A 68-year-old male was discovered to have a pulmonary nodule in a CT scan for 4 years with no apparent symptoms. The latest CT scan (10/2021) indicated a blade-like hyperdense shadow (2.4 cm x 2.0 cm) in the lower-left lung (Figure 1), which had a higher density than before (06/2019). The positron emission tomography/CT (PET/CT) showed that the standard uptake value (SUV) max of the nodule was 8.1 and had high suggestive of malignancy. Both CT and PET/CT reported that the nodule was located in the left dorsal segment (S6) (Figure 1). Considering the possibility of high suggestive malignancy, it was planned for this patient to receive a video-assisted thoracic surgery (VATS) lobectomy of the left lower lobe.
During intraoperative exploration, the patient was found to have a complete fissure splitting the upper lobe into two lobes (Figure 2). The accessory fissure completely splits the apicoposterior segment (S1 + 2) from the upper lobe. Therefore, there were three lobes in the left lung, including the S1 + 2 as an accessory lobe, the rest of the upper lobe, and the lower lobe. In addition, the target nodule was actually in the S1 + 2, not the S6 considered before surgery.
The surgery was changed to a segmentectomy of the S1 + 2. After the surgery, the patient recovered well and was discharged from the hospital after three days. The pathology of the lung nodule was granulomatous inflammation with caseous necrosis, with the positive antacid stain. The patient was eventually diagnosed with tuberculosis.
This misdiagnosis of location could be avoided, as the additional fissure, the real bronchus, and vessels of S1 + 2 and S6 were not tricky to identify in preoperative CT (Figure 3). Figure 4 shows a three-dimensional (3D) reconstruction of the lungs. The nodule was located in the S + 2, adjacent to the S6. A1 + 2a and A1 + 2b come from the posterior ascending artery, while A1 + 2c comes from the first trunk of the pulmonary artery.