# Isolated Mediastinal and Hilar Lymphadenopathy as a Manifestation of IgG4‐Related Disease Diagnosed by EBUS‐Guided Transbronchial Mediastinal Cryobiopsy

## TL;DR

A case of IgG4-related disease was diagnosed using a new cryobiopsy technique in the mediastinum, offering a minimally invasive alternative.

## Contribution

Demonstrates the successful use of transbronchial mediastinal cryobiopsy for diagnosing IgG4-related disease.

## Key findings

- Transbronchial mediastinal cryobiopsy successfully diagnosed IgG4-related disease in a patient with lymphadenopathy.
- The technique fulfilled 2020 diagnostic criteria after ruling out infections and lymphoproliferative disorders.
- Systemic evaluation confirmed no involvement of other organs in the patient.

## Abstract

Immunoglobulin G4‐related disease (IgG4‐RD) is a fibroinflammatory condition that can involve multiple organs, including mediastinal lesions. Transbronchial mediastinal cryobiopsy has recently emerged as a novel sampling technique that improves diagnostic yield for mediastinal lesions, particularly in rare tumours and benign disorders, compared to endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA). Here we report a case of IgG4‐RD presenting with hilar and mediastinal lymphadenopathy successfully diagnosed by transbronchial mediastinal cryobiopsy using a ø1.7 mm cryoprobe. The diagnosis was established in accordance with the 2020 revised comprehensive diagnostic criteria for IgG4‐RD, after exclusion of infectious and lymphoproliferative disorders. Endoscopic mediastinal cryobiopsy may represent a valuable and minimally invasive strategy for diagnosing mediastinal diseases.

We describe a case of mediastinal and hilar lymphadenopathy diagnosed as IgG4‐RD by transbronchial mediastinal cryobiopsy, fulfilling the 2020 diagnostic criteria, with systemic evaluation confirming no other organ involvement.