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Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00684-8
10.1016/j.radcr.2024.07.096
Case Report
Congenital cystic adenomatoid malformation in a toddler: Unusual presentation with pleural effusion
Laanait Radia radia92laanait@gmail.com
⁎
El fakiri Karima
Rada Noureddine
Draiss Ghizlane
Bouskraoui Mohammed
Pediatric A Department, Mohammed VI University Hospital, Marrakesh, Morocco, Faculty of Medicine and Pharmacy, University Cadi Ayyad, Morocco
⁎ Corresponding author. radia92laanait@gmail.com
18 8 2024
11 2024
18 8 2024
19 11 50135017
28 6 2024
16 7 2024
17 7 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Congenital cystic adenomatoid malformation encompasses a series of cystic malformative lesions characterized by aberrant bronchiolar formations of varying size and dispersion. Most cases of this illness are detected in the first few years of life, usually affecting infants. We report a case of CCAM presenting as pleural effusion in a 15-month-old boy who presented with acute respiratory distress. Chest CT revealed a cystic image in the right lower lobe of the lung. The patient had surgical excision, and a pathological examination validated the diagnosis of CCAM type 1 with no malignant material. Following surgery, the patient's general condition improved, and no new respiratory symptoms were observed during an 8-month follow-up period. Increased awareness of this rare condition among pediatricians and radiologists is crucial for facilitating early diagnosis and appropriate treatment.

Keywords

Congenital cystic adenomatoid malformation
Respiratory distress
Pleural effusion
Surgical resection
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pmcIntroduction

Congenital cystic adenomatoid malformation (CCAM), can be defined as an entity caused by defects in the lung's branching morphogenesis at multiple phases during development and in various layers of the tracheobronchial tree. Adenomatoid growth of bronchioles causes cysts to form in place of normal alveolar structure, leading to a deformity including 1 or more cysts with consistent or variable sizes [1,2].

Based on the tracheobronchial tree's origin, the presence of cystic components, radiologic appearance, and size, CCAM is currently divided into 5 categories [3]. CCAM is categorized from type 0 to type IV using Stocker's criteria. Bilateral CCAM is uncommon and is linked to a bad prognosis, whereas Type I CCAM is more prevalent and associated with favorable outcomes [4].

Although it is a hamartomatous disorder, cancer is also linked to CCAM. Examining the family history of malignancies and cystic lesions is crucial since they may contribute to the familial pleuropulmonary blastoma syndrome. If CCAM is not treated promptly and appropriately, it may be fatal [5,6]. Consequently, raising knowledge among adult respiratory doctors may help to prevent incorrect or delayed diagnoses. Pneumothorax, hemoptysis, and recurred chest infections are common manifestations from an extensive list of causes, making CCAM diagnoses especially difficult and easily missed. With the toddler's parent's approval, we report a rare case of congenital cystic adenomatoid malformation.

Case report

A 15-month-old boy was born after a normal pregnancy without any complications. The mother received regular antenatal care, but she did not undergo an antenatal ultrasound examination. The baby had Apgar scores of 9 and 10 at 1 and 5 minutes after birth, respectively.

A 15-month-old child was born following a typical pregnancy with no difficulties. The mother had routine prenatal care, although no antenatal ultrasound exam was received. The baby's Apgar scores were 9 and 10 at 1 and 5 minutes after birth, respectively. There were no congenital abnormalities. The mother reported no history of recurrent respiratory infections, and there was no major family history of pulmonary illnesses.

The child was brought in with the following symptoms: high-grade fever, dry cough, difficulty breathing, poor suckling, and loss of appetite over the past 8 days. He was admitted to the pediatric department due to respiratory distress. During the physical examination, the toddler appeared pale and feverish, with a saturation level of oxygen of 92% on the ambient air and a respiratory rate of 50 breaths per minute. There were visible signs of respiratory distress, including intercostal and subcostal recessions with reduced chest wall mobility on the right side. Additionally, there was a reduction in air entry across the right lower lobe of the lung, with crackling sounds during inhalation. After that, the systemic examination proceeded normally.

Laboratory tests showed microcytic hypochromic anemia, along with neutrophilic leukocytosis and thrombocytosis. Chest X-rays revealed a large pleural effusion in the right lung, with a mediastinal displacement to the left (Fig. 1).Fig. 1 (A) Initial chest X-ray reveals right pleural effusion (arrows). (B) Chest X-ray post chest drainage showing a bulging area (arrows). (C) Chest X-ray after 8 weeks of evolution with aggravation of the bulla image (arrows).

Fig 1

Initially, a chest tube was inserted to allow the right lung to re-expand and to drain 200 mL of purulent fluid from the pleural space. The patient was promptly started on intravenous antibiotic therapy with amoxicillin/clavulanic acid at a dose of 150 mg/kg/day for 6 weeks. This led to significant improvement in respiratory distress and a reduction in fever. However, follow-up chest X-rays after the drainage revealed a decrease in pleural effusion but showed a bulging area in the right lower lobe, raising suspicion of a pulmonary abscess (Fig. 1). The antibiotic therapy was extended to 8 weeks. Afterward, the patient was discharged and will be under weekly supervision.

In order to empty 200 mL of purulent fluid from the pleural space and to allow the right lung to expand again, a chest tube was first placed. The patient was promptly started on intravenous antibiotic therapy with amoxicillin/clavulanic acid at a dose of 150 mg/kg/day for 6 weeks. As a result, there was a noticeable decrease in fever and improvement in respiratory distress. However, follow-up chest X-rays after the drainage revealed decreased pleural effusion. Still, they showed a bulging area in the right lower lobe, raising suspicion of a pulmonary abscess (Fig. 1). The course of antibiotics was increased to 8 weeks. The patient was then released from the hospital and will get weekly monitoring.

Two weeks later, the patient was readmitted for acute respiratory distress, and chest X-rays revealed a deterioration of the earlier bullous picture (Fig. 1). Chest CT revealed a huge bulla (11×8.4×13 cm) originating from the right lower lobe, creating considerable compressive effect of all 3 lobes, mediastinum deviation to the left, and right diaphragm depression coupled with emphysema bullae (Fig. 2).Fig. 2 Axial view of chest CT showing huge bulla originating in the right lower lobe (arrows in [A] and [B]) with compressed lung coupled with emphysema bullae (arrowheads in [A]).

Fig 2

Surgery was scheduled following the parents' informed permission. An expert surgeon carried out the operation. Through a posterolateral thoracotomy, the patient's cystic lesion in the right lower lobe was successfully removed.

A macroscopic examination of the resected specimen revealed many bullae, some of which were burst. The biggest bulla measured up to 75 mm. A microscopic examination showed a huge collapsing multiloculated cyst under the pleura. The cyst had a fibrous material in the wall, intermittent chronic inflammation, and a partial remnant lining made up of a single layer of cilium epithelium in the columnar region and isolated low cuboidal cells. The samples had no mucinous epithelium or cartilage, and there was no sign of cancer. The total results were consistent with CCAM type 1 (Fig. 3).Fig. 3 Histological examination (hematoxylin and eosin (H&E) staining, at 100×) reveals cysts lined by columnar epithelium, with smooth muscle in the cyst walls, with rich capillary vascularization (A). Areas of fibrosis and inflammation were also noted, without any malignancy sign (B).

Fig 3

The patient's recovery after the operation was smooth, and he was discharged on the seventh day after surgery. A follow-up chest X-ray was performed on the 35th day postoperation and revealed normal results. Subsequent clinical examinations and chest X-rays at our clinic every 3 months have shown that the patient has remained asymptomatic for the past 8 months.

Discussion

CCAM is a rare lung hamartomatous abnormality that manifests during development and has no recognized cause. It is not hereditary. The initial description was provided by Ch'in and Tang in 1949 [1]. It is uncertain how CCAM develops. The primary developmental anomaly leading to CCAM has been determined to be either bronchial atresia or maturation block in bronchopulmonary segments before the 17th week of gestation. The dysplastic lung expansion beyond the atretic segment then determines the lesion's form [3,7].

About 80%-85% of CCAM cases are discovered during the early 2 years of life, which is comparable to our situation. Changes in the radiological and histological appearance may result from chronic inflammation brought on by recurrent infections in cases when CCAM is detected later in life [3]. Ultrasonography can also be used to establish the prenatal diagnosis. Even though natural regression has been recorded in up to 76% of cases in the absence of any prenatal treatment, up to 71% of such patients are asymptomatic at delivery [8].

Acute respiratory distress brought on by the cyst expanding and compressing the surrounding structures is the most common mode of presentation. Air is trapped by a ball-valve mechanism, causing distress.

This method of presentation is typical in the neonatal period. It can be asymptomatic and only identified later in life on routine chest images, or it can manifest as recurrent pneumonia following the newborn period [4].

The CCAM may exacerbate as a result of a mycotic, bacterial, or tubercular infection later on. Adult CCAM cases that present as lung abscesses have been reported infrequently [9]. Our case is highly distinctive because of the patient's extremely rare presentation of pleural effusion—of which, as far as we are aware, not many circumstances have been documented in the literature [4,5]—our case is quite unique.

Radiology frequently misdiagnoses CCAM as a pneumothorax, lung cyst, or emphysema bubble [8]. Imaging studies are used to diagnose CCAM; histopathology is the sole confirmatory test. An air-filled cyst-containing mass may be visible on a chest X-ray [10]. Anatomy is shown in greater depth on a CT scan.

On a CT scan, anatomy is displayed in greater detail. Many cystic lesions with fragile walls surrounded by normal lung parenchyma are the typical look. In case of infection covering the lesion, it could make it appear worse [3,7]. Other congenital abnormalities such extralobular sequestration, diaphragmatic hernia, pulmonary hypoplasia, or cardiovascular anomalies may coexist with up to 26% of cases [7].

The treatment course is determined by the severity of the disease and its clinical manifestation. Surgical excision is necessary in the majority of symptomatic cases involving recurrent lung infections or respiratory distress. Asymptomatic cases are closely monitored. In cases where prenatal ultrasonography was used to diagnose the condition, there is evidence of spontaneous regression [5,6].

Few studies have investigated the efficacy of conservative therapy in specific CCAM cases [[11], [12]]. In babies, however, surgical resection paired with curative treatment led to greater survival rates. In the absence of surgical treatment, recurrent infections were the most frequent outcome in asymptomatic neonates during their first few years [13]. The advancement of CCAM surgery has often resulted in better outcomes, including reduced postoperative morbidity and mortality, shorter hospital stays, and, most critically, a lower chance of recurrence [1,7,13]. It may cause varying levels of respiratory failure [13].

In 1977, Stocker et al. [14] identified 3 distinct forms of CCAM; type I, that represents fifty percent of cases, the lesion is composed of a large irregular cystic mass dominated by larger cysts (2cm to 10cm). The cysts are covered with pseudostratified columnar ciliated epithelium that covers a conspicuous fibromuscular layer. Type II constitutes 40% of the cases and is comprised of numerous small cysts (0.5cm-2cm) throughout the lesion without a predominant large cyst component. The lesion is composed of thin-walled bronchiole-like structures. Type III is responsible for 10% of CCAM cases and is composed of several equally distributed tiny cysts measuring less than 0.2cm. The lesion is usually rather extensive, taking up a whole lobe or the majority of 1 lung.

Additionally, reports of CCAM malignant cases have been recorded. The chronic inflammatory response is regarded to be a trigger for malignant transformation. There have been a few reports of bronchoalveolar carcinoma developing in an area of CPAM and progressing to metastatic adenocarcinoma [10,15]. Fortunately, in our patient, histological examination showed no sign of malignancy.

Conclusion

We are sharing this case to highlight the significance of considering CCAM as a possible diagnosis in children who exhibit acute respiratory symptoms. Additionally, we want to raise awareness about pleural effusion as a potential manifestation of CCAM in otherwise asymptomatic patients.

Patient consent

I confirm that written informed consent has been obtained from the involved patient guardian (parent) or if and, they have given approval for this information to be published in this case report, with accompanying images.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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