A benign, multifocal, nodular and well-circumscribed neoplasm usually seen as a congenital neoplasm or in the first year of life. It is characterized by a biphasic growth pattern and is composed of small, undifferentiated mesenchymal cells associated with branching thin-walled vessels and more mature neoplastic spindle cells with abundant eosinophilic cytoplasm in a collagenous stroma. The disease is Monarch Disease Ontology term MONDO_0016824 (infantile myofibromatosis). Also known as: infantile hemangiopericytoma, multicentric myofibromatosis, myofibromatosis.