Background: Systemic hyalinoses are genetic generalized fibromatoses characterized by an accumulation of hyalin in the dermis. Two distinctive syndromes are recognized in the literature: infantile systemic hyalinosis (ISH) and juvenile hyaline fibromatosis (JHF). ISH and JHF are sometimes difficult to separate since they show significant overlap. Observations: We report on 3 children from two unrelated families suffering from JHF. The first child is severely handicapped by joint contracture, massive hyperplasia of the gingivae, diffuse skin papules and subcutaneous nodules occupying the scalp, face, perianal area, palms, soles and chest. At the same age, the second child only shows pearly skin papules on the face, groin and perianal area and gingival hyperplasia without joint stiffness or any other subjective complaint. The third patient, a brother of the second child, developed mild skin abnormalities by the end of the first year. The occurrence in siblings and consanguinity in the second family suggests autosomal recessive inheritance. Histological skin examination in the 3 cases showed hyaline deposition in the dermis and abnormal ultrastructure of fibroblasts. Biochemical findings showed mucopolysaccharide abnormalities in both families. Conclusion: Our patients do not only illustrate the different expressions of JHF but also show some overlap with ISH, suggesting a common cause for both disorders. Genetic studies will finally answer this question.