Even since Stout's1excellent discussion and clarification of this group of proliferative diseases of fibrocytes occurring in infants and children, these lesions continue to present a problem particularly for the pathologist who must decide whether the tissue removed is non-neoplastic or neoplastic, benign or malignant. It is the purpose of this paper to present a case of fatal disseminated fibromatosis occurring in early infancy and to discuss several interesting aspects of this case. Report of a Case History.—A white male infant was admitted to Denver Children's Hospital at the age of 6 weeks with a history of diarrhea of 10 days' duration. During this period the child averaged 15 stools daily, these being described as "brown and watery." There was one episode of bright red blood in the stools at the onset and also a similar episode just prior to hospitalization. Examination—Physical examination revealed a 7 lb.