The role of subsegmentectomies in thoracic surgery is still questionable, and the literature is rare (1). The complete resection of subsegment vascular hilum, coupled with the secure preservation of adjacent hilar segment structures, particularly in anatomically variant cases, could contribute to a significant improvement in recurrence results and postoperative recovery due to greater anatomic precision (2). However, such precision mandates extensive preoperative mapping, a task facilitated by advancements in 3D surgical planning technology.The 3D planning with open-source software and handling of the reconstructed image during the procedure enable the recognition of anatomical landmarks and the intraoperative clarification of doubts (3). A 3D Slicer lung segmentation workflow was introduced during resident training to provide reproducibility of the 3D study at a low cost. The images can be actively rotated and visualized from the same angle of the scope with an interactive interface, providing information on the relationship between structures with other series showing good accuracy between 3D models and intraoperative bronchial, and vessels distribution, improving the safety and reliability of those procedures (4, 5).This case illustrates the role of low-cost advanced imaging and preoperative planning in executing complex thoracic surgeries. It also opens the discussion regarding subsegmental resections and their role in the thoracic surgery armamentarium.A sixty-seven-year-old man, treated previously for chondrosarcoma of the right femur with surgery and radiotherapy, presented with lung metastasis in the right upper lobe on an eighteen-month follow-up computed tomography (CT) scan. After an initial VATS wedge resection with clear margins, a nine-month follow-up CT suggested neoplastic recurrence, which was confirmed by transthoracic needle biopsy.The patient, a non-smoker with suitable respiratory function (FEV1 2.56L – 80 percent, FVC 3.37 – 82 percent, DLCO 67 percent), underwent further preoperative evaluation. Enhanced planning using 3D Slicer software provided detailed anatomical visualization and surgical mapping, revealing the lesion in the apicalis proprius subsegment (S1a) of the apical upper lobe segment (S1), closely associated with the subsegmental artery (A1a). This finding, and the recurrent characteristic of the lesion, led to the decision to undergo an anatomical resection. The elected procedure was a subsegmentectomy of S1a, aiming ...