An unusual case of partial anomalous pulmonary venous drainage

We report a case of partial anomalous pulmonary venous drainage where the left upper and lower pulmonary veins drain into a separate posterior left atrial (LA) chamber before continuing as a vertical ascending vein. The vertical vein then joins the left innominate vein, which eventually drains into a normal right-sided superior vena cava. There was no fenestration or communication between this posterior chamber and the true LA. The true LA contained the fossa ovale and LA appendage. The right upper and lower pulmonary veins drain normally into the true LA. To our knowledge, this is the first case where the left upper and lower pulmonary veins drain into a separate posterior LA chamber before continuing into a vertical vein. The diagnosis was initially made with transesophageal echocardiography and confirmed by magnetic resonance imaging. The patient later underwent successful corrective operation.