Pediatric Cryptococcosis Presenting as a Mediastinal Mass: A Case Report And Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration Protocol

Summary

This visualized case report presents a clinical protocol for performing endobronchial ultrasound-guided transbronchial needle aspiration via a laryngeal mask airway to support the diagnosis of pulmonary cryptococcosis presenting as an unexpected mediastinal mass in an immunocompetent pediatric patient.

Abstract

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive diagnostic technique. While widely used in adults, its application for diagnosing mediastinal masses in pediatric patients remains underreported. This gap poses challenges when addressing atypical presentations, such as pulmonary cryptococcosis in immunocompetent children, which is frequently misdiagnosed due to nonspecific symptoms. We present the case of a healthy nine-year-old male with an eight-day history of fever and cough. Computed tomography revealed a mediastinal mass in the left hilum and a mass in the left lower lobe. Following unsuccessful empirical antibiotic therapy, further invasive investigation was warranted. This article describes an EBUS-TBNA protocol tailored for pediatric patients. The procedure was performed using total intravenous anesthesia and a laryngeal mask airway. An ultrasound bronchoscope was advanced, and Doppler imaging was used to confirm the target lymph node's relationship with the surrounding vasculature. In this case, a lesion under the second carina was identified. A 22 G aspiration needle was inserted to a depth of 1–2 cm. Maintaining 5–15 mL of negative pressure, 20–30 rapid agitations were performed to obtain samples. The biopsy samples underwent histopathological examination and next-generation sequencing. The tissue demonstrated positive periodic acid-Schiff and Grocott methenamine silver staining, supporting identification of Cryptococcus spp. Following targeted fluconazole therapy, the patient achieved complete clinical and radiographic recovery. This case illustrates the potential usefulness of EBUS-TBNA in a carefully selected pediatric patient when conventional tests fail.

Introduction

Pulmonary cryptococcosis (PC) is a significant fungal infection caused by the encapsulated yeasts Cryptococcus neoformans and Cryptococcus gattii, which are ubiquitous in environmental reservoirs such as soil and avian excreta¹. Historically characterized as an opportunistic infection primarily affecting immunocompromised individuals, particularly those with HIV/AIDS or patients undergoing prolonged immunosuppressive therapy, recent epidemiological shifts have highlighted a concerning rise in incidence among immunocompetent hosts^2,3. In China, over 50% of PC cases now ....

Protocol

This protocol was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Children and Adolescents' Health and Diseases (Approval No. 2026-IRB-0151). Written informed consent was obtained from the patient's parent or legal guardian for both the procedure and the publication of this case report, including any identifiable clinical images.

1. Preprocedural evaluation and preparation

1. Preprocedural chest computed tomography (CT) scans were reviewed to identify ....

Results

Table 1 summarizes the patient's clinical characteristics, procedural parameters, and multidisciplinary management timeline. Baseline laboratory evaluations revealed leukocytosis (white blood cell count: 19.32 × 10⁹/L) with neutrophil predominance and an elevated C-reactive protein level of 52.49 mg/L. Organ function tests, tumor markers, and initial infectious disease screenings, including tuberculosis, HIV, and serum cryptococcal antigen testing, were unremarkable. Initial diagnostic imaging.......

Discussion

The present case described a rare clinical entity: pulmonary cryptococcosis (PC) presenting as an atypical mediastinal mass in an immunocompetent 9-year-old child. The diagnosis was achieved through an endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) protocol, providing a minimally invasive alternative to traditional surgical interventions. While Cryptococcus species are typically recognized as opportunistic pathogens in immunocompromised individuals, localized PC in immunocompetent h.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1% Lidocaine Hydrochloride Injection	Aspen Pharmacare	NMPA Approval No. H20103516
10% Neutral Buffered Formalin	Sigma-Aldrich	HT501128
22 G Aspiration Needle	Olympus Corporation	NA-201SX-4022
4.2-mm Flexible Diagnostic Bronchoscope	Olympus Corporation	BF-P260F
Endobronchial Ultrasound Bronchoscope	FUJIFILM Corporation	EB-530US
Endoscopic Ultrasound Processor	FUJIFILM Corporation	SU-9000
Grocott Methenamine Silver (GMS) Staining Kit	Cida Biotechnology	CD-GMS-100
Laryngeal Mask Airway (Size 3)	Ambu A/S	Ambu Aura-i, 321300000
Metagenomic Next-Generation Sequencing (mNGS) Service	Shanghai KingMed Diagnostics Co., Ltd.	Custom Service; www.kingmed.com.cn
Multi-parameter Patient Monitor	Mindray Bio-Medical Electronics	cPM 10C
Periodic Acid-Schiff (PAS) Staining Kit	Shaanxi ProAndti Biotechnology Co., Ltd.	PA-0054
Propofol Emulsion for Injection	AstraZeneca	NMPA Approval No. H20010368
Remifentanil Hydrochloride for Injection	Yichang Humanwell Pharmaceutical Co., Ltd.	NMPA Approval No. H20030197