A poorly circumscribed neoplasm arising from the soft tissues in infants. It is characterized by the presence of bland fibroblastic spindle cells, collagenous stroma formation, primitive mesenchymal round cells, and mature fat cells. These components combined form a distinct organoid pattern. The disease is fibrous hamartoma of infancy (Monarch Disease Ontology entry MONDO_0006211). Also known as: fibrous hamartoma, infantile fibrous hamartoma.