Impact of Right Top Pulmonary Vein Location on Subcarinal Lymph Node Dissection in Thoracoscopic Esophagectomy: A Case Report and Literature Review.

Introduction: The right top pulmonary vein (RTPV) is a rare anatomical variant that arises independently of the right superior lobe. It drains behind the right main bronchus or bronchus intermedius and into the left atrium or another pulmonary vein. This anomaly poses challenges during subcarinal lymph node dissection in thoracic surgery, such as esophagectomy, owing to the risk of vascular injury. The RTPV is mainly located behind the right main bronchus and right intermediate bronchus; however, reports of subcarinal dissection focusing on these sites are lacking. Herein, we present a case of esophageal cancer with an RTPV that was treated with thoracoscopic esophagectomy and propose a convenient classification for the anatomical findings and RTPV site.

Case presentation: A 71-year-old man underwent a thoracoscopic esophagectomy for esophageal cancer (T1bN0M0) during a routine medical checkup. A preoperative computed tomography scan revealed an anomaly in which the RTPV drained into the left atrium behind the right main bronchus. Radical subcarinal lymphadenectomy was performed while preserving the RTPV, using 3 dimensions for preoperative simulation and intraoperative navigation. The operation lasted 6 h and 42 min, and the blood loss volume was 30 mL. The patient's postoperative course was uneventful, and he was discharged on postoperative day 21.

Conclusions: In a retrospective review of esophageal cancer surgery cases at our hospital, RTPV was observed in 17/314 cases (5.4%). The most common inflow site was the inferior pulmonary vein (IPV) (9 cases), followed by the left atrium (5 cases), superior pulmonary vein (2 cases), and superior branch of the IPV (1 case). The inflow site was behind the right main bronchus and the right intermediate bronchus in 4 and 13 cases, respectively. Compared to past reviews, the inflow site varied somewhat; however, the vascular location remained the same. By classifying the areas behind the right main and right intermediate bronchi as Zones 1 and 2, respectively, cases in which the RTPV runs through Zone 1, as identified on preoperative computed tomography, should be manipulated with caution due to the risk of injury during lymph node dissection beneath the tracheal bifurcation.