Partial Anomalous Pulmonary Venous Return in Lung Cancer Surgery: Diagnostic Challenges and Surgical Considerations in Two Cases.

PAPVR is a rare congenital anomaly in which pulmonary veins drain into the systemic venous system instead of the left atrium, and when only a single anomalous pulmonary vein is involved, the shunt volume is typically small, allowing asymptomatic progression into advanced age.

• PAPVR occurs in the absence of associated cardiac defects such as atrial septal defect
• Single-vein involvement results in a typically small shunt volume
• Such cases are often incidentally diagnosed or remain undetected due to asymptomatic progression

In Patient 1, PAPVR was successfully identified preoperatively using three-dimensional computed tomography in the lobe with cancer, enabling appropriate surgical planning for lobectomy.

• PAPVR was located in the same lobe as the primary or metastatic lung cancer
• Three-dimensional CT was the imaging modality that allowed preoperative detection
• Preoperative identification enabled appropriate surgical planning

In Patient 2, PAPVR was not recognized preoperatively on conventional two-dimensional computed tomography but was only identified postoperatively, and was located in a different lobe to the one with cancer.

• Conventional two-dimensional CT failed to detect PAPVR preoperatively in this case
• PAPVR was discovered only after surgery
• The anomalous vein was in a different lobe from the cancerous lobe
• Segmentectomy was performed in this patient to preserve lung function

Three-dimensional CT demonstrated superior diagnostic capability over conventional two-dimensional CT for preoperative identification of PAPVR.

• 2D CT failed to identify PAPVR preoperatively in Patient 2
• 3D CT successfully identified PAPVR preoperatively in Patient 1
• Accurate identification before surgery is described as essential in patients undergoing pulmonary resection

Segmentectomy may be a viable surgical option in select cases of lung cancer complicated by PAPVR because it potentially minimizes the reduction in pulmonary blood flow while preserving lung function.

• Segmentectomy was performed in Patient 2 to preserve lung function
• The approach potentially minimizes reduction in pulmonary blood flow compared to more extensive resections
• This is described as applicable in 'select cases' complicated by PAPVR