Monarch Disease Ontology entry MONDO_0003743 (heart malignant hemangiopericytoma) is a malignant hemangiopericytoma arising in the heart. Also known as: heart hemangiopericytoma, heart spindle cell tumor, heart spindle cell tumour, malignant Cardiac hemangiopericytoma, malignant heart hemangiopericytoma, malignant hemangiopericytoma of heart, malignant hemangiopericytoma of the heart.