Citation, DOI & article data
This anomaly is rare and is reported in ~0.3% (range 0.09-0.5%) of individuals 3-5. There may be a predilection for males.
The vast majority of cardiac bronchi are asymptomatic. In some patients with lung parenchyma supplied by this bronchus, abnormal drainage predisposes to repeated chest infection 2. Hemoptysis 4 as well as cases of malignant transformation 6-9 have also been described.
The anomaly is thought to occur between the 4th and 6th weeks of gestation, during development of the bronchial tree 3.
The histology of its wall is that of normal airway.
A cardiac bronchus arises from the bronchus intermedius, opposite and just distal to the origin of the right upper lobe bronchus. It is variable in size, morphology and length (range from 0.5-5 cm) 1,3. In about half of cases, the cardiac bronchus is a short blind-ending bronchial stump with no branches and does not supply any lung parenchyma. In the remainder, the bronchus may have branches and an amount of aerated lung parenchyma 1.
It is the only recognized true supernumerary bronchus, with other anomalies representing aplasia or abnormal branching patterns 3.
A cardiac bronchus is almost always an incidental finding of CT examination of the chest. It appears as a continuation of the lumen of the bronchus intermedius, projecting medially and directly inferiorly towards the posterior aspect of the heart in a caudal direction.
In some cases, the dependent lung parenchyma may be collapsed and mimic a soft tissue mass 2.
Treatment and prognosis
As these structures are usually asymptomatic, no treatment is required. In rare instances where recurrent infections can be attributed to a cardiac bronchus then surgical resection may be carried out 3.
History and etymology
It is thought to be first described by RC Brock in 1946 11.
There is usually little, if any, differential diagnosis as most cases are classical in appearance. In atypical cases, differential includes:
- different histologically: diverticula do not have normal bronchial wall morphology
bronchial laceration in trauma
- almost always associated with other chest traumatic injuries
- necrotic/cavitating mass
- a consideration when associated lung parenchyma is atelectatic
- owing to the possible complications mentioned above, the role of the radiologist is to both identify and report this rare anomaly
- bronchoscopy may be indicated to differentiate the entity from a diverticulum 9
- 1. Shields TW. General Thoracic Surgery. Lippincott Williams & Wilkins. (2009) ISBN:0781779820. Read it at Google Books - Find it at Amazon
- 2. Parker MS, Christenson ML, Abbott GF. Teaching atlas of chest imaging. (2006) ISBN:3131390212. Read it at Google Books - Find it at Amazon
- 3. Mcguinness G, Naidich DP, Garay SM et-al. Accessory cardiac bronchus: CT features and clinical significance. Radiology. 1993;189 (2): 563-6. Radiology (abstract) - Pubmed citation
- 4. Keane MP, Meaney JF, Kazerooni EA et-al. Accessory cardiac bronchus presenting with haemoptysis. Thorax. 1997;52 (5): 490-1. Thorax (link) - Free text at pubmed - Pubmed citation
- 5. Müller NL, Silva CI. Imaging of the chest. (2008) ISBN:141604048X. Read it at Google Books - Find it at Amazon
- 6. Cho JH, Lee SH, Kim KT et-al. Surgical resection of adenocarcinoma arising from an accessory cardiac bronchus. Ann. Thorac. Surg. 2012;94 (3): 1006-8. doi:10.1016/j.athoracsur.2012.01.079 - Pubmed citation
- 7. Miyahara R, Hasegawa S, Yoshimura T et-al. A case of squamous cell carcinoma arising from accessory cardiac bronchus. Eur J Cardiothorac Surg. 2002;22 (2): 309. Pubmed citation
- 8. Leo F, Galetta D, Borri A et-al. Segmentectomy for carcinoid arising from an accessory cardiac bronchus. Eur J Cardiothorac Surg. 2009;35 (3): 537. doi:10.1016/j.ejcts.2008.12.015 - Pubmed citation
- 9. Barreiro TJ, Gemmel D. Accessory cardiac bronchus. Lung. 2014;192 (5): 821-2. doi:10.1007/s00408-014-9617-2 - Pubmed citation
- 10. https://doi.org/10.1016/S0003-4975(99)01200-X - to be linked on citeitright
- 11. https://pubs.rsna.org/doi/full/10.1148/rg.2016150115 - to be linked o citeright
- 12. https://doi.org/10.1016/S1010-7940(02)00431-1 - to be linked on citeright