Lung cancer surgery with partial anomalous pulmonary venous connection presenting an inverted Scimitar sign.

[BACKGROUND] Partial anomalous pulmonary venous connection (PAPVC) is a congenital anomaly in which a part of the pulmonary veins drain into the right heart system. Many cases of PAPVC remain asymptomatic and often do not present clinical problems. However, when performing a lung resection, it becomes important in terms of surgical techniques and complications.

[CASE PRESENTATION] A 70-year-old woman was referred to our hospital for evaluation of an abnomal shadow on chest radiography performed during medical check-up. A contrast-enhanced chest computed tomography (CT) revealed a part-solid nodule in the right upper lobe (RUL). Additionally, PAPVC was observed, in which almost all pulmonary veins, except for a small part of the basal segmental pulmonary vein (PV), drained into the azygos vein. The patient was diagnosed with suspected primary lung cancer (cT1miN0M0, stageⅠA1) with PAPVC. We performed righit upper wedge resection while preserving the PAPVC.

[CONCLUSION] We reported rare PAPVC presenting an inverted Scimitar sign. To the best of our knowledge, this is the first case report of its kind. The tumor was located very close to the main trunk of the anomalous PV. Resection of the main trunk would have resulted in the loss of all pulmonary veins except for the basal segmental PV. Furthermore, the surgical margin would have been unchanged when comparing right upper lobectomy with wedge resection. Therefore, wedge resection of the RUL was selected. The resection margins were negative.

[SUPPLEMENTARY INFORMATION] The online version contains supplementary material available at 10.1186/s44215-026-00245-6.