Introduction: Pulmonary arterial hypertension (PAH) is rare in the presence of malignancy and tumour embolisation is one of several possible pathological mechanisms.
Case reports: We report our experience of 5 clinical cases and undertake a literature revue of the pathophysiological mechanisms and of the possible diagnostic and therapeutic approaches.
Conclusions: Neoplastic PAH due to tumour micro-emboli is rare and the diagnosis difficult to establish. Cytological examination of pulmonary arterial blood could allow early institution of appropriate chemotherapy and lead to an improvement in the grave prognosis of this condition.