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Arguments agains MR in CPAM

MR is better than US to distinguish btw BPS and CPAM, but both can cause hydrops and actual histology irrelevant if hydrops has occurred.


What is bronchopulmonary sequestration (BPS)?

A mass of nonfunctioning pulmonary tissue
Lacks an obvious connection with the tracheobronchial tree
Recieves all or most of its blood supply from anomalous systemic vessels


Is there a spectrum of BPS?

There appears to be - at one extreme, an abnl vessel supplying a nonsequestered lung, and at the other, abnl pulmonary tissue but w/o anomalous vascular supply


Can BPS and CCAM coexist in the same lesion?

Yes, it is referred to as a hybrid lesion. BPS and CCAM type II coexisting together has been reported in 25-50% of extralobar sequestration cases.


What are the forms of BPS?

2 forms:
Intralobar - more common in infants & children, accounting for 75% of cases, shares the same pleural investment with the normal lung.
Extralobar - 25% of cases in infants & children, has a separate pleura from the lung and may either be intrathoracic or subdiaphragmatic in location


Theory re: embryogenesis of BPS

A supernumerary lung bud arises caudal to the normal lung bud and migrates caudally with the esophagus. If this lung bud arises prior to pleural development, the bud becomes intralobar and is invested with adjacent lung. If arises after pleura formation, the bud will grow separately and become invested with its own pleura - extralobar BPS.


Male or female preponderance in BPS?

Male - Extralobar 3:1, intralobar 1.5:1


Which is more common in the fetus/neonate: extralobar or intralobar BPS?



Most common location of intralobar BPS?

Lower lobe in 98% of cases.


Most common location of extralobar BPS?

Posterior lower chest, 90% on left side.
Up to 15% of extraloabr BPS can be found either within or below diaphragm.


US findings of BPS

Solid, highly echogenic mass with a clearly defined systemic feeding vessel.
Occasionally, these vessels cannot be seen on US, making it difficult to distinguish from Type III CCAM.
Addl findings:
Pleural effusion
Mediastinal shift


Can intra vs extralobar BPS be distinguished on prenatal US?

Not usually. But several cases of extralobar BPS have been dx'd bc of finding of echogenic suprarenal abdominal masses.


How can extralobar BPS cause hydrops? BPS in general?

May undergo torsion of its vascular pedicle, causing venous and lymphatic obstruction, leading to pleural effusion and hydrops due to systemic venous obstruction.
BPS can cause compression of IVC with venous obstruction and compromised cardiac output. Poly may result from esophageal obstruction or decreased swallowing.


Prognosis of BPS with hydrops

Uniformly results in fetal or neonatal death if untreated. There are anecdotal reports of cases treated in utero with thoracoamniotic shunting of the pleural effusion.


Is there an increased risk of anomalies with BPS?

Yes, especially extralobar (60%). Most common = CDH, pectus excavatum, TE fistula, esophageal duplication, and congenital heart disease.
Intralobar type has a lower incidence of associated anomalies (10%).


DDx of intrathoracic BPS

Mediastinal or thoracic teratoma


DDx of intra-abdominal extralobar BPS

Mesoblastic nephroma


Antenatal natural history of BPS

Depends on if its intralobar or extralobar, thoracic or abdominal, presence of absence of hydrops and other associated anomalies. It was once thought that in fetuses with BPS, hydrops invariably developed, and fetus died in utero or during the neonatal period. Then 6 cases reported of BPS with contralateral mediastinal shift that dramatically decreased in size over time and spontaneously resolved. Postnatally, the lesions could only be seen on CT or MRI. There were no signs of hydrops in any of these cases. Adzick et al then reported that 75% of BPS dx'd prenatally resolve spontaneously.


Outcome of intra-abdominal extralobar BPS

Somewhat better than that for intrathoracid lesions, rarely associated with hydrops. Poly may still develop due to esophageal or gastric compression.


Management of pregnancy with BPS

Exclude CDH, mediastinal teratoma, CCAM
Eval adrenal glands & kidneys to distinguish abdominal extralobar BPS from mesoblastic nephroma & neuroblastoma
Detailed US for assoc anomalies
Fetal MRI can help with ddx and identify feeding vessel
Fetal karyotype
Fetal echo


Options for fetal intervention in BPS

If tension hydrothorax from pleural effusion, then thoracoamniotic shunting is an option
If mediastinal shift and hydrops from mass, without pleural effusion, then fetal surgery for pulmonary resection could be considered, as with CCAM.


Treatment of the newborn with BPS

If large - deliver in a setting prepared to deal with pulm hypoplasia
If small - community setting may be appropriate
Examine for associated anomalies
If intraabdominal, usually no resp compromise and can have elective resection


Common locations of feeding vessels in BPS

20% subdiaphragmatic - more common with right-sided lesions
15% more than one vessel present


Why should postnatal resection of BPS be considered

Risk of infection, hemorrage, and malignant transformation, even if asx


Recurrence risk of BPS

No known genetic predisposition
One case of recurrence in male siblings reported


What is CCAM?

Congenital cystic adenomatoid malformation (aka congenital pulmonary airway malformation)
Multicystic mass of pulmonary tissue with a proliferation of bronchial structures
Theories - may represent a failure of maturation of bronchiolar structures at 5-6w gestation, or focal pulm dysplasia, or result of airway obstruction.


Is CCAM more common in males or females?

Slightly more common in males


Is CCAM more commonly unilobar or multilobar? Unilateral or bilateral?

Unilobar in 80-95% of cases, bilateral in fewer than 2%.


Does CCAM have a communication with the tracheobronchial tree?

Yes, unlike BPS. But the connection is minute and tortuous.


Where does the blood supply come from for CCAMs?

Arterial and venous drainage comes from nl pulmonary circulation, in contrast to BPS. Anomalous A/V drainage has been reported, as well as "hybrid" CCAMs that have a systemic blood supply.