A 27-year-old man was diagnosed with inflammatory myofibroblastic tumor, and multiple lymph node and subcutaneous metastases. After several administrations of anti-tumor therapy, he underwent mediastinal lymph node biopsy using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to confirm tumor relapse. Five weeks later, he complained of chest pain, then rapidly developed shock due to acute pericarditis. Although he was treated with antibiotics for anaerobic bacterial infection and cardiac drainage, mediastinal lymph node abscess and pericarditis did not improve. After the surgical procedure, his physical condition dramatically improved and he was treated with another molecularly targeted therapy. Pericarditis associated with EBUS-TBNA is extremely rare. In this case, salvage was achieved by surgical drainage of the lymph node abscess and pericarditis, and long survival was obtained with further administration of anti-tumor treatment.
