Transesophageal Bronchoscopic Ultrasound-guided Cryobiopsy (EUS-B-Cryo) for mediastinal lesions in critical airway obstruction: a case series with a systematic review

Tissue diagnosis of mass lesions in the mediastinum poses a challenge, particularly when the mass is not in direct contact with the chest wall, rendering techniques such as Ultrasonography (USG) or Computed Tomography (CT) guided biopsies ineffective. In cases of Critical Airway Obstruction (CAO), utilizing routine endobronchial ultrasound-guided biopsies can lead to complications, including respiratory failure. As an alternative technique, Transesophageal Bronchoscopic Ultrasound-Guided Fine Needle Aspiration (EUS-FNA) is utilized. However, when smears yield inconclusive results for histopathological diagnosis, mediastinoscopy remains the preferred modality. We present two cases of CAO where Transesophageal Bronchoscopic Ultrasound (EUS-B)-guided cryobiopsy was performed, eliminating the necessity for mediastinoscopy. Histopathological examination of the cryobiopsy samples revealed squamous cell carcinoma and small cell carcinoma. A detailed systematic review only revealed two similar studies in the past. Thus, EUS-B-guided cryobiopsy emerges as a novel technique with the potential to diagnose lesions located in the concealed regions of the mediastinum.