Delayed Diagnosis of Partial Anomalous Pulmonary Venous Return in an Adult With Pulmonary Hypertension

Partial anomalous pulmonary venous return (PAPVR) involving the left upper lobe pulmonary vein is an exceptionally rare congenital anomaly that, if untreated, can lead to pulmonary hypertension (PH). Its nonspecific clinical presentation often results in delayed diagnosis. We report the case of a 58-year-old woman who initially presented with progressive dyspnea and was diagnosed with group III pulmonary hypertension attributed to obstructive lung disease. Two years later, she returned with similar symptoms after discontinuing diuretic therapy. Further evaluation uncovered a previously undetected anomalous left pulmonary vein draining into the left innominate vein. This case highlights the diagnostic challenges of PAPVR, its role in contributing to PH, and the critical need for high clinical suspicion and comprehensive evaluation in patients with unexplained pulmonary hypertension.