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 Table of Contents  
Year : 2023  |  Volume : 3  |  Issue : 3  |  Page : 154-157

Resolution of Fetal hydrops-not a favorable outcome in congenital pulmonary malformation type 1: A case report with review of literature

1 Department of Pediatric Surgery, Ca' Foncello Hospital, Treviso, Italy
2 Department of Obstetrics and Gynecology, Ca' Foncello Hospital, Treviso, Italy
3 Department of Pathology, Ca' Foncello Hospital, Treviso, Italy

Date of Submission23-Oct-2022
Date of Decision15-Jun-2023
Date of Acceptance29-Jun-2023
Date of Web Publication14-Aug-2023

Correspondence Address:
Dr. Dalia Gobbi
Piazzale Ospedale 1, Treviso 31100
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ipcares.ipcares_252_22

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Background: Congenital pulmonary airway malformations (CPAMs) comprise a spectrum of anatomical anomalies of the lungs and respiratory tree. The natural history of prenatally diagnosed CPAM varies from in utero resolution to progression to hydrops and intrauterine death. The majority of fetuses (90%) have a good outcome. However, in a minority (10%), the mass may grow so large that it is associated with complications and becomes life-threatening to the fetus. Clinical Description: Prenatal diagnosis of giant left CPAM type 1 was made at 24 weeks of gestation in a 29-year-old primigravida woman. The lesion consisted of multiple large cysts with a CPAM volume ratio of 4.7. Since the diagnosis, the mass was associated with nonimmune fetal hydrops and polyhydramnios which got worse throughout the following 4 weeks of gestation. Doppler studies remained normal until term. Management: The family received prenatal counseling. Parents refused termination of pregnancy and any other invasive or pharmacological therapy in light of the bad prognosis. The pregnancy was strictly monitored using standard fetal lung parameters. By 31 weeks' gestation, hydrops spontaneously improved to resolution but without any change in the size of the cysts. A baby girl was delivered at term, with birth asphyxia, who, despite all efforts by a multidisciplinary team, could not be revived. Autopsy and histopathological findings were compatible with type 1 CPAM. Conclusion: Hydrops is a well-known complication in fetuses with congenital cystic adenomatoid malformation. The present case reminds the possibility of its spontaneous resolution during pregnancy, even though the cyst size remains unaltered. The eventual neonatal survival depends not on the presence of hydrops but on the cyst volume and underlying lung hypoplasia.

Keywords: Congenital cystic adenomatoid malformation of lung, counseling, fetal hydrops, prenatal diagnosis

How to cite this article:
Gobbi D, Filippi E, Bracalente G, Baciorri F, Midrio P. Resolution of Fetal hydrops-not a favorable outcome in congenital pulmonary malformation type 1: A case report with review of literature. Indian Pediatr Case Rep 2023;3:154-7

How to cite this URL:
Gobbi D, Filippi E, Bracalente G, Baciorri F, Midrio P. Resolution of Fetal hydrops-not a favorable outcome in congenital pulmonary malformation type 1: A case report with review of literature. Indian Pediatr Case Rep [serial online] 2023 [cited 2023 Sep 26];3:154-7. Available from:

Congenital pulmonary airway malformations (CPAMs), previously known as congenital cystic adenomatoid malformation (CCAM), are a well-known spectrum of anatomical anomalies of the lungs and respiratory tree. Infants with this diagnosis can present in a wide range of severity from being asymptomatic until later in life, to having respiratory distress right in the neonatal period. The prognosis is poor in macrocystic CPAM, and cyst drainage may be considered if there is concurrent mediastinal shift and/or hydrops; the CPAM volume ratio (CVR) is >1.6, and there are no other abnormalities.[1] The overall survival ranges from 68% to 77% in fetuses with hydrops.

We report a case of macrocystic CPAM with hydrops, diagnosed in the antenatal period, and its neonatal outcome. In addition to highlighting the need for multidisciplinary management from the onset, we report a review of literature, discussing alternatives that may be considered in families who do not accept termination of pregnancy (TOP) as an option.

  Clinical Description Top

A 29-year-old primigravida woman was referred to our prenatal services at 24 weeks of gestation with the suspicion of CPAM, based on second-trimester ultrasound findings. The image in question showed the left fetal lung to be markedly enlarged and entirely substituted by multiple large cysts. The huge multicystic lesion [Figure 1] occupied the entire left hemithorax, but no dominant cyst was recognizable in the right lung. The fetus exhibited radiological features indicating hydrops, scalp edema, ascites, hydrocele, and polyhydramnios [Figure 2]; mediastinal shift and bilateral diaphragmatic inversion; and an amniotic fluid index of 10 (normal range: 8–18). No other malformations or signs suggestive of fetal anemia were found. A radiological diagnosis of CPAM type 1 was made with a CVR of 4.7; CVR is an ultrasonographic indicator that represents the volume of the lesion in relation to the lung mass and may be predictive of the development of hydrops if >1.6.[2] The mother was otherwise healthy and was receiving her supplements.
Figure 1: Twenty-four weeks. Sonographic appearance of fetal huge congenital pulmonary airway malformation type 1; multiple cysts are present (white arrow), no dominant cyst is visible

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Figure 2: Fetal ascites (white arrow) and polyhydramnios (white star) at diagnosis

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  Management and Outcome Top

The couple was counseled about the nature and range of severity of the condition and associated prenatal and neonatal mortality rate. Cyst drainage could not be offered as cysts were small and multiple. In view of associated complications, the prognosis was considered very poor and TOP was discussed as an option, but the parents refused. The pregnancy was monitored weekly. The hydrops and ascites worsened over the following 4 weeks (by 28 weeks' gestation). Doppler studies of the umbilical and middle cerebral arteries and ductus venosus were normal.

At 31+5 weeks, an unusual observation was made – the hydrops and polyhydramnios started to regress spontaneously and displayed complete resolution within the subsequent 2 weeks. There was, however, neither change in the size of the cysts nor the mediastinal shift, though the CVR decreased to 2.5 (still >1.6) by 34 weeks of gestation. This was indicative of a “relative” reduction of the mass volume due to fetal growth, rather than decrease in the size of the lesion. The maternal condition remained stable with no clinical evidence of preeclampsia or mirror syndrome (a condition in which the pregnant woman develops generalized edema, with pulmonary involvement, and thus “mirrors” hydropic fetus and placenta).

A baby girl weighing 2.6 kg was delivered vaginally in the same institute at 38+3 weeks after spontaneous labor. A highly skilled team comprising neonatologists and a pediatric surgeon were in attendance. The Apgar score was 1 and 3 at 1 and 5 min, respectively. The newborn had no signs of peripheral edema, but there was no spontaneous respiratory activity, thus necessitating intubation and manual ventilation. The baby remained cyanosed when, despite initiation of synchronized intermittent mandatory ventilation and the highest ventilatory settings, we were unable to maintain oxygenation saturation. The baby went into irreversible shock secondary to persistent hypoxemia and died within a few hours.

The autopsy revealed that the total wet lung weight (LW) was 11.2 g (normal at term being 40 g) and LW-to-body weight ratio was 0.004 (normal in term newborns being 1.79). The malformed left upper lobe weighed 80 g. The remaining lobes were hypoplastic, with the left lower lobe weighing 2.2 g, and the right lung 9 g. The overexpanded upper left pulmonary lobe had led to severe hypoplasia of the remaining left and right parenchyma. The heart had normal anatomical connection with the large arteries, and no evidence of any septal defect was evident. No other systemic malformation was present.

Histopathology of the lung left revealed multiple cysts that were lined with cubic and columnar epithelium and lacked hyaline cartilage, and hamartomatous alterations compatible with type 1 CPAM [Figure 3]. No other major or minor congenital anomalies were identified in the newborn.
Figure 3: The histological examination revealed a multicystic mass with cysts varying in size from 1 to 3 cm, surrounded by smaller cysts. There is intracystic communication with no apparent connection to the tracheobronchial tree. H and E, ×2, ×5, ×10

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  Discussion with Review of Literature Top

The above case depicts the dismal prognosis of severe CPAM with hydrops, which, despite being diagnosed antenatally, followed up, and monitored regularly, with resolution of hydrops well before term, and delivery being assisted by a multidisciplinary team, still could not be compatible with postnatal life, owing to the underlying pulmonary hypoplasia.

CPAMs are a heterogeneous group of cystic and noncystic lung lesions that result from early airway maldevelopment, as early as the first 6 weeks of gestation. The etiopathogenesis for failure of maturation of the bronchiolar structures with overgrowth of the terminal bronchioles at the expense of the alveoli is still unknown. The lesion can affect any lobe of the lung and is usually unilateral. Approximately 95% of patients with CPAM who are diagnosed antenatally survive.[3],[4] The condition can be categorized into different types, based on origin and morphology [Table 1]. The classification (whether macro- or microcystic) has prognostic implications, fetuses with macrocystic lesions having worse outcomes.
Table 1: Classification of congenital pulmonary airway malformation

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Regardless of the underlying mechanism of compression, the earlier it develops antenatally, the more severe it is and the poorer the prognosis. The role of various antenatal predictive indicators has been explored in terms of complications and neonatal outcomes. The CVR, which was assessed in this case, is one of the most popular indices with values higher than 1.6 associated with increased (up to 80%) risk of hydrops. It also correlates with requirement for TOP, the need for prenatal intervention, postnatal respiratory assistance, and perinatal death. Mass-to-thorax ratio is another index that can be easily measured and could become a valid predictive tool.[4],[5] Maximal lung-to-volume ratio >0.34 cm3 estimated by ultrasound and/or >24 cm3 by magnetic resonance imaging in the third trimester correlates strongly with postnatal respiratory distress.[6] Another parameter that is used but is considered less informative is the observed-to-expected lung-to-head ratio. However, there is still considerable heterogeneity in the predictability and clinical application of these parameters, and some lesions continue to have uncertain or unexpected course of disease. In our case, the fetus presented with several parameters which are predictors of poor outcome, including huge macrocystic mass, CVR >4 that continued to increase with gestation, nonimmune hydrops, and polyhydramnios.

Cystic aspiration/drainage may be considered in macrocystic CPAM with a “dominant” cyst (i.e., one which constitutes greater than a third of the size of the CPAM), since these increase rapidly due to the fluid accumulation and result in mediastinal and lung compression. In this patient, we could not offer this intervention due to multiple large cysts (>2 cm). Some authors have reported resolution of hydrops after antenatal betamethasone therapy, but the response is not predictable.[1],[7],[8],[9] In a prospective study by Curran et al. from the USA, 16 patients with predominantly microcystic CCAMs, all having a CVR >1.6, 9 of whom had nonimmune hydrops fetalis, were treated with prenatal steroids. A total of 13 fetuses, who came for follow-up, survived till delivery, and 11 of them were discharged home. After a course of steroids, CVR decreased in 8 (61.5%) of the 13 patients, and hydrops resolved in 7 (77.8%) of the 9 patients with hydrops, the remaining two patients with nonresolution of hydrops could not survive.[10]

When CPAM is complicated by hydrops, fetal intervention is not possible, resulting in almost 100% mortality.[1],[8],[9],[10],[11] Thus, TOP is often discussed as an option with families, as wa s done in this case.

In this case, hydrops and ascites disappeared spontaneously between 31 and 33 weeks of gestation, without any intervention. A possible explanation could be due to the relatively good fetal growth which resulted in lower “mass effect” (though the CPAM did not decrease in size) and better fluid homeostasis resulting in the resolution of the hydrops. This was supported by the observation that the right lung started to become visible near term. Three sporadic cases of spontaneous regression of severe and prolonged hydrops, similar to the present case, have been reported earlier [Table 2].[12],[13],[14],[15]
Table 2: Review of literature of published case reports (after the year 2000) of antenatal pulmonary malformation associated with hydrops and their outcomes

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The prognosis of isolated fetal CPAM depends on the size of the mass and the presence of hydrops. There is wide heterogeneity in the incidence of respiratory distress at birth among neonates with CPAM.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Stoiber B, Moehrlen U, Kurmanavicius J, et al. Congenital lung lesion: Prenatal course, therapy and predictors of perinatal outcome. Ultraschall Med 2017;38:158-65.  Back to cited text no. 1
Zhu P, Cheng K, He M, et al. Diagnostic value of congenital pulmonary airway malformation volume ratio for fetal hydrops due to congenital lung malformations: A systematic review and meta-analysis. Orphanet J Rare Dis 2022;17:213.  Back to cited text no. 2
Feghali M, Jean KM, Emery SP. Ultrasound assessment of congenital fetal lung masses and neonatal respiratory outcomes. Prenat Diagn 2015;35:1208-12.  Back to cited text no. 3
Zobel M, Gologorsky R, Lee H, et al. Congenital lung lesions. Semin Pediatr Surg 2019;28:150821.  Back to cited text no. 4
Hellmund A, Berg C, Geipel A, et al. Prenatal diagnosis and evaluation of sonographic predictors for intervention and adverse outcome in congenital pulmonary airway malformation. PLoS One 2016;11:e0150474.  Back to cited text no. 5
Japanese Study Group of Pediatric Chest Surgery, Kuroda T, Nishijima E, et al. Perinatal features of congenital cystic lung diseases: Results of a nationwide multicentric study in Japan. Pediatr Surg Int 2016;32:827-31.  Back to cited text no. 6
Morris LM, Lim FY, Livingston JC, et al. High-risk fetal congenital pulmonary airway malformations have a variable response to steroids. J Pediatr Surg 2009;44:60-5.  Back to cited text no. 7
Vu L, Tsao K, Lee H, et al. Characteristics of congenital cystic adenomatoid malformations associated with nonimmune hydrops and outcome. J Pediatr Surg 2007;42:1351-6.  Back to cited text no. 8
Leung WC, Ngai C, Lam TP, et al. Unexpected intrauterine death following resolution of hydrops fetalis after betamethasone treatment in a fetus with a large cystic adenomatoid malformation of the lung. Ultrasound Obstet Gynecol 2005;25:610-2.  Back to cited text no. 9
Curran PF, Jelin EB, Rand L, et al. Prenatal steroids for microcystic congenital cystic adenomatoid malformations. J Pediatr Surg 2010;45:145-50.  Back to cited text no. 10
Schrey S, Kelly EN, Langer JC, et al. Fetal thoracoamniotic shunting for large macrocystic congenital cystic adenomatoid malformations of the lung. Ultrasound Obstet Gynecol 2012;39:515-20.  Back to cited text no. 11
Diamond IR, Wales PW, Smith SD, et al. Survival after CCAM associated with ascites: A report of a case and review of the literature. J Pediatr Surg 2003;38:E1-3.  Back to cited text no. 12
Schott S, Mackensen-Haen S, Wallwiener M, et al. Cystic adenomatoid malformation of the lung causing hydrops fetalis: Case report and review of the literature. Arch Gynecol Obstet 2009;280:293-6.  Back to cited text no. 13
Tsao K, Hawgood S, Vu L, et al. Resolution of hydrops fetalis in congenital cystic adenomatoid malformation after prenatal steroid therapy. J Pediatr Surg 2003;38:508-10.  Back to cited text no. 14
Yamashita A, Hidaka N, Yamamoto R, et al. In utero resolution of microcystic congenital cystic adenomatoid malformation after prenatal betamethasone therapy: A report of three cases and a literature review. J Clin Ultrasound 2015;43:451-7.  Back to cited text no. 15


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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