Figure 4,5,6: Contrast enhanced CT chest 3D reconstructed images. Figure
4 shows origin of the feeding vessels from the descending thoracic aorta
(arrow). Figures 5 and 6 show the draining of the tortuous vessels in
the right apical pulmonary artery (arrow).
Discussion:
Bronchopulmonary arterial malformation (BPAM) is a rare congenital
anomaly that can present with a wide range of respiratory symptoms. The
exact incidence of congenital BPAM has not been reported in literature.
Some cases of acquired BPAM have also been reported in the literature
with causes ranging from infection to tuberculosis, pneumonia,
actinomycoses, tumor, and trauma (9). It is typically diagnosed in
childhood or adolescence, but an asymptomatic case presenting in
adulthood, like the one discussed here, is extremely rare. There were no
lung findings or history in our patient to suggest an acquired cause. In
this case, we discuss the diagnosis and pathophysiology of BPAM and the
dilemma in the treatment of an asymptomatic patient.
Bronchial-pulmonary arterial malformation (BPAM) or racemose hemangioma
of the bronchial artery is a rare congenital malformation of the
bronchial artery which is characterized by a dilated and convoluted
bronchial artery with vascular hyperplasia and anastomosis with adjacent
systemic vessels and fistulous communication with pulmonary artery (7).
Such a convoluted bronchial artery with pulmonary anastomosis has been
described in the literature since the late 1970s and termed angiomatoid
vascular convolution of the bronchial artery, racemose angioma of the
bronchial artery, bronchial angiomas (6,8). Since then, case reports of
malformation between systemic to pulmonary arteries has been reported in
the literature by various names like bronchial arteriovenous
malformation, bronchopulmonary arterial anastomosis, bronchopulmonary
shunt, bronchial artery-pulmonary artery malformation and fistula, and
racemose hemangioma of bronchial artery (1, 2).
The lungs have two separate vascular systems consisting of the pulmonary
and bronchial arteries. Pulmonary artery arises from the right heart and
is a low-pressure system where as bronchial artery arises from the aorta
(systemic circulation) and has approximately 6 times higher pressure
than the pulmonary circulation. Pulmonary arteries participate in gas
exchange at the alveolar level, while bronchial arteries provide
nourishment to the supporting structures of the lungs, including the
pulmonary arteries (2). Bronchial arteries are connected to the
pulmonary arteries through several microvascular anastomoses at the
level of the alveoli and respiratory bronchioles. This preexisting right
to left shunt is nonfunctional in the physiological state, however
significant flow can be noted in the disease state like pulmonary
embolism. This is one of the anatomical basis of bronchial to pulmonary
arterial shunt. (1).
Most of the patients with systemic to pulmonary AV malformations are
asymptomatic. Case reports of life-threatening hemoptysis due to the
condition have however been described. The condition is more commonly
seen in young male patients (3,4). Chest radiographs are often abnormal,
but lesions are usually nonspecific and minimal. Definitive diagnosis is
possible by CT angiography or conventional angiography.
Broncho-pulmonary arterial malformation is an extremely rare vascular
malformation, so treatment guidelines are less established. Treatment of
life-threatening hemoptysis have been reported with modalities like
lobectomy, trans-arterial embolization. However, the natural course of
the disease and the need for treatment in an asymptomatic patient is not
well established (5). Our patient was counseled about the incidentally
identified abnormality and given the option of treatment by embolization
and follow-up. He opted to be on routine clinical and radiological
follow-up.
Conclusion:
Broncho-pulmonary arterial vascular malformation is a rare entity and
has been reported in the literature with various names. The cases are
usually asymptomatic; however, they have the potential for
life-threatening hemoptysis.
Conflict of interest:
None
References :
1. James R. Yon, MD and James G. Ravenel M, Abstract: Congenital
Bronchial Artery-Pulmonary Artery Fistula in Adult. 2010;33(1):31–4.
2. Walker CM, Rosado-De-Christenson ML, Martínez-Jiménez S, Kunin JR,
Wible BC. Bronchial arteries: Anatomy, function, hypertrophy, and
anomalies. Radiographics. 2015;35(1):32–49.
3. Pouwels HM, Janevski BK, Penn OC, Sie HT, ten Velde GP. Systemic to
pulmonary vascular malformation. Eur Respir J. 1992;5:1288–91.
4. Soda H, Oka M, Kohno S, Watanabe M, Takatani H, Hara K. Arteriovenous
malformation of the bronchial artery showing endobronchial
protrusion. Intern Med. 1995;34:797–800.
5. Uchiyama D, Fujimoto K, Uchida M, Koganemaru M, Urae T, Hayabuchi N.
Bronchial arteriovenous malformation: MDCT angiography findings. AJR Am
J Roentgenol. 2007;188(5):409–11.
6. v Babo H, Huzly A, Deininger HK, Barth V. Angiome und angiomartige
Veränderungen der Bronchialarterie [Angiomas and angioma-like changes
of the bronchial arteries (author’s transl)]. Rofo. 1976
Feb;124(2):103-10. German. PMID: 131059.
7. Ito A, Takao M, Shimamoto A, Shimpo H. Primary racemose
hemangioma with bronchial-pulmonary arterial fistula. Respirol Case Rep.
2018 Apr 1;6(5):e00314. doi: 10.1002/rcr2.314. PMID: 29619221; PMCID:
PMC5879031.
8. Cain H, Spanel K. [Etiology and morphogenesis of the socalled
bronchial arterioma (author’s transl)]. Klinische Wochenschrift. 1980
Apr;58(7):347-357. DOI: 10.1007/bf01477277.
9. Yon JR, Ravenel JG. Congenital bronchial artery-pulmonary artery
fistula in an adult. J Comput Assist Tomogr. 2010;34:418–20.