An otherwise healthy 52-year-old male (172 cm tall and weighing 74 kg) was scheduled to undergo video-assisted upper lobectomy for left lung cancer. Thoracic paravertebral block (TPVB) was planned using an Esaote ultrasound machine ((MyLab™Alpha, Esaote, Italy) and a low-frequency curvilinear transducer. We chose to perform the TPVB using the out-of-plane parasagittal approach since that is our department’s custom. After placing the patient in the right lateral position, the transducer was placed 2.5 cm lateral to the midline in a sagittal orientation, slightly oblique toward lateral []. Paravertebral space (PVS) between the T4 and T5 transverse processes was detected. This location was between the superior costotransverse ligament and the pleura. A 5-cm 22 G needle (Stimplex®D, B. Braun, Germany) was inserted at the lateral side of the transducer slightly toward medial. During the advancement, the needle tip was not visualised on the ultrasound screen. Only tissue displacement could be seen. Several attempts were performed. At the last attempt, the needle tip was visualised just below the superior costotransverse ligament in the middle of PVS. After a further advancing the needle, anterior displacement of the pleura in the centre of T4–5 PVS was visualised upon injection of the saline. Just before the local anaesthetics were available to be administered, aspiration of red blood was identified. The TPVB in this T4 level was discontinued. Again, we detected the T6 paravertebral level, the technique was the same as that in the T4 level. This time, the entire procedure was uneventful. Appropriate needle tip location was confirmed by displacement of pleura with widening of the intercostal space after injection of the saline. Aspiration through the needle was negative. Fifteen millilitres of 0.4% ropivacaine was injected. During the whole procedure the patient did not have any discomfort, pain or sign of pleural irritation. He was haemodynamically stable. When the chest cavity was entered, the surgeon found that in the left PVS underlying the pleura, there was a bulging, column-shaped haematoma extending from T1 to T12 with concomitant spread into the left T4–5 intercostal space to the post-axillary line. No injury to the lung tissue was identified. The haematoma was left untouched. One gram of tranexamic acid was infused over 15 min. The operation was carried out as according to routine protocol and was uneventful. Following the operation, the patient was started on an intravenous patient-controlled analgaesia (PCA) with sufentanil. On postoperative day 1, the patient complained of severe dynamic pain of 8/10 on a numeric rating score in the nipple area that was not alleviated by the intravenous PCA. Rescue analgaesia was given. A neurologic examination revealed intact sensory function in the T4 dermatome bilaterally and diminished sensation in the left T5-T7 dermatomes. The patient made a full recovery with no neurological sequelae and was discharged one week later.