Primary leiomyosarcomas of the pulmonary artery are very rare tumours with 30 cases reported in the English literature. Herein, we report the first case with evidence of a renal metastasis.The tumour was discovered at autopsy in a 61-year-old woman who had presented with shortness of breath and chest pain. It was located in the pulmonary trunk with extension into the adjacent pericardial cavity. Separate nodules were found in the pulmonary valve, the left pulmonary artery and the left kidney.On microscopic examination, the tumour was composed of spindle cells with cigar-shaped nuclei immunoreactive for vimentin, desmin, CD68 and alpha-smooth muscle actin.Primary pulmonary artery leiomyosarcoma is easily confused clinically with pulmonary thromboembolism and most cases are diagnosed post mortem. Most tumours arise in the pulmonary trunk and metastases are only rarely described. The management of patients with this rare tumour depends on early surgical resection and the prognosis is unfavourable.