Bartonella henselae mediastinal lymphadenitis mimicking malignancy with critical airway compression in a child: a case report.

Cat-scratch disease, caused by Bartonella henselae, is usually a self-limited infection presenting with regional lymphadenopathy in children. Thoracic involvement is uncommon, and mediastinal lymphadenitis with clinically significant airway compression may closely mimic malignancy. We report a previously healthy 6-year-old boy who presented with persistent fever, mild cough, weight loss, and cervical lymphadenopathy. Chest computed tomography revealed necrotic mediastinal lymphadenopathy forming a mass-like lesion with compression of the right middle lobe bronchus and associated atelectasis. Bronchoscopy showed severe bronchomalacia with approximately 90% luminal narrowing, despite only mild respiratory symptoms. Initial antimicrobial therapy failed to improve the clinical or radiologic abnormalities. Because of constitutional symptoms and a necrotic mediastinal mass, lymphoma was strongly suspected; however, bone marrow examination was unrevealing. During biopsy of the mediastinal lesion, purulent material was encountered. Histopathology demonstrated necrotizing granulomatous inflammation, and metagenomic next-generation sequencing identified Bartonella henselae, establishing the diagnosis of cat-scratch disease. Treatment with doxycycline and rifampin led to prompt resolution of fever and marked radiologic improvement, with substantial relief of airway compression. This case highlights that Bartonella henselae infection can present as a necrotic mediastinal mass with severe but reversible airway compression in children. Cat-scratch disease should be considered in the differential diagnosis of pediatric mediastinal masses, particularly when inflammatory features, cat exposure, and discordant respiratory symptoms are present. Integration of imaging, bronchoscopy, pathology, and molecular testing may prevent misdiagnosis as malignancy and underestimation of airway risk.