Congenital pulmonary airway malformation type 2 associated with intralobar pulmonary sequestration in an adult patient: a case report

Abstract

Congenital pulmonary airway malformation (CPAM) and pulmonary sequestration (PS) are among the most common congenital lung malformations and their association is extremely rare. In exceptional cases, patients with CPAM remain asymptomatic until adulthood. We report the case of a 30-year-old man who was hospitalized in our pneumology department for fever, cough and chest pain. Radiological and histological findings confirmed the coexistence of CPAM and PS. The patient underwent surgical resection and recovered well. This is one of the few reported cases in the literature that describe the uncommon association of CPAM and PS with an infrequent diagnosis in adulthood. Clinicians should consider congenital malformations in the differential diagnosis of recurrent respiratory infections, particularly when they affect the same pulmonary lobe.

ARTICLE HIGHLIGHTS

• Association of Congenital pulmonary airway malformation and Pulmonary sequestration is very rare

• The diagnosis in adulthood is unusual

• Consider congenital pulmonary malformations when evaluating patients with cystic intrathoracic masses and recurrent respiratory infections.

• Surgery is the preferred treatment for symptomatic patients.

Plain LANGUAGE SUMMARY

Congenital pulmonary airway malformation (CPAM) is a type of unusual tissue in the lung that is in direct communication with the adjacent parenchyma .Pulmonary sequestration(PS) is a piece of lung tissue that doesn’t connect normally and gets blood in an unusual way. These two lesions are the most common congenital malformations of the lung. It is very rare for a person to have both of these conditions at the same time and which remain without symptoms until adulthood. We describe the case of a 30-year-old man who came to the hospital with fever, cough, and chest pain. Tests showed that he had both CPAM and PS in the same part of his lung. He had surgery to remove the abnormal tissue and made a good recovery. Although this combination is very rare, doctors should think about these kinds of birth-related lung problems when someone has repeated lung infections, especially if the infections keep happening in the same part of the lung.

1. Introduction

Congenital lung malformations (CLMs) are rare. The most frequently described malformations include congenital pulmonary airway malformation (CPAM), pulmonary sequestration (PS), bronchogenic cysts (BC), and congenital lobar overinflation [1]. CPAM accounts for 30–40% of CLMs. It is a hamartomatous lesion arising from abnormal lung development, consisting of cystic and/or adenomatous pulmonary areas that communicate with tracheobronchial tree and receive blood supply from the pulmonary circulation [1,2]. In contrast, PS is characterized by a nonfunctioning mass of pulmonary tissue that receives its arterial blood supply from the systemic circulation and lacks communication with the tracheobronchial tree. It accounts for 0.15% to 6.45% of CLMs [3]. The rare association of these two malformations is called hybrid lesions and they are typically diagnosed during the prenatal or neonatal period. There are very few reported cases where CPAM and PS remain asymptomatic until adulthood [4]. However, complications tend to develop in almost all patients often requiring surgical resection. The most common complication is pneumonia, which may respond poorly to medical treatment. Other complications include the development of malignancies, pneumothorax and hemoptysis [5].To the best of the authors’ knowledge, this is the first locally reported clinical case and very few publications [3,6,7] have addressed the adult onset of CPAM and PS. Therefore, we report here an unusual association of CPAM and PS in a patient aged 30 years.

2. Observation

We present the case of a 30-year-old man, a nonsmoker, who was admitted to our pneumology department with fever, productive cough, and left-sided chest pain. He had no significant medical history. On clinical examination, auscultation revealed decreased vesicular breath sounds at the left pulmonary base. Laboratory tests revealed signs of infection with C-reactive protein(CRP) level of 488 mg/L and hyperleukocytosis of 20200/mm³. A chest X-ray revealed left basal excavated parenchymal opacities with multiple hydroaeric levels (Figure 1). Initially, the patient was treated conventionally for left lower lobar pulmonary suppuration with amoxicillin-clavulanic acid 1 gr three times daily for 7 days. The cytobacteriological examination of sputum was noncontributory and bronchoscopy results were normal.

Figure 1.

Chest X-ray showing heterogeneous consolidation in the left lower lobe, with multiple hydro-aeric levels.

A contrast-enhanced thoracic CT scan was performed, revealing that the left basal pulmonary artery originated from the descending thoracic aorta (Figure 2(A)). There was a deformed, non-ventilated and collapsed left laterobasal and posterobasal segments, with numerous cystic formations of varying sizes. The largest cyst measured 67 mm, had a thin, regular wall enhanced after contrast agent injection, and contained air-fluid levels (Figure 2(B,C)). The Chest CT scan findings strongly suspected an association of congenital pulmonary airway malformation (CPAM) and intralobar pulmonary sequestration (IL-PS). Echocardiography ruled out any additional vascular defects or cardiac malformations. Given these findings, a surgical intervention was planned. After resolution of the infection with antibiotic therapy, the patient underwent a left lower lobectomy via a left posterolateral thoracotomy. The intraoperative examination revealed multiple cystic spaces filled with purulent secretions as well as an artery arising directly from the thoracic aorta supplying the left lower lobe .Histological study of the resected tissue showed cysts lined by ciliated columnar epithelium with interspersed enlarged alveoli. The cysts were filled with pools of mucin with foamy macrophages. The adjacent lung parenchyma showed some dilated alveolar spaces. No cartilage was found (Figure 3). Based on the morphological and histological aspects, the diagnosis of CPAM type 2 associated to pulmonary sequestration was confirmed. A final diagnosis of CPAM type 2 associated with IL-PS was established on the basis of imaging and histological findings. The patient remained asymptomatic and was doing well six months after surgery with a chest X-ray showing sequelae of left lower lobectomy.

Figure 2.

 (A) Chest computed tomography with contrast (mediastinal window) reveals the systemic arterial supply (red arrow) of the lesion from the descending thoracic aorta (blue arrow). (B and C) Chest Computed tomography T scan (lung window) showing multiple cystic lesions with air-fluid levels in the posterior part of the left lower lobe.

Figure 3.

(A) HE*200: multiple cysts (0.5–0.8 cm) with mucostasis (black arrows) covered with columnar epithelium. (B) HE*200: features of mucostasis, including pools of mucin and foamy macrophages (black arrow). (C) HE*400: columnar epithelium covering the cysts.

3. Discussion

This case presents an uncommon association of CPAM and IL-PS with an unusual diagnosis in adulthood. Only a few such cases have been described in the literature and adult presentation is exceptionally rare [6,8].

The incidence of CPAM is estimated at 1 per 10,000–35,000 live births, with higher detection rates during the middle trimester of pregnancy. In contrast, pulmonary sequestration (PS) is even less common, with no well-established population-wide incidence [9].

Both CPAM and PS are developmental abnormalities that occur during the branching and formation of bronchial structures. While CPAM is a hamartomatous lesion composed of tissue from different pulmonary origins and is in direct communication with adjacent lung parenchyma, PS consists of nonfunctional lung tissue separated from the normal lung. Importantly, both conditions carry a risk of malignancy [10] and recurrent infections which should be differentiated from acquired post-infectious cystic changes [1].

The association of these abnormalities is described as hybrid lesions. Although the exact cause of these lesions is not well understood, their coexistence suggests a shared pathogenic origin and similar embryogenesis [11]. Current theories suggest that these malformations may result from abnormal tissue growth, airway obstruction, dysplasia or metaplasia of normal tissues. It is widely thought that the disruption occurs during the pseudoglandular phase of lung development, which occurs between 7 and 17 weeks of gestation [12]. According to Simonet et al. CPAM corresponds to an early arrest in lung development [13]. A second theory attributes its origin to anomalies in the mechanisms regulating lung growth and maturation, which are related to the overexpression of growth factors [14].

Pulmonary sequestration is classified into two types: extralobar pulmonary sequestration (EL-PS) and intralobar pulmonary sequestration (IL-PS). Extralobar sequestration corresponds to dysplastic bronchopulmonary tissue that has its own pleura. However intralobar sequestration is surrounded by normal lung tissue and is the more common form. IL-PS shares similarities with CPAM, with the main difference between them is their histology [15].

There are three common imaging manifestations of intralobar sequestration: consolidation, cystic or multicystic lesions and solid masses or nodules [16]. The most common source of arterial supply for pulmonary sequestration arises from the thoracic aorta [17].

While most cases of IL-PS are diagnosed in childhood, up to 50% are identified after the age of 20. The left lower lobe is the most commonly affected site, as observed in our patient [18]. A contrast-enhanced CT scan is the primary diagnostic tool, as it visualizes the aberrant arterial supply. CT angiography is considered the gold standard for noninvasive diagnosis [17].

CPAM is a group of cystic and/or adenomatous lesions in the lungs and is the most prevalent congenital pulmonary malformation, accounting for 30–40% of congenital lung abnormalities [3,9]. It is classified into five subtypes, based on the resemblance of the lesion to different portions of the airway, from proximal to distal [2,15].

A contrast-enhanced CT scan or CT angiography is crucial for diagnosing CPAM, as it allows visualization of the abnormal lung parenchyma and vascular supply. Bronchography does not provide additional information and is not routinely recommended [17]. It is important to screen for associated malformations, as up to 18% of children with CPAM present with visceral anomalies, according to Stocker’s research [19,20].

Despite CPAM and PS are the two most commonly diagnosed CLMs in utero, histopathological assessment of lung tissue is necessary to confirm the diagnosis of hybrid lesions and to identify the CLMs subtype, particularly in postnatally and in adulthood [1].

4. Management and prognosis

For symptomatic pulmonary sequestration, surgical resection is the standard treatment, particularly for IL-PS in order to prevent the risk of severe hemoptysis [21]. Some authors have proposed nonsurgical management through embolization of the vascular pedicle, but this approach increases the risk of recurrent infections. Postoperative outcomes following surgical treatment remain excellent [22].

The management of asymptomatic CPAM remains controversial. Some authors recommend surgical resection due to the risk of malignant transformation, which is higher in adults than in children [19].

For symptomatic CPAM, surgery is the preferred treatment. Lobectomy, performed via thoracotomy or thoracoscopy, is the most common surgical approach [1].

5. Conclusion

This case highlights the rare and unusual diagnosis of hybrid congenital lung malformation in adulthood. To date, only a few cases of CPAM associated with pulmonary sequestration (PS) have been documented in the English literature.

The clinical presentation can be misleading, as it often involves nonspecific radiological abnormalities and respiratory symptoms that may mimic other differential diagnoses. Awareness of these CLMs is crucial, particularly in patients with recurrent pulmonary infections or atypical radiological findings. The diagnosis of hybrid lesion is based on imaging and histological finding. This case emphasizes the importance of considering congenital pulmonary abnormalities when evaluating patients with cystic intrathoracic masses and recurrent respiratory infections. To minimize the risk of infections and potential malignant transformation, surgical intervention is essential both for achieving an accurate diagnosis and providing definitive treatment.

Funding Statement

This article was not funded.

Author contributions

Asma Knaz: Conception, writing the original drafting, review and editing. Soumaya Boujneh: participate in the writing of the original draft review and editing. Bechir ben Radhia: Operated on the patient, review and editing. Marwa Krifa: examine the resected tissue, provides the pathology picture review and editing. Iteb BenLimem: review and editing .Wafa Benzarti: review and editing. Ahmed Abdelghani: review and editing.

Informed consent disclosure

The authors state that they have obtained verbal and written informed consent from the patient/patients for the inclusion of their medical and treatment history within this case report.

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The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

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Ethical declaration

The authors state that they have obtained verbal and written informed consent from the patient/patients for the inclusion of their medical and treatment history within this case report.