The goal of this clinical trial is to learn which of two minimally invasive procedures is better at safely diagnosing lymphoma in the mediastinum (chest) in adults (aged 18 and older) who are suspected to have either a new or a returning (relapsed) lymphoma. The main questions it aims to answer are:

Which procedure, endobronchial ultrasound-guided transbronchial mediastinal cryobiopsy (EBUS-TBMC) or endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), has a higher success rate in obtaining a definitive diagnosis? Is one procedure safer than the other in terms of complications? Researchers will compare the EBUS-TBMC group to the EBUS-TBNA group to see if the cryobiopsy technique leads to better diagnostic results and has a similar or better safety profile.

Participants will:

Be randomly assigned to undergo one of the two diagnostic procedures (EBUS-TBMC or EBUS-TBNA) during a single bronchoscopy session.

Have their tissue samples analyzed by pathologists. Be followed clinically for at least 6 months to confirm the final diagnosis.

Inclusion Criteria:

• Age ≥ 18 years.
• Presence of mediastinal lymphadenopathy of unknown etiology.
• Clinical suspicion of lymphoma, based on any of the following:

Previous history of lymphoma (suspected relapse). Presence of lymphoma at another site. Clinical and radiographic findings suggestive of new isolated mediastinal lymphoma (e.g., isolated idiopathic bulky mediastinal adenopathy with or without systemic symptoms), as assessed by the study bronchoscopists.

Exclusion Criteria:

• A more probable alternative cause for lymphadenopathy is identified (e.g., lung cancer or other non-lymphoproliferative malignancies).