Accessory Cardiac Bronchus

Radiologic Findings Axial (Fig. 1A-1F) and coronal (Fig. 2A-C) chest CT (lung windows) demonstrates an anomalous blind-ending bronchus arising from the medial aspect of the lower right main stem bronchus and bronchus intermedius that courses towards the right pulmonary artery and mediastinum. Not the absence of surrounding hematoma, extraluminal air and or pneumomediastinum.     Diagnosis: Accessory Cardiac Bronchus

Differential Diagnosis

None

Discussion

Variations of bronchial branching are common and may affect any portion of the tracheobronchial tree. These variations and are usually discovered incidentally. Right-sided anomalous bronchi are classified as pre-eparterial or post-eparterial if they arise proximal or distal to the origin of the right upper lobe bronchus respectively. Left-sided anomalous bronchi are classified as pre-hyparterial and post-hyparterial if they arise proximal or distal to the left upper lobe bronchus respectively. Upper lobe anomalous bronchi are much more common on the right than on the left. Displaced and supernumerary or coexistent normal upper lobe anomalous bronchi may also occur. Accessory cardiac bronchus is an anomalous bronchus that arises from the medial aspect of the right main stem or bronchus intermedius and courses towards the mediastinum. It is typically blind-ending but may be surrounded by lung parenchyma.

Clinical Findings

Most individuals with anomalous bronchi are asymptomatic and are diagnosed incidentally on chest CT. However, cases of hemoptysis and recurrent infection have been reported in association with anomalous bronchi.

Imaging Findings

Chest Radiography

• Most often normal

MDCT

• Visualization of anomalous bronchus emanating off the tracheal air column or proximal lobar bronchi  (Fig. 1A-F; 2A-C)
• Multiplanar reformations, shaded surface displays, volume rendering and virtual bronchoscopy techniques useful in anatomic characterization and classification

Treatment

• Usually not indicated
• Surgical resection in cases of recurrent infection or hemoptysis

Selected Readings

1. Berrocal T, Madrid C, Novo S, et al. Congenital Anomalies of the Tracheobronchial Tree, Lung and Mediastinum: Embryology, Radiology and Pathology. RadioGraphics 2004; 24 (1) e17.
2. Ghaye B, Szapiro D, Fanchamps J-M, et al. Congenital Bronchial Abnormalities Revisited. RadioGraphics 2001; 21: 105-109.
3. Parker MS, Rosado de-Christenson, Abbott GF. Tracheobronchial Anomalies. In: Teaching Atlas of Chest Imaging 2006; Thieme, New York; 35-38.