Inclusion Body Fibromatosis (EFO_1000301, an Experimental Factor Ontology entry) is a rare benign neoplasm arising from the soft tissues of the digits, in young children. It is characterized by the presence of fibroblastic spindle cells, and intracytoplasmic eosinophilic spherical inclusions. Also known as: Reye tumor, Reye's tumor, digital fibrous tumor of Reye, inclusion body fibromatosis, inclusion body fibromatosis (disease), infantile digital fibroma/fibromatosis, infantile digital fibromatosis.