대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Invasive aspergillus tracheobronchitis

Radiologic Findings

On chest CT scan performed at local medical center 1 month ago, soft tissue density mass with lobar bronchial obstruction was noted at right upper lobar bronchus.
On CT scan, previously seen soft tissue density mass was increased in size and extension into right main bronchus was seen. Atelectatic change of right lower lobe was also noted.
Bronchoscopy with biopsy was performed. Right main bronchus was nearly obstructed by polypoid necrotic mass with fibrin materials. GMS stain reveals many fungal organisms(not shown).

Brief Review

Invasive aspergillosis is one of the most common fungal infections in immunocompromised hosts, involving the respiratory tract in 90% of cases. The most common form of aspergillus species infection in immunocompromised patients is invasive pulmonary aspergillosis, which mainly involves the lung parenchyma and, rarely, the trachebronchial tree. Infection confined only to the tracheobronchial tree is known as invasive aspergillus tracheobronchitis (IATB), and it generally carries an ominous prognosis(1).
Three morpholgical variants of IATB have been described:obstructive tracheobronchitis, ulcerative tracheobronchitis and pseudomembranous necrotizing bronchial aspergillosis (PNBA) [6,8,9]. The obstructive form is characterized by massive intraluminal growth of aspergillus
species associated with thick mucus plugs that generally produce atelectasis. Ulcerative lesions penetrate through the tracheo-bronchial wall, and can create bronchoesophageal or bronchoarterial fistulas that may produce fatal hemorrhage. PNBA is characterized by extensive formation of whitish pseudomembranes composed of hyphae, fibrin and necrotic debris. Rather than three distinct entities, these morphologic variants may just represent different stages in the development of IATB.
Huang et al(2) classifed iIATB into four different forms according to the bronchoscopic features of intraluminal lesions: superficial infiltration type(Type I), full-layer involvement type (Type II), occlusion type (Type III) and mixed type (Type IV). Type IV was the largest group in this study, followed by Type III. All patients with iIATB of Type IV had definite airway occlusion.
The clinical mainfestations of IATB are entirely different from those of invasive pulmonary aspergillosis. The insidious presentation with non-specific symptoms and the paucity of findings in chest roentgenograms often delay the diagnosis, giving this disease an ominous prognosis. Airway-related symptoms such as cough, dyspnea, wheezing and hemoptysis are cardinal features.
The diagnosis of IATB is almost always confirmed by bronchoscopic examination and sampling.
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 poor prognosis.

References

1. Casal RF, Adachi R, Jimenez CA, Sarkiss M, Morice RC, Eapen GA. Diagnosis of invasive aspergillus tracheobronchitis facilitated by endobronchial ultrasound-guided transbronchial needle aspiration: a case report. J Med Case Reports. 2009 Nov 23;3:9290
2. Wu N, Huang Y, Li Q, Bai C, Huang HD, Yao XP. Isolated invasive Aspergillus tracheobronchitis: a clinical study of 19 cases. Clin Microbiol Infect. 2010 Jun;16(6):689-95. Epub 2009 Aug 18

Keywords

bronchus, infection, Fungal infection,