We present a rare complication of microwave ablation (MWA) in a male patient in his 80s. His massive pulmonary necrosis and tension pneumothorax required urgent surgery. However, the damage to the lung tissue was too large, deep and fragile. We failed to suture or conduct wedge resection on the lung lesion, so, left upper lobectomy was necessary. Therefore, we suggest that it is probably possible to reduce the frequency and time threshold when performing MWA for the elderly with comorbidities.