A case of right middle lobectomy for primary lung cancer in a patient with heterotaxy syndrome.

Background: Anatomical abnormalities in the pulmonary vessels have long aroused great interest among thoracic surgeons, and numerous variations of pulmonary vessels have been reported. Heterotaxy syndrome is an anatomical abnormality in which typically asymmetrical organs, including the lungs, develop symmetrically. We report the case of a 71-year-old man with heterotaxy syndrome undergoing radical lobectomy in the treatment of non-small cell lung cancer.

Case presentation: Computed tomography (CT) revealed an irregular nodule 25 mm in diameter in the right middle lobe. Two months later, at his first visit to our University Hospital, CT revealed a rapidly growing tumor 60 mm in diameter. In addition, three-dimensional (3D) CT revealed the upper and middle lobar bronchi forming a common trunk with the mediastinal type of the right pulmonary artery (PA). The patient underwent video-assisted right middle lobectomy + systematic complete hilar and mediastinal lymph node dissection. The interlobar fissure between the right upper and middle lobes was incomplete, and the common trunk formed by the upper-middle bronchus emerged from an area between the right PA (A¹⁺³) and the right superior pulmonary vein.

Conclusion: The finding of A⁴⁺⁵ branching from the right main PA and descending posterior to the right upper-middle bronchus, which formed a common trunk, resembled a mirror image of the normal left lung. To our knowledge, a common trunk with the mediastinal type of the right PA has never been reported during video-assisted right middle lobectomy. In patients with heterotaxy syndrome, 3D-CT to preoperatively understand their anatomy is essential.