Antenatally Detected Congenital Pulmonary Airway Malformations: The Oxford Experience

Abstract

Congenital airway pulmonary malformations are increasingly being diagnosed, but their management continues to remain controversial. Our approach has been to offer surgery to mitigate the risk of infection and possible malignancy. All patients routinely undergo a CT scan of the chest postnatally and once the diagnosis is confirmed, minimal access surgery is offered. Our anesthetists provide single-lung ventilation to enhance the operative view. We conducted a retrospective review over a 10-year period, during which 91 patients were prenatally suspected to have a cystic lung lesion. There were 88 live births of which 29 (33%) cases were initially managed conservatively based on CT findings. Five of these patients, however, became symptomatic needing surgery. A total of 64 (73%) patients underwent surgery with the most common lesions being congenital pulmonary airway malformations (CPAMs) (24), hybrid lesions (19), and pulmonary sequestrations (12). The median age at surgery was 5 months (1 day to 17 months). Using a minimal access approach, 41 (64%) cases were completed with 17 performed open from the onset. Open surgery was indicated in neonates who became symptomatic within the first few weeks of life as well as patients in respiratory distress that would not tolerate either single-lung ventilation or gas insufflation. There were six further conversions to open from minimal access surgery due to poor visualization or technical difficulties. One patient needed a perioperative blood transfusion and one patient had a more prolonged stay due to persistent air leak managed conservatively. Among asymptomatic patients, evidence of microscopic disease was seen, which included infection as well as two cases of tumors, one pleuropulmonary blastoma seen as part of a CPAM, and one rhabdomyomatous dysplasia seen in the CPAM component of a hybrid lesion. In our experience, excising asymptomatic lesions is safe with minimal complications. Single-lung ventilation in combination with thoracoscopy provides excellent vision. There is a risk of infection and a definite, albeit low, risk of malignancy, which may outweigh the benefits of conservative management.

Proximity to the Diaphragm Predicts the Presence of Rhabdomyomatous Dysplasia in Congenital Pulmonary Airway Malformations

“…[11][12][13][14] Various types have been described, including bronchoalveolar carcinoma, 14 rhabdomyosarcoma 15 and PPB. 9,10,18 The current understanding is that PPBs do not develop within what was thought to be a CPAM (as witnessed by a solid mass where once there was only a multi-cystic lesion), but were malignant all along: the cystic variant of PPBs, which by diagnostic imaging resembles a cystic CPAM, is typically found in younger children, suggesting that PPB is a slow-growing tumor that becomes increasingly solid and cellular. 9,10 Rhabdomyosarcoma, which had been reported in CPAMs, 15,27 is now believed not to occur in association with congenital lung lesions.…”

“…In a 2005 case report, Pai et al 16 identified a rhabdomyosarcoma in a CPAM, but corrected their assessment in 2007, calling the lesion a PPB. 17 Rhabdomyosarcoma can also be over-diagnosed when confused with RD, 18,27 which is a benign finding, and a not uncommon histological feature of CPAMs. The true significance and origin of these striated muscle elements has been unclear.…”

“…17 Moreover, rhabdomyomatous dysplasia (RD), a recognized (but unexplained) benign feature of some CPAMs, may be mistaken for a malignant tumor. 18 With the recent finding of RD in intradiaphragmatic CPAMs-fetal lesions that are located within the diaphragm 19-22 -we hypothesized that these smooth muscle elements might be derived from the diaphragmatic muscle and might therefore be more often associated with peridiaphragmatic lesions.…”

Pleuropulmonary blastoma type I might arise in congenital pulmonary airway malformation type 4 by acquiring a Dicer 1 mutation

“…The confusion between PPB I and CPAM 4 came from earlier reports. CPAM 4 has been described before the Stocker classification as CPAM associated with pleuropulmonary blastoma or rhabdomyosarcoma arising in CPAM [14,15]. Some authors have even raised the question if CPAM 4 exists [11,[23][24][25][26][27][28].…”

Malformación congénita de la vía aérea pulmonar

“…La precisión de la ecografía puede alcanzar 90 y 77% para sensibilidad y especificidad respectivamente. Su principal diagnóstico diferencial, el secuestro pulmonar, puede identificarse visualizando el origen del vaso nutricio viniendo directo de la aorta con la ecografía Doppler [4][5][6][7][8][9][10][11][12][13][14] .…”