Pulmonary Veno-Occlusive Disease: A Clue to Underlying Lymphoma.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of post-capillary pulmonary hypertension. Unlike the more common pulmonary arterial hypertension (PAH), PVOD specifically involves the small pulmonary veins. While often idiopathic or genetic, PVOD can occasionally be the presenting symptom of an occult malignancy, such as lymphoma, through direct venous infiltration or extrinsic compression. We report the case of a 31-year-old patient who presented with progressive dyspnea, non-productive cough, and signs of right-sided heart failure. Initial thoracic computed tomography (CT) imaging showed characteristic signs of PVOD: diffuse ground-glass opacities, thickened interlobular septa, and mediastinal lymphadenopathy. Although right heart catheterization was indicated to confirm pre-capillary pulmonary hypertension, it could not be carried out because of the patient's clinical deterioration. A subsequent biopsy of the enlarged axillary lymph nodes confirmed the diagnosis of Hodgkin's lymphoma, suggesting that the pulmonary vascular obstruction was a secondary phenomenon. PVOD is a life-threatening condition that requires high clinical suspicion. In patients presenting with radiological features of PVOD and especially lymphadenopathy, a thorough workup for lymphoma is mandatory. Distinguishing between primary PVOD and malignancy-associated PVOD is crucial, as the use of standard pulmonary vasodilators can trigger fatal pulmonary edema in these patients.