The occurrence of bronchopleural fistulas is a serious complication after pneumonectomy because of lung cancer and additional bronchial stump coverage within right-sided and left-sided pneumonectomy therefore constitutes the operative standard. This is a case report on the early diagnosis of a lymph node metastasis within the pedicled pericardial fat flap used for bronchial stump coverage. Primary resection of the left lung was carried out 8 months previously because of cancer. Early diagnosis was possible using FDG-PET/CT in the post-operative treatment. The recurrence was successfully treated by en bloc resection and adjuvant radiation.