Background. Partial anomalous pulmonary venous return (PAPVR) is an uncommon congenital abnormality, which may present in the adult population. It is often associated with sinus venosus defect (SVD). The diagnosis and therapy for this condition may be challenging. Case Presentation. We describe a case of an elderly woman who presented with NYHA Class IV dyspnea and was suspected to have symptomatic pulmonary hypertension. She was later found to have anomalous right upper pulmonary vein return to the superior vena cava and associated SVD with bidirectional shunting. Therapeutic options were discussed and medical management alone with aggressive diuresis and sildenafil was adopted. Follow-up visits revealed success in the planned medical therapy. Conclusions. PAPVR is a rare congenital condition that may present during late adulthood. The initial predominant left-to-right shunting associated with this anomaly may go undetected for years with the gradual development of pulmonary hypertension and right heart failure due to right heart volume overload. Awareness of the condition is important, as therapy is time-sensitive with early detection potentially leading to surgical therapy as a viable option.