Endoscopic Ultrasound With Bronchoscope‐Guided Fine‐Needle Aspiration (EUS‐B‐FNA) in a six‐Month‐Old Infant: A Case Based Review of Literature

ABSTRACT

Endobronchial ultrasound–guided transbronchial needle aspiration (EBUS‐TBNA) is an established, minimally invasive modality for evaluating mediastinal pathologies in adults. However, its application in infants remains extremely limited because of airway size constraints and procedural safety concerns. We report the case of a 6‐month‐old infant presenting with recurrent lower respiratory tract infections and a posterior mediastinal lesion causing bronchial compression. Contrast‐enhanced computed tomography demonstrated a well‐defined cystic lesion in the right posterior mediastinum, with differential diagnoses including bronchogenic cyst, duplication cyst and necrotic lymphadenopathy. Given diagnostic uncertainty and the risks of primary surgical intervention, EUS‐B‐FNA was performed via transoesophageal approach under general anaesthesia. Cytological analysis revealed cyst macrophages and acellular mucoid debris, confirming a bronchogenic cyst. The patient subsequently underwent definitive surgical excision and remained symptom‐free on follow‐up. This case represents the youngest reported infant to undergo successful mediastinal sampling using EUS‐B‐FNA and highlights the feasibility, safety and diagnostic utility of the transoesophageal bronchoscopic ultrasound approach in very young children when performed in experienced centres.

A 6‐month‐old infant with recurrent respiratory infections was diagnosed to have a posterior mediastinal cyst causing bronchial compression, and diagnostic uncertainty prompted minimally invasive evaluation. Transoesophageal EUS‐B‐FNA safely confirmed bronchogenic cyst, followed by successful surgical excision with complete recovery. This case demonstrates the feasibility and diagnostic value of EUS‐B‐FNA for mediastinal lesions in very young children when performed in experienced centres.

1. Introduction

Endobronchial ultrasound–guided transbronchial needle aspiration (EBUS‐TBNA) is an established, minimally invasive modality for evaluating mediastinal pathologies in adults, offering high diagnostic yield and a favourable safety profile [1]. Its application in the paediatric population, particularly in infants, remains limited due to anatomical constraints of the airway. Conventional convex‐probe EBUS bronchoscopes, with outer diameters ranging from 6.6 to 7.4 mm, are designed for adult airways and pose a significant risk of airway obstruction or trauma in children with narrow tracheal diameters [2]. As a result, paediatric EBUS has largely been restricted to older children, and alternative diagnostic approaches for sampling mediastinum are required in younger age groups.

Endoscopic ultrasound with bronchoscope‐guided fine‐needle aspiration (EUS‐B‐FNA) provides a transoesophageal route to access mediastinal structures while avoiding airway instrumentation. Emerging evidence suggests that EUS‐B‐FNA is feasible and safe in children when performed by experienced operators, with diagnostic yields comparable to surgical approaches [3, 4]. Against this backdrop, we report the case of a 6‐month‐old infant with a posterior mediastinal lesion‐ the youngest age in which EUS‐B‐FNA has been used in world literature till date.

2. Case Report

A 6‐month‐old female infant presented with recurrent cough and febrile episodes since the age of 3 months. She was admitted twice for severe pneumonia requiring intravenous antibiotics and oxygen supplementation. She was born full term with an unremarkable perinatal history, had appropriate growth and development history, and was up to date with immunisations. The current admission was for right lower lobe pneumonia. On examination, vital parameters were stable, and respiratory examination revealed bilateral crepitations, more on the right side. Blood reports revealed elevated total leucocyte count (11,650 cells/mm³). Echocardiography excluded congenital heart disease.

Contrast‐enhanced computed tomography of the thorax was performed which demonstrated a well‐defined 2.0 × 1.8 cm iso‐ to hypodense lesion in the right posterior mediastinum, abutting the right main bronchus and oesophagus (Figure 1A). The lesion caused extrinsic compression of the right main and right intermediate bronchus (Figure 1B,C), likely leading to post‐obstructive pneumonia. The possible differential diagnoses included bronchogenic cyst, oesophageal duplication cyst, neurenteric cyst and necrotic mediastinal lymphadenopathy [5, 6]. Given the infant's age, recurrent respiratory symptoms, and diagnostic uncertainty, a multidisciplinary team discussion (MDD) involving a paediatrician, pulmonologist, radiologist and a thoracic surgeon was conducted, and the team decided on diagnostic sampling of the lesion first using a minimally invasive approach, EUS‐B‐FNA.

FIGURE 1.

(A) Contrast‐enhanced CT chest demonstrating a well‐defined iso‐ to hypodense lesion measuring (white arrow) 2.0 × 1.8 cm in the right prevertebral posterior mediastinum. (B, C) parenchymal window of the CT chest showing narrowed right intermediate bronchus (black arrow), and right lower lobe air trapping. (D) Endoscopic ultrasound image using an EBUS scope (EUS‐B) showing a well‐defined cystic lesion measuring 15.7 × 10.8 mm.

The procedure was performed under general anaesthesia after administration of prophylactic intravenous ceftriaxone. A size 3.5 endotracheal tube was secured, and an Olympus BF‐UC190F convex‐probe EBUS bronchoscope (outer diameter 6.6 mm) was introduced transoesophageally alongside the tube. Endoscopic ultrasound revealed a well‐circumscribed hypo‐ to anechoic cystic lesion in the posterior mediastinum measuring 15.7 × 10.8 mm (Figure 1D). Fine‐needle aspiration was performed using a 22‐gauge needle under suction, yielding approximately 3 mL of clear mucoid fluid (Figure 2A,B). Continuous electrocardiographic monitoring, pulse oximetry, blood pressure monitoring, and end‐tidal carbon dioxide monitoring were employed throughout the procedure under the supervision of a paediatric anaesthesia team. The procedure was completed successfully without oxygen desaturation, haemodynamic instability, bleeding, airway compromise or any other immediate procedure‐related complications. The infant recovered uneventfully following anaesthesia.

FIGURE 2.

(A) Endoscopic ultrasound using the EBUS scope (EUS‐B) demonstrating fine‐needle aspiration (FNA) with the needle in situ within the lesion. (B) Mucoid cyst contents aspirated into a VacLock syringe attached to the aspiration needle. (C) Cytological examination showing cyst macrophages and acellular debris in a mucoid background, consistent with a bronchogenic cyst.

Cytological examination showed cyst macrophages and acellular debris in a mucoid background without significant inflammation (Figure 2C). Bacterial cultures and AFB smear, GeneXpert for Mycobacterium tuberculosis as well as MTB culture were negative. Based on clinical, radiological and cytological findings, a diagnosis of posterior mediastinal bronchogenic cyst causing extrinsic airway compression and recurrent lower respiratory tract infections was established. After stabilizing the child with antibiotics, she underwent a surgical excision of the mediastinal bronchogenic cyst. The child is currently symptom‐free at 6‐month follow‐up.

3. Discussion

The current case is the youngest case in the world literature where mediastinal sampling was performed using an EBUS scope passed through the oesophagus.

Bronchogenic cysts are congenital foregut anomalies arising from abnormal budding of the tracheobronchial tree during early embryogenesis and represent one of the most common mediastinal cysts in children [5]. Although many remain asymptomatic, infants are more likely to present with respiratory distress, cough or recurrent infections due to airway compression. Surgical excision, preferably via video‐assisted thoracoscopic surgery, is considered definitive management; however, surgery in infants carries procedural risks, particularly in the presence of active infection or diagnostic uncertainty. Trans‐bronchial needle aspiration of mediastinal cysts has been shown to be helpful in confirming the diagnosis when there is diagnostic uncertainty [6, 7].

This index case presented to us with several challenges. The location of the lesion in the posterior mediastinum associated with recurrent episodes of fever suggested several differentials requiring diagnostic confirmation. A direct surgical resection of the lesion without diagnostic sampling was discussed in the MDD but was not opted for because of the need to rule out tuberculosis as a cause of the lesion. Surgical excision remains the definitive treatment for bronchogenic cysts; however, diagnostic sampling should be considered as the first approach when imaging findings are not pathognomonic and alternative diagnoses such as tuberculosis are possible. In such situations, cyst aspiration can provide cytological and microbiological confirmation and facilitate appropriate treatment planning while avoiding unnecessary surgery. However, aspiration of mediastinal cysts carries potential risks like infection, bleeding and mediastinal contamination. These complications appear to be uncommon when the procedure is performed under sterile conditions with antibiotic prophylaxis and careful patient selection [6, 7]. The airway size of the infant precluded the use of standard EBUS‐TBNA, necessitating an oesophageal approach.

Sampling mediastinal lesions/nodes in children is challenging, with only a few published articles and case series. Prior paediatric studies and systematic reviews have demonstrated the safety and utility of EBUS‐TBNA and EUS‐B‐FNA, predominantly in older children [3, 4, 8, 9, 10]. In children above the age of 6 years, and when the tracheal diameter is more than 9 mm, a conventional EBUS TBNA can be performed through the airway [3]. In children less than 6 years, and when the trachea is less than 9 mm in diameter, the transoesophageal approach is safer, avoids airway compromise, permits safe sampling of posterior mediastinal lesions and provides cytological confirmation. The advent of the thin convex probe EBUS bronchoscope (TCP‐EBUS) with an outer diameter of 5.9 mm can widen the purview of paediatric EBUS cases being performed.

In European and Indian multicentre series, EBUS‐TBNA and EUS‐B‐FNA have been shown to be technically feasible and safe in older children, with diagnostic yields approaching those of surgical techniques when rapid on‐site evaluation (ROSE) is available [9, 11]. However, there are very few case reports of EUS‐B‐FNA being performed in children less than 3 years of age. A literature search was performed using PubMed, Scopus and Google Scholar databases, and the reference lists of relevant articles were manually reviewed. The search identified only four cases (including the index case) where EUS‐B‐FNA was performed in younger children (less than 3 years) and infants (Table 1) [10, 12, 13]. To the best of our knowledge, the present case represents the youngest child in world literature in whom EBUS guided mediastinal sampling though the oesophagus was performed safely. The index case adds to the growing body of evidence that in young children, when indicated, an EUS‐B‐FNA guided sampling of the mediastinal lesions can be safely performed. This case demonstrates the adaptability of advanced endoscopic ultrasound techniques in the youngest paediatric patients when performed in experienced centres.

TABLE 1.

Clinical and procedural details of infants and children < 3 years of age in whom EUS‐B‐FNA was performed.

Author, Year of publication	Age	Clinical presentation	CT findings	Target lesion and stations	Needle	Diagnosis
Karan Madan et al., 2015 [12]	3 years	Fever and dry cough of 3 month duration	Enlarged paratracheal and subcarinal lymph nodes	Station 7	21 G TBNA	Tuberculous lymphadenitis
Ravindra Mehta et al., 2017 [13]	20 months	Acute onset dyspnea and wheeze	Enlarged paratracheal and subcarinal lymph nodes	Stations 4 L & 7	21G TBNA	Diffuse large B‐cell lymphoma
Manoj Madhusudan et al., 2025 [10]	9 months	Details NA	Mediastinal lymphadenopathy	Stations 4 L	21G TBNA	Tuberculous lymphadenitis
Index case	6 months	Recurrent episodes of pneumonia	Well‐defined lesion (2.0 × 1.8 cm) in posterior mediastinum.	Station 7	22G TBNA	Mediastinal bronchogenic cyst

Abbreviations: NA, not available; TBNA, trans bronchial needle aspiration.

Author Contributions

Venkata Nagarjuna Maturu: performed the procedure, reviewed the manuscript. Srinivas Jakka: managed the patient, reviewed the manuscript. Meghna Rai: drafted the manuscript, reviewed the literature. Rinoosha Rachel: managed the patient, drafted the manuscript.

Funding

The authors have nothing to report.

Consent

The authors declare that consent was obtained for the publication of this manuscript and accompanying images using the form provided by the Journal. Consent is obtained from the parent as the patient is only 6‐months old.

Conflicts of Interest

The authors declare no conflicts of interest.

Maturu V. N., Jakka S., Rai M., and Rachel R., “Endoscopic Ultrasound With Bronchoscope‐Guided Fine‐Needle Aspiration (EUS‐B‐FNA) in a six‐Month‐Old Infant: A Case Based Review of Literature,” Respirology Case Reports 14, no. 10 (2026): e70773, 10.1002/rcr2.70773.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.