When the heart and tumours intertwine: pulmonary hypertension associated with a neuroendocrine tumour-a case report.

Background: Pulmonary hypertension caused by extrinsic pulmonary vascular compression secondary to mediastinal neuroendocrine tumours is a very rare condition, posing a diagnostic challenge. There is no clear consensus regarding the best treatment strategy due to the lack of clinical data, leading to poor prognoses for these patients. Case summary: We present the case of a 38-year-old man hospitalized with signs of pulmonary hypertension and acute heart failure. He had experienced progressive dyspnoea over the 12 months prior to admission. Studies performed at our institution revealed dilation of the right heart chambers with right ventricular systolic dysfunction and pulmonary hypertension. Cardiac tomography showed extrinsic vascular compression, leading to emergency endovascular treatment for superior vena cava syndrome, followed by stent implantation in the pulmonary arteries and innominate vein. Further studies identified a mediastinal neuroendocrine tumour, for which chemotherapy was initiated, without clinical response. During outpatient follow-up, cardiac function worsened, and the patient died 48 months after symptoms onset due to a lung infection. Discussion: Pulmonary hypertension secondary to extrinsic vascular compression by mediastinal tumour is a rare condition that presents a diagnostic challenge. This case highlights the importance of considering oncological aetiology in patients with progressive dyspnoea and pulmonary vascular extrinsic compression. Despite early treatment, the prognosis for these patients remains poor.