompromised hosts, involving the respiratory tract in 90% of cases . This disease occurs almost exclusively in immunosuppressed patients, although there have been few reports in immunocompetent patients. Invasive pulmonary aspergillosis (IPA), the most common manifestation of Aspergillus spp. infection in immunocompromised patients, typically involves the lung parenchyma, rarely affecting the trachebronchial tree exclusively.
A 65 year-old male with history of chronic lymphocytic leukemia developed cough and malaise eight months after an allogenic stem cell transplant. A computed tomography of the chest revealed an area of diffuse soft tissue thickening around the left main stem bronchus, which was intensely fluorodeoxyglucose-avid on positron emission tomography scanning (PET)(figure 1). An initial bronchoscopic exam revealed circumferential narrowing of the entire left main stem bronchus with necrotic and friable material on the medial wall. Both aspirates from this necrotic area and bronchial washing were not diagnostic. A second bronchoscopy with convex-probe endobronchial ultrasound evidenced a soft tissue thickening on the medial aspect of the left main stem bronchus underlying the area of necrosis visible endoluminally (figure 2). Endobronchial ultrasound-guided transbronchial needle aspiration performed in this area revealed multiple fungal elements suggestive of Aspergillus spp.
Aspergillus fumigatus is the most common species responsible for invasive aspergillosis, followed by Aspergillus flavus, Aspergillus niger and Aspergillus terreus. Invasive aspergillus tracheobronchitis (IATB) is a rare manifestation defined as localized invasion of the bronchial wall by aspergillus. Young et al. reviewed the postmortem findings of 98 cases of aspergillosis finding the infection limited to the tracheobronchial tree in only five patients .Three morpholgical variants of IATB have been described: obstructive tracheobronchitis, ulcerative tracheobronchitis and pseudomembranous necrotizing bronchial aspergillosis. The ulcerative form,like the one we found in our patient, consists of lesions that penetrate through the tracheo-bronchial wall sometimes creating bronchoesophageal or bronchoarterial fistulas that may produce fatal hemorrhage. These three morphologic variants may indeed represent different stages in the development of invasive tracheobronchial aspergillosis.The insidious presentation of IATB with non-specific symptoms and the paucity of findings in chest roentgenograms often delay the diagnosis, giving this disease an ominous prognosis. There is little documentation of the radiologic features of IATB. We are presenting the first PET/CT scan images of IATB in the literature.The diagnosis of IATB is almost always confirmed by bronchoscopy. Aspiration of debris and bronchial washings allow the diagnosis in the majority of cases by showing the presence of aspergillus hyphae in special stains or recovering the organism in fungla cultures. To the best of our knowledge, this is the first case of IATB in which the diagnosis was facilitated by EBUS. It is our opinion that real-time EBUS might also be useful to delineate the depth of the tracheobronchial wall invasion and the involvement of major vascular structures, potentially preventing lethal hemorrhage.
In conclusion, IATB is a rare form of invasive aspergillosis affecting mainly immunocompromised patients. The non-specific clinical presentation often leads to late diagnosis and a poor prognosis. We are reporting the first case of IATB diagnosed by EBUS-guided TBNA. We also cautiously suggest that EBUS imaging may be a useful tool to evaluate the degree of invasion and the involvement of vascular structures in these patients prior to bronchoscopic manipulation of the affected areas.
Roberto Casal, No Financial Disclosure Information; No Product/Research Disclosure Information